In our results, we show that the inertia against NP elongation increases with size. In other words, NPs with larger diameters require higher electronic stopping powers to be deformed. Since the macroscopic stress induced by heavy ion irradiation in planar constrained films can reach larger values (several hundreds of MPa) [26], we presume that that mechanism (iii) can actively participate in deformation process of the embedded Au NPs. The aforementioned scenario of (iii) has already been introduced by Roorda et al. [12] for verification of the shape change of Au NPs confined within a silica shell and suggested to remain solid during the irradiation. However, this indirect mechanism alone is not enough to correlate the observed deformation of embedded solid NPs [18]. The metallic NP must have an active participation in the elongation process. In other words, the elongation process will only take place when the temperatures of both the metallic NP and the surrounding dielectric matrix exceed their individual melting temperatures [18, 19]. In literature, it has been argued that the melting of metallic NPs with diameters in the range of nearly similar range to our NPs of the current study (6 and 20 nm) cannot be invoked with energy deposition corresponding to the electronic stopping powers in the current work [35]. Particles with relatively larger diameters are not expected to completely melt and virtually are not observed to deform under SHI irradiation, [18, 35, 36]. Awazu et al. [35] report that Au NPs with diameter of about 50 nm are not subject to deform under irradiation with 110 MeV Br ions to a fluence of about 1.0 × 1014 ions/cm2 . For this class of NP size, it is conceivable that a minimum compressive stress is needed to activate the NP deformation. On the other hand, it is necessary to mention that the threshold fluence cannot be directly regarded to the individual track-generated stress [37–39]. This is because the deformation threshold would be only dependable on the electronic stopping. Consequently, macroscopic stress should be invoked to clarify the observations. In this sense, direct correlation between minimum compressive stress and NP size could be established. The larger NP size requires larger (minimum) compressive stress to activate the NP elongation process leading to larger fluence necessary to reach it. The latter hypothesis accounts quiet well for our results for the deformation dependence on initial NP size, ion energy, and irradiation fluence. Furthermore, the variation of the embedded NP areal density has led to identification of two distinct fluence regimes for the NP elongation under swift heavy ion irradiations as follows:

the compaction corresponds slightly to a compromise where all incident neighboring tracks exhibit mutual overlap in such way that the perturbed area covers the overall sample surface.

. (2) Under irradiation with fluences larger than 1014 ions/cm2

material deformation becomes quiet prominent in the further evolution of the system. The latter effect is associated with the tensile stress reduction and the buildup of a com-

 matrix compaction implies the situation whereas the sample surface becomes entirely covered by the mutually overlapping ion tracks, it is conceivable that the resulting deformation threshold depends on the incident ion track diameter. In that sense, the larger the track radius is, the lower the deformation threshold fluence will be. In literature, a number of experimental

amount to 5.4, 6.7 and 9.7 keV/nm). The corresponding track

, respectively.

Considering mechanisms (i) and (ii), we presume that the NP elongation is limited to the accomplishment of the structural transformation of the silica matrix. With the latter in mind, we try to correlate the threshold deformation evolution with the energy of the incident ions. As the end

and theoretical publications have already reported on the ion track cross sections in SiO2

at fluences of 2.0 × 1013, 1.0 × 1013, 0.7 × 1013, and 0.5 × 1013 ions/cm2

tion of the deformation threshold when the incident ion energy is increased.

[30–33]. In these publications, the track size is calculated from the thermal spike model and already found to correspond to the region that melted in the wake of the passing heavy projectile [34]. In our current results, the applied ion energies of 18, 25, and 54 MeV Ag, the corresponding

diameters for these energies in the silica are approximately 3, 4, and ~5 nm, respectively. The calculated corresponding complete overlap of the ion tracks at the surface of the sample is found

Putting on mind that (i) the swift heavy ion irradiation follows random statistics and that (ii) the compaction fluence for a silica matrix containing partially wetted metallic NP can be different from that of pure silica film, our calculations account pretty well for the reported reduc-

In our results, we show that the inertia against NP elongation increases with size. In other words, NPs with larger diameters require higher electronic stopping powers to be deformed. Since the macroscopic stress induced by heavy ion irradiation in planar constrained films can reach larger values (several hundreds of MPa) [26], we presume that that mechanism (iii) can actively participate in deformation process of the embedded Au NPs. The aforementioned scenario of (iii) has already been introduced by Roorda et al. [12] for verification of the shape change of Au NPs confined within a silica shell and suggested to remain solid during the irradiation. However, this indirect mechanism alone is not enough to correlate the observed deformation of embedded solid NPs [18]. The metallic NP must have an active participation in the elongation process. In other words, the elongation process will only take place when

, anisotropic

matrix

**vi.** As mentioned in our experimental part, our grown silica film is not free standing films but constrained by underneath silicon substrate. The stress state of a constrained silica film as an effect of the ion irradiation has been intensively studied in literature [25–27]. Two extremely opposite stress situations depending on the irradiation fluence have been reported as follows: (1) under irradiation at low ion fluences, the initially compressive stress turns into a tensile stress. The latter, which is related to the mechanism of compaction, leads to the structure to a higher equilibrium density state. The maximum value for this equilibrium is reached at the end of the matrix densification for fluences up to few

1013 ions/cm2

30 Ion Beam Applications

of SiO2

pressive stress for the constrained film.

electronic stopping powers in SiO2

The mechanism governing the growth of Au nanowires most likely involves the diffusion through the silica matrix of the gold solute from the dissolved/fragmented nanoparticles toward the growing ones. The task to identify the physical origin of the driving force for preferred Au diffusion from shorter Au nanorods to longer ones, which causes a kind of Ostwald ripening, is difficult.

Some insights can be obtained from **Figure 11(c)** (the inset) and **Figure 14a**, **b** where small fragments are clearly visualized. In fact, those small fragments were not imaged before irradiation; thus, they must be a product of the ion beam irradiation. The energy deposited within the NP subsystem may have allowed the Au atoms and/or species to dissolve in silica. Upon local fluctuation of the solute concentration, the supersaturation of the solid solution then evolves toward the precipitation of the satellite particle phase. Under swift heavy ion irradiation, these small precipitates become unstable [40], and thus they dissolve by subsequent impinging ions (track by track) through the silica matrix. In other words, the diffusion of such nanostructures is driven by the transient melted region formed in the wake of the impinging ions. Dais et al. [41] report on direct observation of the gold diffusion within the ion track. As this process depends on the amount of the available solute sources, i.e., the NP concentration, the lower their relative distance the shorter the diffusion time and the longer the nanowires, as shown in **Figure 13c**, **d** and **Figure 14a**, **b**. On the other hand, when the NP areal density is low, the particle growth is limited by the too long distance between the metal particles. This effect accounts for the relatively low saturation length observed in the samples having the lowest NP areal density. If metal solute may diffuse only within the thermal spike region, for each ion impact, the lateral diffusion distance will be of the order of magnitude of the track size. In the current study, the calculated ion track radius corresponding to the applied ion energies ranges between 3 and 5 nm. Considering the minimum calculated interparticle distance of NPs of about 50 nm, and assuming that the minimum fluence needed for the sample surface overlap is about 1.0 × 1013 ions/cm2 , approximately ten ion impacts within the region are necessary to diffuse over 50 nm. Therefore, the minimum fluence required for solute metal atoms to diffuse from one particle to the nearest one is about 1.0 × 1014 ions/cm2 . The latter accounts quiet well with the fluence necessary to pass from the individual deformation region (*denoted as A*) to the collective deformation process region (*denoted B*) in our results.

suggest that smaller NPs have the tendency to fragmentation and/or disintegration. With the latter in minds, a hypothesis could be that when the minor axis of the aligned nanostructures (nanorods and/or nanowires) is reaching a critical value (maybe in the order of about 8 nm), such nanostructures will disintegrate under subsequent direct ion impact. Due to the parallelism of such nanostructures with the ion beam direction, such ion impact does immediately affect the entire nanowire. Besides, a minimum value for the minor axis of the nanorods and/or nanowires implies that these aligned nanostructures can only be further elongated when atoms from the matrix are collected. In additions, the mutual ion impacts determine which nanowires disintegrate and which grow. In this frame, the NP disintegration and growth are treated as a continuous process, extending also in the region of the collective growth (region B). Eventually, and in view of the decreasing density of the nanowires, the rate of disintegration with fluence decreases and so does the rate of

In this chapter, we have shown that the shape of originally spherical Au NPs embedded in a

swift heavy ion irradiation, spherical Au NPs undergo anisotropic deformation into single prolate nanorod with their long axis parallel to the ion beam direction. Systematic experimental investigation has led to the existence of the so-called threshold fluence for deformation. The extent of the latter has been carried out by variation of both NP size and ion energy. In addition, we have shown that the NP size and areal density have a substantial influence on the characteristics of the ion-induced elongation of confined NPs. In that respect, a well-defined size-dependent NP elongation below a certain irradiation fluence (region A) is identified. In this region, all the NPs elongate following *individual elongation process* depending only on NP

size. Under irradiation with fluence above a certain critical value of 1.00 x 1014 ions/cm2

B at which the deformation is regarded as *collective mechanism* is defined. In this region, longer nanowires are created as a product of several metallic NP contribution to the nanowire growth. Furthermore, in region B, the NP deformation increases with increasing initial NP areal density, i.e., the higher the initial NP areal density is, the longer the nanowires are grown.

[1] Mayer JW. Ion implantation in semiconductors. Electron Devices Meeting, 1973 Inter-

matrix can be modified by swift heavy ion irradiations. Under Ag

, region

Ion-Nanoscale Matter Interactions

33

http://dx.doi.org/10.5772/intechopen.76862

elongation until ultimately a saturation length is reached.

Address all correspondence to<EMAIL_ADDRESS>
**5. Conclusion**

**Author details**

Elmuez A. Dawi

**References**

Ajman University, Ajman, UAE

national, 1973; Vol. 19. pp. 3-5

single plane within a SiO2

Thus, the possibility to grow Au nanowires under swift heavy ion irradiation requires basically the possibility for original NPs to deform and the availability of short-distance solute sources to achieve an effective mass transport. It seems further required that the particles have a certain nanorod shape before the nanowire region is entered or that, alternatively, a certain fluence is applied to enter this region. For Au NPs larger than 30 nm diameter, the mechanism governing nanowire creation requires greater total energy deposition than the value applied here. We note a tendency that the elongation rate diminishes at a higher nanorod length for a higher areal density. For Au NPs of 15 and 30 nm diameter and with increasing irradiation fluence, the minor axis of the elongated nanorods reaches a saturated width at 8 nm. Much in standing with, Giulian et al. [36] report on the elongation process of Pt NPs with size of about 7 nm diameter in a SiO2 matrix. In this study, the minor axis of the elongated Pt NPs is found to reach a saturation at an increasing fluence, while the saturation value of the minor axis increases with increasing the incident in energy. The latter is attributed due to the NP confinement within a well-defined molten track radius in the amorphous SiO2 matrix. On the other hand, Pt NPs with size smaller than 7 nm diameter did not show any sign of deformation but mostly indicate a decrease in size as a result of dissolution. In addition, Au nanocrystals (NCs) [42] with size between 1 and 6 nm diameters further grow in size under SHI irradiation with 100 MeV Au+8 ions to fluences of 5 × 1012 and 2 × 1013 ions/cm2 . These Au NCs were produced by implantation of 4 × 1016 ions/cm2 of the 32 keV Au ion into silica glass. With increasing the irradiation fluence to 1 × 1014 ions/cm2 , the amount of Au nanocrystals retained in the silica matrix dropped to about 20% of its initial value as a result of dissolution. These observations suggest that smaller NPs have the tendency to fragmentation and/or disintegration. With the latter in minds, a hypothesis could be that when the minor axis of the aligned nanostructures (nanorods and/or nanowires) is reaching a critical value (maybe in the order of about 8 nm), such nanostructures will disintegrate under subsequent direct ion impact. Due to the parallelism of such nanostructures with the ion beam direction, such ion impact does immediately affect the entire nanowire. Besides, a minimum value for the minor axis of the nanorods and/or nanowires implies that these aligned nanostructures can only be further elongated when atoms from the matrix are collected. In additions, the mutual ion impacts determine which nanowires disintegrate and which grow. In this frame, the NP disintegration and growth are treated as a continuous process, extending also in the region of the collective growth (region B). Eventually, and in view of the decreasing density of the nanowires, the rate of disintegration with fluence decreases and so does the rate of elongation until ultimately a saturation length is reached.

## **5. Conclusion**

, approxi-

matrix. In this

. These Au

of the 32 keV Au ion into silica glass. With

, the amount of Au nanocrystals retained in the

Some insights can be obtained from **Figure 11(c)** (the inset) and **Figure 14a**, **b** where small fragments are clearly visualized. In fact, those small fragments were not imaged before irradiation; thus, they must be a product of the ion beam irradiation. The energy deposited within the NP subsystem may have allowed the Au atoms and/or species to dissolve in silica. Upon local fluctuation of the solute concentration, the supersaturation of the solid solution then evolves toward the precipitation of the satellite particle phase. Under swift heavy ion irradiation, these small precipitates become unstable [40], and thus they dissolve by subsequent impinging ions (track by track) through the silica matrix. In other words, the diffusion of such nanostructures is driven by the transient melted region formed in the wake of the impinging ions. Dais et al. [41] report on direct observation of the gold diffusion within the ion track. As this process depends on the amount of the available solute sources, i.e., the NP concentration, the lower their relative distance the shorter the diffusion time and the longer the nanowires, as shown in **Figure 13c**, **d** and **Figure 14a**, **b**. On the other hand, when the NP areal density is low, the particle growth is limited by the too long distance between the metal particles. This effect accounts for the relatively low saturation length observed in the samples having the lowest NP areal density. If metal solute may diffuse only within the thermal spike region, for each ion impact, the lateral diffusion distance will be of the order of magnitude of the track size. In the current study, the calculated ion track radius corresponding to the applied ion energies ranges between 3 and 5 nm. Considering the minimum calculated interparticle distance of NPs of about 50 nm, and assuming that the

minimum fluence needed for the sample surface overlap is about 1.0 × 1013 ions/cm2

report on the elongation process of Pt NPs with size of about 7 nm diameter in a SiO2

under SHI irradiation with 100 MeV Au+8 ions to fluences of 5 × 1012 and 2 × 1013 ions/cm2

NCs were produced by implantation of 4 × 1016 ions/cm2

increasing the irradiation fluence to 1 × 1014 ions/cm2

is about 1.0 × 1014 ions/cm2

32 Ion Beam Applications

(*denoted B*) in our results.

amorphous SiO2

mately ten ion impacts within the region are necessary to diffuse over 50 nm. Therefore, the minimum fluence required for solute metal atoms to diffuse from one particle to the nearest one

the individual deformation region (*denoted as A*) to the collective deformation process region

Thus, the possibility to grow Au nanowires under swift heavy ion irradiation requires basically the possibility for original NPs to deform and the availability of short-distance solute sources to achieve an effective mass transport. It seems further required that the particles have a certain nanorod shape before the nanowire region is entered or that, alternatively, a certain fluence is applied to enter this region. For Au NPs larger than 30 nm diameter, the mechanism governing nanowire creation requires greater total energy deposition than the value applied here. We note a tendency that the elongation rate diminishes at a higher nanorod length for a higher areal density. For Au NPs of 15 and 30 nm diameter and with increasing irradiation fluence, the minor axis of the elongated nanorods reaches a saturated width at 8 nm. Much in standing with, Giulian et al. [36]

study, the minor axis of the elongated Pt NPs is found to reach a saturation at an increasing fluence, while the saturation value of the minor axis increases with increasing the incident in energy. The latter is attributed due to the NP confinement within a well-defined molten track radius in the

show any sign of deformation but mostly indicate a decrease in size as a result of dissolution. In addition, Au nanocrystals (NCs) [42] with size between 1 and 6 nm diameters further grow in size

silica matrix dropped to about 20% of its initial value as a result of dissolution. These observations

matrix. On the other hand, Pt NPs with size smaller than 7 nm diameter did not

. The latter accounts quiet well with the fluence necessary to pass from

In this chapter, we have shown that the shape of originally spherical Au NPs embedded in a single plane within a SiO2 matrix can be modified by swift heavy ion irradiations. Under Ag swift heavy ion irradiation, spherical Au NPs undergo anisotropic deformation into single prolate nanorod with their long axis parallel to the ion beam direction. Systematic experimental investigation has led to the existence of the so-called threshold fluence for deformation. The extent of the latter has been carried out by variation of both NP size and ion energy. In addition, we have shown that the NP size and areal density have a substantial influence on the characteristics of the ion-induced elongation of confined NPs. In that respect, a well-defined size-dependent NP elongation below a certain irradiation fluence (region A) is identified. In this region, all the NPs elongate following *individual elongation process* depending only on NP size. Under irradiation with fluence above a certain critical value of 1.00 x 1014 ions/cm2 , region B at which the deformation is regarded as *collective mechanism* is defined. In this region, longer nanowires are created as a product of several metallic NP contribution to the nanowire growth. Furthermore, in region B, the NP deformation increases with increasing initial NP areal density, i.e., the higher the initial NP areal density is, the longer the nanowires are grown.

## **Author details**

Elmuez A. Dawi Address all correspondence to<EMAIL_ADDRESS>Ajman University, Ajman, UAE

## **References**

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[32] Kluth P, Schnohr CS, Sprouster DJ, Byrne AP, Cookson DJ, Ridgway MC. Nuclear

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[38] Trinkaus H. Nuclear Instruments and Methods in Physics Research Section B.

[39] Kluth P, Schnohr CS, Pakarinen OH, Djurabekova F, Sprouster DJ, Giulian R, Ridgway MC, Byrne AP, Trautmann C, Cookson DJ, Nordlund K, Toulemonde M. Physical Review

[40] D'Orléans C, Stoquert JP, Estournès C, Grob JJ, Muller D, Guille JL, Richard-Plouet M, Cerruti C, Haas F. Nuclear Instruments and Methods in Physics Research Section B.2004;

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**Chapter 3**

Provisional chapter

**Ion Beams for Materials Analysis: Conventional and**

DOI: 10.5772/intechopen.76297

Ion beam material diagnostic possibilities are discussed. Experimental data of H+ and He+ ion beams interaction with material for the energy range 0.8–1.6 MeV are presented. There are described the conventional ion beam analytical complex facility and some peculiarities featured for Sokol-3 IMT RAS one. Common characteristics of ion beam analytical methods are described. Specific attention is focused on the ion beam methods use for real objects investigations. It is shown that these methods are very effective for the light element diagnostics. New technology for the element surface analysis on base of the PIXE method modification by the planar X-ray waveguide-resonator application is elaborated. Attention is drowning to facts that all ion beam experimental methods are nondestructive and the Rutherford backscattering spectrometry is real quantitative analytical procedure. Keywords: ion beam, ion beam scattering, Rutherford backscattering, RBS, ions stopping, ion acceleration, ion beam channeling, nuclear reactions, particle-induced X-ray emission, PIXE, ion beam-induced luminescence, depth elements profiles, nuclear elastic recoil spectrometry, vacuum systems, target chamber, X-ray fluorescence yield, X-ray detector

It is well known that the interaction of ion beams—high energy charged particles fluxes with material is accompanied by the complex of specific effects [1]. The interaction with the solid material electron subsystem leads to uniform stopping of high energy charged particles. This interaction is not elastic owing to the atomic ionization effect initiation. Ion collisions with the atomic nuclei can have the elastic as well as inelastic character. Main channels of the interaction are presented in Figure 1. These channels can be used for the nondestructive quantitative analysis of studied target element composition and some features of its structure [2]. In result

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Ion Beams for Materials Analysis: Conventional and

**Advanced Approaches**

Advanced Approaches

Vladimir Egorov and Evgeny Egorov

Vladimir Egorov and Evgeny Egorov

http://dx.doi.org/10.5772/intechopen.76297

Abstract

1. Introduction

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

#### **Ion Beams for Materials Analysis: Conventional and Advanced Approaches** Ion Beams for Materials Analysis: Conventional and Advanced Approaches

DOI: 10.5772/intechopen.76297

Vladimir Egorov and Evgeny Egorov Vladimir Egorov and Evgeny Egorov

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76297

#### Abstract

Ion beam material diagnostic possibilities are discussed. Experimental data of H+ and He+ ion beams interaction with material for the energy range 0.8–1.6 MeV are presented. There are described the conventional ion beam analytical complex facility and some peculiarities featured for Sokol-3 IMT RAS one. Common characteristics of ion beam analytical methods are described. Specific attention is focused on the ion beam methods use for real objects investigations. It is shown that these methods are very effective for the light element diagnostics. New technology for the element surface analysis on base of the PIXE method modification by the planar X-ray waveguide-resonator application is elaborated. Attention is drowning to facts that all ion beam experimental methods are nondestructive and the Rutherford backscattering spectrometry is real quantitative analytical procedure.

Keywords: ion beam, ion beam scattering, Rutherford backscattering, RBS, ions stopping, ion acceleration, ion beam channeling, nuclear reactions, particle-induced X-ray emission, PIXE, ion beam-induced luminescence, depth elements profiles, nuclear elastic recoil spectrometry, vacuum systems, target chamber, X-ray fluorescence yield, X-ray detector

## 1. Introduction

It is well known that the interaction of ion beams—high energy charged particles fluxes with material is accompanied by the complex of specific effects [1]. The interaction with the solid material electron subsystem leads to uniform stopping of high energy charged particles. This interaction is not elastic owing to the atomic ionization effect initiation. Ion collisions with the atomic nuclei can have the elastic as well as inelastic character. Main channels of the interaction are presented in Figure 1. These channels can be used for the nondestructive quantitative analysis of studied target element composition and some features of its structure [2]. In result

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Figure 1. Products of the high energy charged particles interaction with atoms flux.

of the ion beam stopping the material, electron subsystem comes into the excited state. The excited state relaxation can happen by the radiation mechanism through luminescence. The optical luminescence spectra analysis allows to characterize some features of the studied material band structure [3–5]. More high energy relaxation leads to the X-ray characteristic fluorescence irradiation. Collection of X-ray fluorescence spectra is the subject of the particleinduced X-ray emission (PIXE) spectrometry [6–8].

The elastic interaction of high energy ion with atomic nucleus is described by the Rutherford expression, which presents fundamental basis for the Rutherford backscattering (RBS) spectrometry [8–14]. This type of ion-nucleus collision allows to create the nucleus elastic recoil spectrometry [15, 16]. The inelastic ion-nucleus collision leads to the nucleus excitation and the nuclear reaction provoking [17, 18]. Specific peculiarity of the ion-nucleus interaction is the nonRutherford scattering effect [19]. This effect is connected with the increase in time interaction and change in scattering conditions. It must be taken into account to use the proton beam scattering on nuclear of light elements at energy range 0.5–2.0 MeV. In such cases, this effect can be used for the increase in analytical efficiency for the light element diagnostics.

heterostructures [22]. The ion beam channeling is accompanied by the excitation processes efficiency reduction connected with inner atomic electrons of the target. X-ray fluorescence yield intensity excited by high energy beams comes down. At the same time, the intensity of ionoluminescence increases. In the ion beam channeling conditions, the nuclear reaction effi-

Figure 2. The model of He+ ions flux axial channeling through Si monocrystal along [100] crystallographic axis (a) and RBS spectra He+ ions flux for Si crystal in random position about the ion beam propagation direction and in conditions of

Ion Beams for Materials Analysis: Conventional and Advanced Approaches

http://dx.doi.org/10.5772/intechopen.76297

39

Ion beam experimental methods of the material diagnostics are realized by use of ion beams analytical complexes Sokol-3. This complex is in our disposal and will be shortly described in the

Common arrangement of the Sokol-3 units is presented in Figure 3. The Van de Graaff electrostatic generator, which can generate H+ and He+ ion fluxes in the energy range 0.05–2.0 MeV with energy dispersion ΔE = 0.1/0.3 keV, is the most important device of the ion beam analytical complex. The generator allows to vary of the ion beam current magnitude from 0.1 to 50,000 nA (from 6 108 to 3 1013 ions/s) in the beam spot on studied target with diameter 0.1–5 mm. The ion beam current magnitude stability is 3–5%. The analytical complex is equipped by

and experimental chambers is provided by turbomolecular and magnetic-discharge pumps

. The clean vacuum environment in ion guides

ciency and probability of the nuclear recoil effect reduce to a minimum.

2. Experimental setup for ion beam measurements

the vacuum system with total volume near 1 m3

next section.

the ion beam channeling along [100] its axis (b).

The above enumerated techniques based on interaction of chargedparticles beams with substance are indifferent to the material structure peculiarities. At the same time, experimental investigations showed that the monocrystalline and epitaxial targets study by ion beam analytical methods demonstrate specific deviations from results characteristic for polycrystalline and amorphous ones. The monocrystalline structure is characterized by long-range open spaces through the ionsthat can propagate without significant scattering and diminished stopping. Ions can spread to these open channels by glancing collisions with the atoms rows or planes, hereby extending the final ion distribution deeper into target. This effect was called the ion beam channeling, which can be the axial or planar one [20, 21]. The axial channeling of ion beam is visualized inFigure 2. The channeling effect can be used to the trace impurities diagnostics in single crystal and epitaxial targets, the structure defects analysis and for the position determination of impurity atom in the structure. Moreover, this method can allow to define the relative angular orientation of the unit cells axis within the layers of multilayer Ion Beams for Materials Analysis: Conventional and Advanced Approaches http://dx.doi.org/10.5772/intechopen.76297 39

Figure 2. The model of He+ ions flux axial channeling through Si monocrystal along [100] crystallographic axis (a) and RBS spectra He+ ions flux for Si crystal in random position about the ion beam propagation direction and in conditions of the ion beam channeling along [100] its axis (b).

heterostructures [22]. The ion beam channeling is accompanied by the excitation processes efficiency reduction connected with inner atomic electrons of the target. X-ray fluorescence yield intensity excited by high energy beams comes down. At the same time, the intensity of ionoluminescence increases. In the ion beam channeling conditions, the nuclear reaction efficiency and probability of the nuclear recoil effect reduce to a minimum.

Ion beam experimental methods of the material diagnostics are realized by use of ion beams analytical complexes Sokol-3. This complex is in our disposal and will be shortly described in the next section.

## 2. Experimental setup for ion beam measurements

of the ion beam stopping the material, electron subsystem comes into the excited state. The excited state relaxation can happen by the radiation mechanism through luminescence. The optical luminescence spectra analysis allows to characterize some features of the studied material band structure [3–5]. More high energy relaxation leads to the X-ray characteristic fluorescence irradiation. Collection of X-ray fluorescence spectra is the subject of the particle-

The elastic interaction of high energy ion with atomic nucleus is described by the Rutherford expression, which presents fundamental basis for the Rutherford backscattering (RBS) spectrometry [8–14]. This type of ion-nucleus collision allows to create the nucleus elastic recoil spectrometry [15, 16]. The inelastic ion-nucleus collision leads to the nucleus excitation and the nuclear reaction provoking [17, 18]. Specific peculiarity of the ion-nucleus interaction is the nonRutherford scattering effect [19]. This effect is connected with the increase in time interaction and change in scattering conditions. It must be taken into account to use the proton beam scattering on nuclear of light elements at energy range 0.5–2.0 MeV. In such cases, this effect

The above enumerated techniques based on interaction of chargedparticles beams with substance are indifferent to the material structure peculiarities. At the same time, experimental investigations showed that the monocrystalline and epitaxial targets study by ion beam analytical methods demonstrate specific deviations from results characteristic for polycrystalline and amorphous ones. The monocrystalline structure is characterized by long-range open spaces through the ionsthat can propagate without significant scattering and diminished stopping. Ions can spread to these open channels by glancing collisions with the atoms rows or planes, hereby extending the final ion distribution deeper into target. This effect was called the ion beam channeling, which can be the axial or planar one [20, 21]. The axial channeling of ion beam is visualized inFigure 2. The channeling effect can be used to the trace impurities diagnostics in single crystal and epitaxial targets, the structure defects analysis and for the position determination of impurity atom in the structure. Moreover, this method can allow to define the relative angular orientation of the unit cells axis within the layers of multilayer

can be used for the increase in analytical efficiency for the light element diagnostics.

induced X-ray emission (PIXE) spectrometry [6–8].

38 Ion Beam Applications

Figure 1. Products of the high energy charged particles interaction with atoms flux.

Common arrangement of the Sokol-3 units is presented in Figure 3. The Van de Graaff electrostatic generator, which can generate H+ and He+ ion fluxes in the energy range 0.05–2.0 MeV with energy dispersion ΔE = 0.1/0.3 keV, is the most important device of the ion beam analytical complex. The generator allows to vary of the ion beam current magnitude from 0.1 to 50,000 nA (from 6 108 to 3 1013 ions/s) in the beam spot on studied target with diameter 0.1–5 mm. The ion beam current magnitude stability is 3–5%. The analytical complex is equipped by the vacuum system with total volume near 1 m3 . The clean vacuum environment in ion guides and experimental chambers is provided by turbomolecular and magnetic-discharge pumps

Figure 3. Units arrangement of Sokol-3 ion beam analytical complex facility. 1. Van de Graaff accelerator ESU-2; 2. Vaccum ion guide; 3.Analytical electromagnet; 4.RBS chamber; 5.Chamber for nuclear recoil spectrometry; 6.Chamber for PIXE and ionoluminiscence measurements.

quasimonochromatic radiation according to the waveguide-resonance mechanism of radiation flux propagation [25]. The waveguide-resonator showed in Figure 5b is formed by the Be polished reflector and surface of the studied target. The distance between Be reflector and target surface is equal 0.15 μm. Be reflector has the hole for the exciting ion beam propagation to the target. The extended slit clearance formed by Be reflector and target surface captures radiation from the target X-ray fluorescence yield corresponding to the surface atoms fluorescence yield and transports it into SDD X-ray detector. Similar measurement geometry for the surface elements diagnostics at ion beam excitation presents

Figure 5. Experimental chamber for the PIXE conventional measurements (a) and scheme of the modifies PIXE one

allowed to study of the surface element composition (b).

Figure 4. Schematic design of RBS chamber of Sokol-3 analytical complex equipped by two charge particle detectors (a)

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and pattern of application for study of Nb thin film with thickness t=135.20.7 nm on Si substrate (b).

working in a pair with additional use the liquid nitrogen freezing out. In the result, the medium residual pressure in the vacuum system is usually near 1 106 torr (7 104 Pa). At the same time, experimental investigations in the complex chambers are accompanied by C-H film appearing in the ion beam spot. It is connected with great number of the vacuum joints with rubber-like gaskets. Any ion beam analytical complex must be provided by the analytical magnet for the ion beams turning into experimental chambers. Our analytical complex is equipped by three experimental chambers for the RBS, nuclear reaction, and channeling measurements, for the registration of the nuclear recoil effects and for the PIXE and ionoluminescence spectrometry. The Rutherford backscattering is characterized by the original system of the studied target scattered ions registration. It has two detectors for the ions fluxes parallel registration on angles θ1 = 167 and θ2 = 125 to the initial direction of ion beam propagation as shown in Figure 4. Furthermore, the figure presents experimental and theoretical RBS spectra of He+ ions for Nb/Si target obtained for the angles pointed above. It is very important that two independent RBS spectra represent the target element distribution. The spectra approximation carried out by RUMPP computer program built on base of the RUMP software modification [23] allowed to obtained the target depth element concentration profile. The depth element profile of this target is very simple and the double detector registration system application in this case has an excessive character. But the approximation of two RBS spectra allowed to increase precision of the Nb thin film thickness. Application of two detector systems for RBS investigations and for registration of the nuclear reaction products allows to avoid possible errors at the experimental data interpretation.

We used the original construction for the PIXE measurements modification. Figure 5a presents chamber for conventional PIXE measurements execution. The conventional PIXE spectrometry allows to characterize the volume element composition of studied target. The method modification by application of the planar X-ray waveguide-resonator (PXWR) presents possibilities of the target surface element composition study [24]. Figure 5b shows the measurement scheme dedicated for the surface element study. PXWR can transport X-ray

Ion Beams for Materials Analysis: Conventional and Advanced Approaches http://dx.doi.org/10.5772/intechopen.76297 41

Figure 4. Schematic design of RBS chamber of Sokol-3 analytical complex equipped by two charge particle detectors (a) and pattern of application for study of Nb thin film with thickness t=135.20.7 nm on Si substrate (b).

quasimonochromatic radiation according to the waveguide-resonance mechanism of radiation flux propagation [25]. The waveguide-resonator showed in Figure 5b is formed by the Be polished reflector and surface of the studied target. The distance between Be reflector and target surface is equal 0.15 μm. Be reflector has the hole for the exciting ion beam propagation to the target. The extended slit clearance formed by Be reflector and target surface captures radiation from the target X-ray fluorescence yield corresponding to the surface atoms fluorescence yield and transports it into SDD X-ray detector. Similar measurement geometry for the surface elements diagnostics at ion beam excitation presents

working in a pair with additional use the liquid nitrogen freezing out. In the result, the medium residual pressure in the vacuum system is usually near 1 106 torr (7 104 Pa). At the same time, experimental investigations in the complex chambers are accompanied by C-H film appearing in the ion beam spot. It is connected with great number of the vacuum joints with rubber-like gaskets. Any ion beam analytical complex must be provided by the analytical magnet for the ion beams turning into experimental chambers. Our analytical complex is equipped by three experimental chambers for the RBS, nuclear reaction, and channeling measurements, for the registration of the nuclear recoil effects and for the PIXE and ionoluminescence spectrometry. The Rutherford backscattering is characterized by the original system of the studied target scattered ions registration. It has two detectors for the ions fluxes parallel registration on angles θ1 = 167 and θ2 = 125 to the initial direction of ion beam propagation as shown in Figure 4. Furthermore, the figure presents experimental and theoretical RBS spectra

Figure 3. Units arrangement of Sokol-3 ion beam analytical complex facility. 1. Van de Graaff accelerator ESU-2; 2. Vaccum ion guide; 3.Analytical electromagnet; 4.RBS chamber; 5.Chamber for nuclear recoil spectrometry; 6.Chamber

ions for Nb/Si target obtained for the angles pointed above. It is very important that two independent RBS spectra represent the target element distribution. The spectra approximation carried out by RUMPP computer program built on base of the RUMP software modification [23] allowed to obtained the target depth element concentration profile. The depth element profile of this target is very simple and the double detector registration system application in this case has an excessive character. But the approximation of two RBS spectra allowed to increase precision of the Nb thin film thickness. Application of two detector systems for RBS investigations and for registration of the nuclear reaction products allows to avoid possible

We used the original construction for the PIXE measurements modification. Figure 5a presents chamber for conventional PIXE measurements execution. The conventional PIXE spectrometry allows to characterize the volume element composition of studied target. The method modification by application of the planar X-ray waveguide-resonator (PXWR) presents possibilities of the target surface element composition study [24]. Figure 5b shows the measurement scheme dedicated for the surface element study. PXWR can transport X-ray

of He+

errors at the experimental data interpretation.

for PIXE and ionoluminiscence measurements.

40 Ion Beam Applications

Figure 5. Experimental chamber for the PIXE conventional measurements (a) and scheme of the modifies PIXE one allowed to study of the surface element composition (b).

There is discussed the "backscattering" situation because the kinematical factor maximum

Probability of the ion-nucleus collision is defined by the Rutherford famous formula in form of the scattering average differential cross-section σ, which can be presented in the laboratory

where x is M1/M2 relation, Z1 and Z2 are changes of ion and nucleus, e is the electron charge and E is the ion pre-collision energy. The charge particle detector registers the total particles quantity Ai, which defines by the collision cross-section, the total quantity of charged particles interacted with the studied target q, the detector spatial angle Ω, the volume atomic concentration Ni and the layer thickness t connected with the RBS spectrum discreteness degree and

Total Rutherford backscattering spectrum presents aggregate of similar magnitudes outlined in the diagrammatic form. Sample of this similar diagram is shown in Figure 7. RBS spectra of He+ and H+ ion beams obtained for the SrTiO3 stoichiometric target are presented. These spectra are diagrams reflecting dependences of the ion beams scattering yield on the energy of scattering particles. Every channel of the diagrams reflects the ions number scattering on nuclei the target atoms (Eq. (3)). An energy scales of the spectra are connected with the depth

are approximated by RUMPP program and the theoretical spectra are superposed with experimental ones. The arrows designate the scattering energies corresponding to atoms on the target surface. The measurement geometry is shown on

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 � x2sin2 θ p þ cosθ sin4θ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 � x2sin2

θ p (2)

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Ion Beams for Materials Analysis: Conventional and Advanced Approaches

Ai ¼ qΩσNit (3)

(b)ion beams obtained for the SrTiO3 stoichiometric target. Experimental spectra

magnitude is obtained for θ near 180�. In this case, we have the best mass resolution.

σ ¼ Z1Z2e2 2E

coordinates system by the next expression [8]:

can be presented by the expression [8]:

Figure 7. RBS spectra of He+ (a) and H+

the inserts. The energy step is 1.9 keV/channel.

Figure 6. Schemes of experimental setups for yield registration of the light luminescence from the studied target at ion beam excitation (a) and for the target parallel investigation by RBS and the elastic nuclear recoil methods (b).

new experimental method, which was named as the total X-ray reflection fluorescence at particle excitation (TXRF PE).

Figure 6 shows the experimental chamber arrangement for the ionoluminescence and the nuclear recoil spectrometry. These investigation methods are realized in frame of the Sokol-3 facility in conventional arrangement.

Experimental investigations of the ion beam channeling can be executed in any chambers of the analytical complex. But most part of these experiments is carried out by using the RBS chamber.

## 3. Rutherford backscattering spectrometry as the basic method of material ion beam diagnostics

#### 3.1. Common principles of the method

The Rutherford backscattering conception is based on possibility of the energy losses direct calculation for ion beams interacting with electron and atomic nuclear material subsystems. The energy redistribution in the ion-nucleus collision is defined by the kinematical factor expression [10]:

$$E\_1 = E\_0 \left[ \frac{\sqrt{M\_2^2 - M\_1^2 \sin^2 \theta} + M\_1 \cos \theta}{M\_1 + M\_2} \right] \tag{1}$$

where E0 and E1 are energies of ion pre- and post-collision, M1 and M2are masses of ion and nucleus accordingly and θ is the angle of ion deviation from its initial propagation direction. There is discussed the "backscattering" situation because the kinematical factor maximum magnitude is obtained for θ near 180�. In this case, we have the best mass resolution.

Probability of the ion-nucleus collision is defined by the Rutherford famous formula in form of the scattering average differential cross-section σ, which can be presented in the laboratory coordinates system by the next expression [8]:

$$\sigma = \frac{Z\_1 Z\_2 \varepsilon^2}{2E} \frac{\sqrt{1 - \mathbf{x}^2 \sin^2 \theta} + \cos \theta}{\sin^4 \theta \sqrt{1 - \mathbf{x}^2 \sin^2 \theta}} \tag{2}$$

where x is M1/M2 relation, Z1 and Z2 are changes of ion and nucleus, e is the electron charge and E is the ion pre-collision energy. The charge particle detector registers the total particles quantity Ai, which defines by the collision cross-section, the total quantity of charged particles interacted with the studied target q, the detector spatial angle Ω, the volume atomic concentration Ni and the layer thickness t connected with the RBS spectrum discreteness degree and can be presented by the expression [8]:

$$A\_i = q \Omega \sigma N\_i t \tag{3}$$

Total Rutherford backscattering spectrum presents aggregate of similar magnitudes outlined in the diagrammatic form. Sample of this similar diagram is shown in Figure 7. RBS spectra of He+ and H+ ion beams obtained for the SrTiO3 stoichiometric target are presented. These spectra are diagrams reflecting dependences of the ion beams scattering yield on the energy of scattering particles. Every channel of the diagrams reflects the ions number scattering on nuclei the target atoms (Eq. (3)). An energy scales of the spectra are connected with the depth

new experimental method, which was named as the total X-ray reflection fluorescence at

Figure 6. Schemes of experimental setups for yield registration of the light luminescence from the studied target at ion

beam excitation (a) and for the target parallel investigation by RBS and the elastic nuclear recoil methods (b).

Figure 6 shows the experimental chamber arrangement for the ionoluminescence and the nuclear recoil spectrometry. These investigation methods are realized in frame of the Sokol-3

Experimental investigations of the ion beam channeling can be executed in any chambers of the analytical complex. But most part of these experiments is carried out by using the RBS chamber.

3. Rutherford backscattering spectrometry as the basic method of material

The Rutherford backscattering conception is based on possibility of the energy losses direct calculation for ion beams interacting with electron and atomic nuclear material subsystems. The energy redistribution in the ion-nucleus collision is defined by the kinematical factor

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

where E0 and E1 are energies of ion pre- and post-collision, M1 and M2are masses of ion and nucleus accordingly and θ is the angle of ion deviation from its initial propagation direction.

1sin2θ

M1 þ M2

þ M1cosθ

3

5 (1)

M2 2 � M2

q

2 4

particle excitation (TXRF PE).

42 Ion Beam Applications

ion beam diagnostics

expression [10]:

facility in conventional arrangement.

3.1. Common principles of the method

E1 ¼ E0

Figure 7. RBS spectra of He+ (a) and H+ (b)ion beams obtained for the SrTiO3 stoichiometric target. Experimental spectra are approximated by RUMPP program and the theoretical spectra are superposed with experimental ones. The arrows designate the scattering energies corresponding to atoms on the target surface. The measurement geometry is shown on the inserts. The energy step is 1.9 keV/channel.

elements distribution profile for the studied target. The scattering energy for surface atoms is defined by the kinematical factor, only. These energies are connected to steps edges of the diagrams. The scattering description of ion beams on nuclei of the internal atoms demands taking into account the ions stopping as pre- and post-scattering act. The stopping energy losses ΔE on the distance Δx are usually described by the Bohr formula:

$$-\frac{\Delta E}{\Delta x} = \frac{4\pi Z\_1^2 e^4 n}{m\upsilon^2} \ln \frac{2m\upsilon^2}{I} \tag{4}$$

where Z1 and v are the charge and velocity of the stopping ion, e and m are the charge and mass of electron and n is the studied material electron density. I is the ion average energy loss for the electron excitation (near 30 eV). I and n parameters are not constants and depend from very much factors. As a result, the decision was made to present the stopping losses in the tabular form [26]. This approach allowed to calculate the energy losses by introduction of the ½ � ε effective stopping cross-section accordingly to the expression [27].

$$
\Delta E = [\overline{\varepsilon}] \mathcal{N} t \tag{5}
$$

where N is the atomic density (atoms/cm3 ). In case of the multielement material, the stopping cross-section is defined accordingly to the Bragg rule:

$$
\varepsilon^{AmBan} = m\varepsilon^A + n\varepsilon^B \tag{6}
$$

near 20 nm. Last parameter was evaluated on base of the steepness evaluation of step increasing for Hf(Sr, Ti) partial spectrum in comparison with this parameter for the Nb/Si standard target with roughness smaller 5 nm. The surface roughness Δr can be evaluated by the next

Figure 9. Experimental and theoretical RBS He+ and H+ ions spectra for the Hf/Cr/Al multilayer target. Arrows show the ion scattering energy on nuclei of atoms located on the target surface. Measurement geometry is shown on inserts. Energy

Figure 8. Experimental and theoretical RBS He+ ions (E0 = 1.24 MeV) spectra for the SrTiO3/SiO2/Si thin film structure. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is

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where ΔEexp is the half width of the curve obtained as a result of the step rise steepness differentiation, ΔEd is the detector energy resolution, Nt is the target atomic density and ½ � ε is the average value of the target atomic cross-section. Comparison of the RBS spectra obtained

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ΔE2

exp � ΔE2 d

Nt½ � ε (7)

Δr ¼

q

expression [10]:

step 1.9 keV/channel.

shown on insert. Energy step 1.9 keV/channel.

Accuracy of tabular magnitudes for the material stopping cross-section is limited by value near 1%. In the result, the material parameters determination accuracy cannot be better of this value. In the practical work, the stopping cross-section data are fed into a computer program providing the RBS spectra approximation [23, 27]. As a result, we have that every channel of the spectrum is connected with a planar layer of the target with thickness t and average element concentration N. The rise steepness of steps in the RBS spectrum is defined by the detector energy resolution used for the spectrum registration. The resolution of He+ ions scattering fluxes is near 10 keV thatcorresponds to the depth resolution 10–12 nm at the ion beam vertical incidence on the studied target and up to 2 nm at the sliding incidence.

The Rutherford backscattering spectrometry is very effective method of the thin film structure analysis. Figure 8 demonstrates experimental and theoretical spectra of RBS He+ ion beam for SrTiO3 thin film on the silicon substrate with oxidizing layer. The experimental spectrum theoretical approximation showed that the film is characterized by the stoichiometric composition with thickness t = 230 nm. Theoretical approximation of the spectrum did not involve some difficulties, because the film material contained elements with high atomic masses, and substrate, on the contrary, contained light elements. Similar situation can be observed in Figure 9. It demonstrates experimental and theoretical RBS of He+ and H+ ion beams spectra for the Hf/Cr/Al multilayer target. Theoretical approximation of these spectra showed that the Hf film had thickness t = 120 � 5 nm and contained 11% of Sr atoms and 14% of Ti atoms. Cr film had not admixture. It was characterized by the thickness t = 40 � 7 nm. Interdiffusion zone between these films had the thickness near 25 nm. The surface roughness of the coating was Ion Beams for Materials Analysis: Conventional and Advanced Approaches http://dx.doi.org/10.5772/intechopen.76297 45

elements distribution profile for the studied target. The scattering energy for surface atoms is defined by the kinematical factor, only. These energies are connected to steps edges of the diagrams. The scattering description of ion beams on nuclei of the internal atoms demands taking into account the ions stopping as pre- and post-scattering act. The stopping energy

> 1e4n mv2 ln 2mv2

where Z1 and v are the charge and velocity of the stopping ion, e and m are the charge and mass of electron and n is the studied material electron density. I is the ion average energy loss for the electron excitation (near 30 eV). I and n parameters are not constants and depend from very much factors. As a result, the decision was made to present the stopping losses in the tabular form [26]. This approach allowed to calculate the energy losses by introduction of the

Accuracy of tabular magnitudes for the material stopping cross-section is limited by value near 1%. In the result, the material parameters determination accuracy cannot be better of this value. In the practical work, the stopping cross-section data are fed into a computer program providing the RBS spectra approximation [23, 27]. As a result, we have that every channel of the spectrum is connected with a planar layer of the target with thickness t and average element concentration N. The rise steepness of steps in the RBS spectrum is defined by the detector energy resolution used for the spectrum registration. The resolution of He+ ions scattering fluxes is near 10 keV thatcorresponds to the depth resolution 10–12 nm at the ion

beam vertical incidence on the studied target and up to 2 nm at the sliding incidence.

The Rutherford backscattering spectrometry is very effective method of the thin film structure analysis. Figure 8 demonstrates experimental and theoretical spectra of RBS He+ ion beam for SrTiO3 thin film on the silicon substrate with oxidizing layer. The experimental spectrum theoretical approximation showed that the film is characterized by the stoichiometric composition with thickness t = 230 nm. Theoretical approximation of the spectrum did not involve some difficulties, because the film material contained elements with high atomic masses, and substrate, on the contrary, contained light elements. Similar situation can be observed in Figure 9. It demonstrates experimental and theoretical RBS of He+ and H+ ion beams spectra for the Hf/Cr/Al multilayer target. Theoretical approximation of these spectra showed that the Hf film had thickness t = 120 � 5 nm and contained 11% of Sr atoms and 14% of Ti atoms. Cr film had not admixture. It was characterized by the thickness t = 40 � 7 nm. Interdiffusion zone between these films had the thickness near 25 nm. The surface roughness of the coating was

I (4)

ΔE ¼ ½ � ε Nt (5)

). In case of the multielement material, the stopping

εAmBn ¼ mεA þ nεB (6)

losses ΔE on the distance Δx are usually described by the Bohr formula:

½ � ε effective stopping cross-section accordingly to the expression [27].

where N is the atomic density (atoms/cm3

44 Ion Beam Applications

cross-section is defined accordingly to the Bragg rule:

� ΔE

Δx ¼ 4πZ2

Figure 8. Experimental and theoretical RBS He+ ions (E0 = 1.24 MeV) spectra for the SrTiO3/SiO2/Si thin film structure. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

Figure 9. Experimental and theoretical RBS He+ and H+ ions spectra for the Hf/Cr/Al multilayer target. Arrows show the ion scattering energy on nuclei of atoms located on the target surface. Measurement geometry is shown on inserts. Energy step 1.9 keV/channel.

near 20 nm. Last parameter was evaluated on base of the steepness evaluation of step increasing for Hf(Sr, Ti) partial spectrum in comparison with this parameter for the Nb/Si standard target with roughness smaller 5 nm. The surface roughness Δr can be evaluated by the next expression [10]:

$$
\Delta r = \frac{\sqrt{\Delta E\_{\text{exp}}^2 - \Delta E\_d^2}}{N\_t[\overline{\varepsilon}]} \tag{7}
$$

where ΔEexp is the half width of the curve obtained as a result of the step rise steepness differentiation, ΔEd is the detector energy resolution, Nt is the target atomic density and ½ � ε is the average value of the target atomic cross-section. Comparison of the RBS spectra obtained for the same object shows that the He+ ion beam application allows to have the better resolution and the H+ ion beam use takes possibilities to test object on the more depth.

#### 3.2. Possibilities of the RBS elements diagnostics

The RBS investigations of target with the heavy elements high content have evident problems. Figure 10 presents RBS H+ and He+ ions beam spectra for the W0.45C0.43C0.12 target characterized by the tungsten atoms high concentration. The scattering cross-section of ions on the W nuclei is higher in comparison with these parameters for C and Co atomic nuclei. The alloy target composition had been gained in the result of the four spectra joint approximation obtained for He+ and H+ ion scattering beams collected for θ1 = 167 and θ2 = 125. The nonRutherford scattering effect was taken into account in the calculation. Owing to the necessity of this effect inclusion, specific investigation were executed [18, 19]. Sample of similar investigations of 12C6 nucleus nonRutherford scattering factor is presented in Figure 11. Comparison of the Rutherford scattering cross-section and magnitudes of this parameter obtained in the experiments shows a great difference especially for the energy E = 1735 keV. The nonRutherford scattering factor value depends on the registration angle, and it is a need to get the factor experimental data for the selected measurement conditions. Similar work of the nonRutherford factor determination for carbon and boron atoms was executed preparatory to approximate RBS spectrum presented in Figure 12. The approximation of this spectrum is not simple procedure. Chief problem of the approximation is connected with the nonRutherford factors energy variation for carbon and boron atoms. The approximation result is presented in the table. Total thickness of the coating is 1.75 μm. Including the second RBS spectrum into approximation procedure does not improve the final result because this procedure demands additional investigations for receiving the nonRutherford factors energy dependences for the additional scattering angle. At the same time, the nonRutherford factor can be very useful for the

Figure 10. Experimental and theoretical RBS He+ and H+ ions spectra for the W0.45C0.43Co0.12 high temperature alloy. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on inserts. Energy step 1.9 keV/channel.

targets study containing light element. As the sample, RBS spectra of the polished beryllium disk are presented in Figure 13. The spectrum of the He+ ions scattering in selected energy range does not distort by the nonRutherford factor. It shows that the target possesses the surface oxide film

Figure 12. Experimental and theoretical RBS H+ ions (E0 = 1.085 MeV) spectra for Ti-B-C film deposited on Si substrate in result of the Ti2CB10 sample magnetron sputtering (a) and table with the approximation results. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on insert. Energy

Figure 11. Theoretical and experimental energy dependences of H+ ion beam scattering cross-section on 12C nuclei for the

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collection angle θ = 167.

step 1.9 keV/channel.

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for the same object shows that the He+ ion beam application allows to have the better resolu-

The RBS investigations of target with the heavy elements high content have evident problems. Figure 10 presents RBS H+ and He+ ions beam spectra for the W0.45C0.43C0.12 target characterized by the tungsten atoms high concentration. The scattering cross-section of ions on the W nuclei is higher in comparison with these parameters for C and Co atomic nuclei. The alloy target composition had been gained in the result of the four spectra joint approximation obtained for He+ and H+ ion scattering beams collected for θ1 = 167 and θ2 = 125. The nonRutherford scattering effect was taken into account in the calculation. Owing to the necessity of this effect inclusion, specific investigation were executed [18, 19]. Sample of similar investigations of 12C6 nucleus nonRutherford scattering factor is presented in Figure 11. Comparison of the Rutherford scattering cross-section and magnitudes of this parameter obtained in the experiments shows a great difference especially for the energy E = 1735 keV. The nonRutherford scattering factor value depends on the registration angle, and it is a need to get the factor experimental data for the selected measurement conditions. Similar work of the nonRutherford factor determination for carbon and boron atoms was executed preparatory to approximate RBS spectrum presented in Figure 12. The approximation of this spectrum is not simple procedure. Chief problem of the approximation is connected with the nonRutherford factors energy variation for carbon and boron atoms. The approximation result is presented in the table. Total thickness of the coating is 1.75 μm. Including the second RBS spectrum into approximation procedure does not improve the final result because this procedure demands additional investigations for receiving the nonRutherford factors energy dependences for the additional scattering angle. At the same time, the nonRutherford factor can be very useful for the

Figure 10. Experimental and theoretical RBS He+ and H+ ions spectra for the W0.45C0.43Co0.12 high temperature alloy. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is

shown on inserts. Energy step 1.9 keV/channel.

tion and the H+ ion beam use takes possibilities to test object on the more depth.

3.2. Possibilities of the RBS elements diagnostics

46 Ion Beam Applications

Figure 11. Theoretical and experimental energy dependences of H+ ion beam scattering cross-section on 12C nuclei for the collection angle θ = 167.

Figure 12. Experimental and theoretical RBS H+ ions (E0 = 1.085 MeV) spectra for Ti-B-C film deposited on Si substrate in result of the Ti2CB10 sample magnetron sputtering (a) and table with the approximation results. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

targets study containing light element. As the sample, RBS spectra of the polished beryllium disk are presented in Figure 13. The spectrum of the He+ ions scattering in selected energy range does not distort by the nonRutherford factor. It shows that the target possesses the surface oxide film

Figure 13. Experimental and theoretical RBS He+ and H+ ions for the polished Be disk. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on inserts. Energy step 3.8 keV/channel.

with thickness near 10 nm and the carbon hydrogen snuff with similar thickness appearing in result of the ion bombardment. The beryllium material contains 5% of the oxygen atoms, 0.1% of the iron atoms and 0.002% of the tungsten atoms. RBS spectrum of H+ ions confirms these results. But its approximation is more difficult and it does not show the oxide film on the disk surface. At the same time, its registration time is more short in comparison with the He+ spectrum collection.

Be polished disks can serve beautiful substrates for study of the solution dry residues and structures prepared by the specific procedure. Sample of the similar investigation is presented in Figure 14. This target is studied by RBS method and by application of the elastic nuclear recoil spectrometry. The main element composition of the petroleum film is H0.07C0.90S0.028N0.002. The film admixture composition defined by PIXE method will be discussed below. RBS spectrometry can be used for the medical preparation element diagnostics. Figure 15 shows experimental and theoretical of RBS spectra for the solution dry residue of pantocrine in form of the film on Be substrate. The element composition knowledge is not chief problem for the pharmacology, but RBS, PIXE and nuclear reaction analysis can help for the specific element diagnostics of medical preparations.

Figure 16 shows experimental and theoretical RBS spectra for the graphene oxide film deposited on the Be substrate in the hydrothermal conditions. The technology of the grapheme oxide preparation is not perfect. As a result, the film contains Na and Ca atoms in the macro concentration. At the same time, RBS measurements allow to control the admixtures macro concentration presence and the film constitution. RBS method is useful for the target study containing other light element. Figure 17 presents experimental and theoretical RBS He+ and H+ ions spectra for the hexagonal BN target. Mathematical approximation of the spectra shows

that the surface layer of the target has the boron increasing concentration. The spectrum of H+

Figure 15. Experimental and theoretical RBS He+ (E0 = 1.52 MeV) ions spectra for the dry residue of pantocrine (DRP) aqueous solution on Be substrate. Arrows show the ion scattering energies on nuclei of atoms located on the dry residue film surface. Measurement geometrics and the pantocrine element compositions are presented on inserts. Energy step

Figure 14. Experimental and theoretical RBS H+ ions (E0= 0.953 MeV) spectra characterizing the petroleum film on Be substrate. Film composition is H0.07C0.9S0.028N0.002 (on mains elements). Arrows show the ion scattering energies on nuclei

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of atoms located on the film surface. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

reaction course. The approximation has some problem in the context of 10B5 and 11B5 boron two isotopes existence in comparison concentrations. Every isotope is characterized by its own

8

Be nuclear

ions scattering showed that the scattering process is accompanied by the 11B(p,α)

3.8 keV/channel.

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Figure 14. Experimental and theoretical RBS H+ ions (E0= 0.953 MeV) spectra characterizing the petroleum film on Be substrate. Film composition is H0.07C0.9S0.028N0.002 (on mains elements). Arrows show the ion scattering energies on nuclei of atoms located on the film surface. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

with thickness near 10 nm and the carbon hydrogen snuff with similar thickness appearing in result of the ion bombardment. The beryllium material contains 5% of the oxygen atoms, 0.1% of the iron atoms and 0.002% of the tungsten atoms. RBS spectrum of H+ ions confirms these results. But its approximation is more difficult and it does not show the oxide film on the disk surface. At the same time, its registration time is more short in comparison with the He+ spectrum collection.

Figure 13. Experimental and theoretical RBS He+ and H+ ions for the polished Be disk. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on inserts. Energy step 3.8

Be polished disks can serve beautiful substrates for study of the solution dry residues and structures prepared by the specific procedure. Sample of the similar investigation is presented in Figure 14. This target is studied by RBS method and by application of the elastic nuclear recoil spectrometry. The main element composition of the petroleum film is H0.07C0.90S0.028N0.002. The film admixture composition defined by PIXE method will be discussed below. RBS spectrometry can be used for the medical preparation element diagnostics. Figure 15 shows experimental and theoretical of RBS spectra for the solution dry residue of pantocrine in form of the film on Be substrate. The element composition knowledge is not chief problem for the pharmacology, but RBS, PIXE and nuclear reaction analysis can help for the specific element diagnostics of medical

Figure 16 shows experimental and theoretical RBS spectra for the graphene oxide film deposited on the Be substrate in the hydrothermal conditions. The technology of the grapheme oxide preparation is not perfect. As a result, the film contains Na and Ca atoms in the macro concentration. At the same time, RBS measurements allow to control the admixtures macro concentration presence and the film constitution. RBS method is useful for the target study containing other light element. Figure 17 presents experimental and theoretical RBS He+ and H+ ions spectra for the hexagonal BN target. Mathematical approximation of the spectra shows

preparations.

keV/channel.

48 Ion Beam Applications

Figure 15. Experimental and theoretical RBS He+ (E0 = 1.52 MeV) ions spectra for the dry residue of pantocrine (DRP) aqueous solution on Be substrate. Arrows show the ion scattering energies on nuclei of atoms located on the dry residue film surface. Measurement geometrics and the pantocrine element compositions are presented on inserts. Energy step 3.8 keV/channel.

that the surface layer of the target has the boron increasing concentration. The spectrum of H+ ions scattering showed that the scattering process is accompanied by the 11B(p,α) 8 Be nuclear reaction course. The approximation has some problem in the context of 10B5 and 11B5 boron two isotopes existence in comparison concentrations. Every isotope is characterized by its own

Figure 16. Experimental and theoretical RBS H+ (E0 = 1.005 MeV) spectra for the graphene oxide film deposited on the beryllium substrate in hydrothermal conditions. Arrows show the ion scattering energies on nuclei of atoms located on the film surface. Measurement geometries and the film parameters are presented on insert. Energy step 1.9 keV/channel.

nonRutherford factors for the proton beam scattering. The nuclear reaction existence can be

thickness t = 12 nm appeared during of the measurements process. Arrows show the ion scattering energies on nuclei of

atoms located on the target surface. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

ions spectra for the LiF natural specimen. Surface carbon film with

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The Rutherford spectrometry can help to analyze the lithium atoms presence in materials. Figure 18 shows RBS spectrum for the LiF stoichiometric target. This approximation required the nonRutherford data collection in the selected energy range for the H+ ion beam scattering on Li and F atomic nuclei. But owing to the nonRutherford factor for Li, N, O and F atomic nuclei is not great the diagnostic of its atoms in targets with high concentration of heavy atoms presents some difficulties (see Figure 10). PIXE and ion beam channeling methods can help in

Study of atomic diffusion peculiarities in solid material is the main branch of the solid state physics [28]. The wide use of thin material films has direct relation to study the material transport in thin films and coatings, since the density of short-circuit diffusion paths, especially grain boundaries (GBs) in its compositions is higher as compared with massive materials [29]. In our work, we used RBS spectrometry possibilities for the interdiffusion study in the Au/Cu bimetallic structure. Figure 19 presents RBS He+ spectra of the bimetallic structure pre and post treatment used different thermal actions [30]. At the long thermo treatment, the main interdiffusion mechanism was connected with the bulk diffusion (Figure 19a). In this case, the Au/Cu interface disappears and the intermediate layer arises. In case of the short high temperature treatment, we can see the copper atoms on the target surface, and Au atom from the initial interface dissolves in the Cu film. As a result, it is possible to obtain bulk and GB diffusion factors for different bimetallic combinations and to evaluate magnitudes of the possible segregation effect [31]. Particular significance for the diffusion practice can have the

used for the boron concentration diagnostics in materials.

element isotopic investigation with the nuclear reaction application.

3.3. Atomic diffusion study by RBS method

Figure 18. Experimental and theoretical RBS H+

this problem solution.

Figure 17. Experimental and theoretical RBS He+ and H+ ions (E0 = 1.5 MeV) spectra for the Boron-Nitrogen target prepared by chemical exfoliation method in form of the free plate. Arrows show the ion scattering energies on nuclei of atoms located on the plate surface. Measurement geometry is shown on insert. Energy step 3.8 keV/channel.

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Figure 18. Experimental and theoretical RBS H+ ions spectra for the LiF natural specimen. Surface carbon film with thickness t = 12 nm appeared during of the measurements process. Arrows show the ion scattering energies on nuclei of atoms located on the target surface. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

nonRutherford factors for the proton beam scattering. The nuclear reaction existence can be used for the boron concentration diagnostics in materials.

The Rutherford spectrometry can help to analyze the lithium atoms presence in materials. Figure 18 shows RBS spectrum for the LiF stoichiometric target. This approximation required the nonRutherford data collection in the selected energy range for the H+ ion beam scattering on Li and F atomic nuclei. But owing to the nonRutherford factor for Li, N, O and F atomic nuclei is not great the diagnostic of its atoms in targets with high concentration of heavy atoms presents some difficulties (see Figure 10). PIXE and ion beam channeling methods can help in this problem solution.

#### 3.3. Atomic diffusion study by RBS method

Figure 16. Experimental and theoretical RBS H+ (E0 = 1.005 MeV) spectra for the graphene oxide film deposited on the beryllium substrate in hydrothermal conditions. Arrows show the ion scattering energies on nuclei of atoms located on the film surface. Measurement geometries and the film parameters are presented on insert. Energy step 1.9 keV/channel.

50 Ion Beam Applications

Figure 17. Experimental and theoretical RBS He+ and H+ ions (E0 = 1.5 MeV) spectra for the Boron-Nitrogen target prepared by chemical exfoliation method in form of the free plate. Arrows show the ion scattering energies on nuclei of

atoms located on the plate surface. Measurement geometry is shown on insert. Energy step 3.8 keV/channel.

Study of atomic diffusion peculiarities in solid material is the main branch of the solid state physics [28]. The wide use of thin material films has direct relation to study the material transport in thin films and coatings, since the density of short-circuit diffusion paths, especially grain boundaries (GBs) in its compositions is higher as compared with massive materials [29]. In our work, we used RBS spectrometry possibilities for the interdiffusion study in the Au/Cu bimetallic structure. Figure 19 presents RBS He+ spectra of the bimetallic structure pre and post treatment used different thermal actions [30]. At the long thermo treatment, the main interdiffusion mechanism was connected with the bulk diffusion (Figure 19a). In this case, the Au/Cu interface disappears and the intermediate layer arises. In case of the short high temperature treatment, we can see the copper atoms on the target surface, and Au atom from the initial interface dissolves in the Cu film. As a result, it is possible to obtain bulk and GB diffusion factors for different bimetallic combinations and to evaluate magnitudes of the possible segregation effect [31]. Particular significance for the diffusion practice can have the element isotopic investigation with the nuclear reaction application.

expected effect takes place, really. RBS H+ ions spectra for the diamond crystal and for the glass carbon sample are not equivalent. The diamond structure is characterized by a more compact atomic packing and demonstrated the enhanced scattering yield in the RBS spectrum. Its effect can be used for study of the porous structures. Figure 21 shows the sample of the Rutherford backscattering study of the Al film in conditions after its preparation and in the result of thermal treatment [32]. Initial spectrum demonstrates the smaller scattering intensity yield in comparison with the theoretical spectrum (a). It is connected with the structure vacancy concentration near 6%. The thermal treatment let to the Al film, thickness decreasing from 300 to 284 nm (see the diagram (c)). The comparison of initial and finishing experimental spectra demonstrates the thickness decreasing and the atomic density increasing up to the normal structure value. Similar investigations is very important because the thin film prepara-

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The material atomic density variation can be connected with not only the structural vacancy appearing. Material in the nanostructure state is characterized by the increase in interatomic distance [33]. Figure 22 demonstrates the Rutherford backscattering yield decreasing for the Ag thin films deposited on the silicon substrate. There are presented two RBS He+ (E0 = 1.27 MeV) ions spectra collected by our double detector system (θ1 = 160, θ2 = 120). Theoretical approximation of these spectra showed that the Ag film thickness is equal 48 nm but the evident discrepancy between Ag theoretical and experimental partial spectra was discovered. In this case, it was nearly equal to 6%. Moreover, the discrepancy increases as the Ag film became more slender and disappears when it will be large 100 nm. Our diffraction measurements confirmed supposition about the atomic density decreasing as aresult of the interatomic distance growth. Similar RBS investigations can be very useful for the material atomic density

Figure 21. Experimental and theoretical RBS He+ (E0 = 1.5 MeV) ions for Al/SiO2 structure pre (a) and post-thermal treatment (b) and the experimental diagram of the Al thin film thickness variation in result of the thermal treatment

tion is no the equilibrium thermodynamic process.

evaluation in multilayer structures.

influence. Scattering angle is 160. Energy step 1.9 keV/channel.

Figure 19. Experimental and theoretical RBS He+ ions spectra for the Au/Cu bimetallic structure pre and post-treatment of the thermal action. The long time treatment at T = 493 K during 2400 sec of Au (44 nm)/Cu (190 nm) led to bulk interatomic diffusion (a). The short time treatment at T = 523 K during 300 sec showed the grain boundary diffusion, only. Second case is illustrated the table of the depth element distribution. Energy step 3.8 keV/channel.

#### 3.4. Special features of the material density analysis

The material atomic density is a principle parameter of the substance condenses state. This parameter magnitude is usually defined by direct measurement of the subject mass and volume. But this method is not suitable for the material density determination of thin film structures. The Rutherford backscattering method can help to solve this problem. The atomic density distinction must lead to variation of the RBS yield intensity. Figure 20 shows that the

Figure 20. Experimental RBS H+ ions (E0 = 1.557 MeV) spectra for diamond (r = 3.52 g/cm3 ) and glassy carbon (r = 2.21 g/cm3 ) sample. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

expected effect takes place, really. RBS H+ ions spectra for the diamond crystal and for the glass carbon sample are not equivalent. The diamond structure is characterized by a more compact atomic packing and demonstrated the enhanced scattering yield in the RBS spectrum. Its effect can be used for study of the porous structures. Figure 21 shows the sample of the Rutherford backscattering study of the Al film in conditions after its preparation and in the result of thermal treatment [32]. Initial spectrum demonstrates the smaller scattering intensity yield in comparison with the theoretical spectrum (a). It is connected with the structure vacancy concentration near 6%. The thermal treatment let to the Al film, thickness decreasing from 300 to 284 nm (see the diagram (c)). The comparison of initial and finishing experimental spectra demonstrates the thickness decreasing and the atomic density increasing up to the normal structure value. Similar investigations is very important because the thin film preparation is no the equilibrium thermodynamic process.

The material atomic density variation can be connected with not only the structural vacancy appearing. Material in the nanostructure state is characterized by the increase in interatomic distance [33]. Figure 22 demonstrates the Rutherford backscattering yield decreasing for the Ag thin films deposited on the silicon substrate. There are presented two RBS He+ (E0 = 1.27 MeV) ions spectra collected by our double detector system (θ1 = 160, θ2 = 120). Theoretical approximation of these spectra showed that the Ag film thickness is equal 48 nm but the evident discrepancy between Ag theoretical and experimental partial spectra was discovered. In this case, it was nearly equal to 6%. Moreover, the discrepancy increases as the Ag film became more slender and disappears when it will be large 100 nm. Our diffraction measurements confirmed supposition about the atomic density decreasing as aresult of the interatomic distance growth. Similar RBS investigations can be very useful for the material atomic density evaluation in multilayer structures.

3.4. Special features of the material density analysis

Figure 19. Experimental and theoretical RBS He+

52 Ion Beam Applications

The material atomic density is a principle parameter of the substance condenses state. This parameter magnitude is usually defined by direct measurement of the subject mass and volume. But this method is not suitable for the material density determination of thin film structures. The Rutherford backscattering method can help to solve this problem. The atomic density distinction must lead to variation of the RBS yield intensity. Figure 20 shows that the

the thermal action. The long time treatment at T = 493 K during 2400 sec of Au (44 nm)/Cu (190 nm) led to bulk interatomic diffusion (a). The short time treatment at T = 523 K during 300 sec showed the grain boundary diffusion, only.

Second case is illustrated the table of the depth element distribution. Energy step 3.8 keV/channel.

Figure 20. Experimental RBS H+ ions (E0 = 1.557 MeV) spectra for diamond (r = 3.52 g/cm3

) sample. Measurement geometry is shown on insert. Energy step 1.9 keV/channel.

g/cm3

ions spectra for the Au/Cu bimetallic structure pre and post-treatment of

) and glassy carbon (r = 2.21

Figure 21. Experimental and theoretical RBS He+ (E0 = 1.5 MeV) ions for Al/SiO2 structure pre (a) and post-thermal treatment (b) and the experimental diagram of the Al thin film thickness variation in result of the thermal treatment influence. Scattering angle is 160. Energy step 1.9 keV/channel.

ion beam excitation method from X-ray, electron beams and gamma radiation ones is the very high efficiency of the low energy characteristic radiation excitation. In this plane, it is very interesting to compare the X-ray fluorescence yield excitation cross-section at use the X-ray high energy flux (MoKα, E = 17.4 keV) and the proton high energy beam. These data arepresented in Figure 23 [34]. Cross-sections of X-ray low energy lines excitation by the MoKα radiation flux use are characterized by very small magnitudes. At the same time, these parameters in conditions of the proton beam use demonstrate high values, especially for the low energy lines excitation. Comparison of YKα and AlKα fluorescence excitation cross-section in case of the MoKα radiation flux application shows that the yttrium fluorescence excitation efficiency is higher as the aluminum one on three orders. Similar comparison of these elements fluorescence excitation cross-sections at the proton beam excitation with energy E0 = 1 MeV shows that the situation will be changed on the reverse one. So, it is evident that the light element diagnostic difficulties at the X-ray beam fluorescence application can be compensate by use the PIXE method [35, 36]. The Xray fluorescence excitation by ion beams is more effective not only in comparison with the X-ray hard radiation flux application. PIXE bears some similarity to the fluorescence yield electron beam excitation but it characterizes by smaller values of the bremsstrahlung photon intensity yield. As a result, PIXE measurements are distinguished by the background lower level in comparison with the electron excitation. This fact is illustrated in Figure 24 [7]. The spectra

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Figure 24. X-ray fluorescence spectra of the human brain tissue collected in conditions of the electron beam (E0 = 20 keV)

excitation (a) and the proton beam (E0 = 2.5keV)application (b) [36].

Figure 22. Experimental, theoretical and subtraction RBS He+ (E0 = 1.27 MeV) ions spectra for the Ag thin film deposited on Si substrate. Spectra were collected by the double detector system (θ1 =160 and θ2 = 120). Measurement geometries is presented on inserts. Energy step 1.9 keV/channel.

## 4. Particle-induced X-ray emission

#### 4.1. Common principles of the method

Particle-induced X-ray emission is an ion analytical method, which utilizes the X-ray characteristic yield induced by ion beam interacting with the electron subsystem of target atoms. X-ray characteristic energy depends on Z atomic number of the target atom. PIXE method similar to other X-ray fluorescence diagnostic technologies collects the characteristic lines yield corresponding to K, L and M radiation series. At the same time, the main distinguishing of the

Figure 23. Cross-section of the X-ray fluorescence excitation by proton beam [34] (a) and MoKα radiation flux (b).

ion beam excitation method from X-ray, electron beams and gamma radiation ones is the very high efficiency of the low energy characteristic radiation excitation. In this plane, it is very interesting to compare the X-ray fluorescence yield excitation cross-section at use the X-ray high energy flux (MoKα, E = 17.4 keV) and the proton high energy beam. These data arepresented in Figure 23 [34]. Cross-sections of X-ray low energy lines excitation by the MoKα radiation flux use are characterized by very small magnitudes. At the same time, these parameters in conditions of the proton beam use demonstrate high values, especially for the low energy lines excitation. Comparison of YKα and AlKα fluorescence excitation cross-section in case of the MoKα radiation flux application shows that the yttrium fluorescence excitation efficiency is higher as the aluminum one on three orders. Similar comparison of these elements fluorescence excitation cross-sections at the proton beam excitation with energy E0 = 1 MeV shows that the situation will be changed on the reverse one. So, it is evident that the light element diagnostic difficulties at the X-ray beam fluorescence application can be compensate by use the PIXE method [35, 36]. The Xray fluorescence excitation by ion beams is more effective not only in comparison with the X-ray hard radiation flux application. PIXE bears some similarity to the fluorescence yield electron beam excitation but it characterizes by smaller values of the bremsstrahlung photon intensity yield. As a result, PIXE measurements are distinguished by the background lower level in comparison with the electron excitation. This fact is illustrated in Figure 24 [7]. The spectra

4. Particle-induced X-ray emission

Particle-induced X-ray emission is an ion analytical method, which utilizes the X-ray characteristic yield induced by ion beam interacting with the electron subsystem of target atoms. X-ray characteristic energy depends on Z atomic number of the target atom. PIXE method similar to other X-ray fluorescence diagnostic technologies collects the characteristic lines yield corresponding to K, L and M radiation series. At the same time, the main distinguishing of the

Figure 23. Cross-section of the X-ray fluorescence excitation by proton beam [34] (a) and MoKα radiation flux (b).

Figure 22. Experimental, theoretical and subtraction RBS He+ (E0 = 1.27 MeV) ions spectra for the Ag thin film deposited on Si substrate. Spectra were collected by the double detector system (θ1 =160 and θ2 = 120). Measurement geometries is

4.1. Common principles of the method

presented on inserts. Energy step 1.9 keV/channel.

54 Ion Beam Applications

Figure 24. X-ray fluorescence spectra of the human brain tissue collected in conditions of the electron beam (E0 = 20 keV) excitation (a) and the proton beam (E0 = 2.5keV)application (b) [36].

comparison shows that the ion beam excitation leads to the background intensity decreasing in result of the bremsstrahlung photon yield reduction. In the presented data, the ion beam excitation application allows to registrate Fe, Cu and Zn atoms presence in the studied target. In the result, one can establish that the PIXE method is characterized by very low magnitudes of detection levels. At the same time, it should be emphasized that the PIXE spectrometry is not the quantitative analytical method. PIXE measurement results are controlled by the matrix effect [37] and by the specific factor connected with the absorption cross-section distinction for different characteristic lines. The last factor is defined by the material layer thickness responsible for the line X-ray fluorescence yield. (This factor can be eliminatedby usingthe planar X-ray waveguideresonator, see Figure 5.)

PIXE element diagnostics, in addition to the matrix and absorption effects, must take into account specific peculiarities of the X-ray fluorescence yield registration by the energy dispersion detector. Any X-ray detector is equipped by the input window, which absorbs the collected radiation. Moreover, X-ray detector is characterized by the reduced efficiency at the high energy photon registration. Figure 25 presents the experimental diagram reflectingthe X-ray radiation efficiency registration for the wide range of photon energy. Best results of the light element diagnostics can be obtained with X-ray detectors equipped by C1 and C2 superfine windows because it allow to collect PIXE spectra up to the photon energy E ffi 0.1 keV. As a whole, the PIXE spectrometry is very beautiful supplement to the RBS spectrometry.

## 4.2. PIXE for the material element analysis

Distinction in the X-ray fluorescence yield excitation cross-section demonstrated in Figure 23 can be illustrated by the direct experimental measurements. Figure 26 shows spectra of the X-ray fluorescence yield excited by the proton beam and the MoKα radiation flux. For the reference, the figure presents experimental and theoretical RBS spectra of the target. The target is the silicon-germanium epitaxial film with thickness 112 nm on the silicon monocrystal substrate. Experimental spectrum was collected in the target random position. Comparison of X-ray fluorescence spectra collected in conditions of the different excitation methods use shows that the PIXE approach is more effective for the light element diagnostics in materials, but the X-ray fluorescence excitation is more preferable in case of the heavy element analysis. It is very important to notice that the ion beam excitation provokes the X-ray characteristic fluorescence yield by very high intensity. The spectrum excited by the proton beam with current I = 2 nA (1.2 1010 ion/sec) was registeredfor 5 seconds, at the same time, the time registration of spectrum excited by the MoKα radiation flux (N = 4 105 photon/sec) was equal 300 s. High intensity of the X-ray fluorescence yield characteristic for the first spectrum is borne out by the double imposition peak appearance. So, in the last experiments, we use SDD silicon detector in frame of the Sokol-3 ion beam analytical complex facility, which can work at

Figure 26. Comparison of X-ray fluorescence yield for Si0.85Ge0.15/Si epitaxial structure collected in conditions of the proton beam (a) and the MoKα radiation flux excitation (b). Arrows shows the energy position of X-ray characteristic lines collected by X-ray pin detector. Insertions show the measurements geometry and RBS He+ (E0 = 1.525 MeV) ions spectrum

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High efficiency of the PIXE light element diagnostics was used in our investigations of the geological object. Figure 27 shows the proton-induced X-ray emission spectrum of the (Mg0.93Fe0.07)2SiO4 natural olivine. Host composition of the mineral was defined by RBS method. Experimental and theoretical spectra of the object are presented in the figure, too. PIXE measurements allow to fix in the target structure the Ca, Cl, S, Al and Na elements set existence. Quantitative analysis of the target contamination can be carried out by the TXRF

PIXE spectrometry can be used for petroleum contamination analysis. Figure 28 shows TXRF and PIXE spectra demonstrating the contamination set existence in the petroleum film deposited on Be substrate. RBS spectrum of the film is shown in Figure 14. TXRF spectrum allows to

the enhanced pulse loading without double imposition peaks.

for the target. Energy steps for ones 1.9 keV/channel.

spectrometric method [38].

Figure 25. X-ray radiation energy efficiency of the SDD detector equippedby different input windows. Insert shows the efficiency dependence on the detector working plate thickness.

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comparison shows that the ion beam excitation leads to the background intensity decreasing in result of the bremsstrahlung photon yield reduction. In the presented data, the ion beam excitation application allows to registrate Fe, Cu and Zn atoms presence in the studied target. In the result, one can establish that the PIXE method is characterized by very low magnitudes of detection levels. At the same time, it should be emphasized that the PIXE spectrometry is not the quantitative analytical method. PIXE measurement results are controlled by the matrix effect [37] and by the specific factor connected with the absorption cross-section distinction for different characteristic lines. The last factor is defined by the material layer thickness responsible for the line X-ray fluorescence yield. (This factor can be eliminatedby usingthe planar X-ray waveguide-

PIXE element diagnostics, in addition to the matrix and absorption effects, must take into account specific peculiarities of the X-ray fluorescence yield registration by the energy dispersion detector. Any X-ray detector is equipped by the input window, which absorbs the collected radiation. Moreover, X-ray detector is characterized by the reduced efficiency at the high energy photon registration. Figure 25 presents the experimental diagram reflectingthe X-ray radiation efficiency registration for the wide range of photon energy. Best results of the light element diagnostics can be obtained with X-ray detectors equipped by C1 and C2 superfine windows because it allow to collect PIXE spectra up to the photon energy E ffi 0.1 keV. As a

whole, the PIXE spectrometry is very beautiful supplement to the RBS spectrometry.

Distinction in the X-ray fluorescence yield excitation cross-section demonstrated in Figure 23 can be illustrated by the direct experimental measurements. Figure 26 shows spectra of the

Figure 25. X-ray radiation energy efficiency of the SDD detector equippedby different input windows. Insert shows the

resonator, see Figure 5.)

56 Ion Beam Applications

4.2. PIXE for the material element analysis

efficiency dependence on the detector working plate thickness.

Figure 26. Comparison of X-ray fluorescence yield for Si0.85Ge0.15/Si epitaxial structure collected in conditions of the proton beam (a) and the MoKα radiation flux excitation (b). Arrows shows the energy position of X-ray characteristic lines collected by X-ray pin detector. Insertions show the measurements geometry and RBS He+ (E0 = 1.525 MeV) ions spectrum for the target. Energy steps for ones 1.9 keV/channel.

X-ray fluorescence yield excited by the proton beam and the MoKα radiation flux. For the reference, the figure presents experimental and theoretical RBS spectra of the target. The target is the silicon-germanium epitaxial film with thickness 112 nm on the silicon monocrystal substrate. Experimental spectrum was collected in the target random position. Comparison of X-ray fluorescence spectra collected in conditions of the different excitation methods use shows that the PIXE approach is more effective for the light element diagnostics in materials, but the X-ray fluorescence excitation is more preferable in case of the heavy element analysis. It is very important to notice that the ion beam excitation provokes the X-ray characteristic fluorescence yield by very high intensity. The spectrum excited by the proton beam with current I = 2 nA (1.2 1010 ion/sec) was registeredfor 5 seconds, at the same time, the time registration of spectrum excited by the MoKα radiation flux (N = 4 105 photon/sec) was equal 300 s. High intensity of the X-ray fluorescence yield characteristic for the first spectrum is borne out by the double imposition peak appearance. So, in the last experiments, we use SDD silicon detector in frame of the Sokol-3 ion beam analytical complex facility, which can work at the enhanced pulse loading without double imposition peaks.

High efficiency of the PIXE light element diagnostics was used in our investigations of the geological object. Figure 27 shows the proton-induced X-ray emission spectrum of the (Mg0.93Fe0.07)2SiO4 natural olivine. Host composition of the mineral was defined by RBS method. Experimental and theoretical spectra of the object are presented in the figure, too. PIXE measurements allow to fix in the target structure the Ca, Cl, S, Al and Na elements set existence. Quantitative analysis of the target contamination can be carried out by the TXRF spectrometric method [38].

PIXE spectrometry can be used for petroleum contamination analysis. Figure 28 shows TXRF and PIXE spectra demonstrating the contamination set existence in the petroleum film deposited on Be substrate. RBS spectrum of the film is shown in Figure 14. TXRF spectrum allows to

Figure 27. PIXE spectrum of the olivine natural crystal collected in result of H+ ion beam excitation. Arrows shows the energy position of X-ray characteristical lines collected by SDD silicon detector. Rutherford backscattering spectrum of the target is presented on insert. Energy step for PIXE spectrum 10.9 eV/channel, for RBS 1.9 keV/channel.

Figure 28. X-ray fluorescence spectra collected for the petroleum film deposited on Be substrate by use the TXRF and the PIXE spectrometry. Energy step for TXRF spectrum 20 eV/channel, and 10 eV/channel for PIXE spectrum. TXRF fluorescence yield was excited by the MoKα flux, PIXE – by the proton beam with energy E0 = 0.953 MeV. Arrows show the

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Figure 29. Experimental and theoretical RBS H+ (E0 = 1.3 MeV) ions for the sample of thin leather – processing material and PIXE spectrum of the one collected in the same experiment. Arrows on the RBS spectrum show the ion scattering energies on nuclei of atoms located on the sample surface, and on the PIXE spectrum show the energy position of X-ray characteristical lines collected by SDD silicon detector. Energy step for RBS spectrum 1.9 keV/channel, for PIXE one 10 eV/

energy position of X-ray characteristic lines collected by SDD silicon detector.

channel. Insert shows the measurement geometry.

produce the quantitative analysis of the contamination concentration that used the sulfur atomic content as the internal standard. TXRF and PIXE spectra confirm the vanadium atoms presence in the petroleum sample. At the same time, the La atoms concentration diagnostics is inaccessible for the total X-ray external fluorescence spectrometry. PIXE analysis is able to fix the La atoms presence in the petroleum sample. The lanthanum atomic content was evaluated by usingthe comparison method with data for Ca and V atom concentration. It is 0.0005 if the sulfur concentration is elected as a one. PIXE diagnostics of the solution dry residue is the very perspective application for this specific target.

PIXE measurements can be used for the nonstandard element analysis. Figure 29 shows RBS and PIXE spectra collected for the leather processing material by usingthe proton beam excitation. RBS spectrum allows to evaluate the host elements concentration (except hydrogen atom), at the same time, the PIXE investigation takes possibilities to fix the contamination element presence in the leather processing material. How showed experience of the leather goods manufacturing the chromium and contamination concentrations defines quality of different products manufactured from the leather. The quantitative contamination analysis can be executed by TXRF method application. But if the TXRF spectrometry sensitivity is not enough, it is possible to use the planar X-ray waveguide-resonator for the trace surface element diagnostics in frame of the PIXE excitation of the X-ray fluorescence yield. The experimental scheme for such measurement execution is presented in Figure 5b, and the diagnostic method has name – TXRF PE.

Figure 30 presents the experimental data characterizing the method possibilities on base of the old coin study. PIXE spectrum shows X-ray fluorescence lines initiated by surface and

Ion Beams for Materials Analysis: Conventional and Advanced Approaches http://dx.doi.org/10.5772/intechopen.76297 59

Figure 28. X-ray fluorescence spectra collected for the petroleum film deposited on Be substrate by use the TXRF and the PIXE spectrometry. Energy step for TXRF spectrum 20 eV/channel, and 10 eV/channel for PIXE spectrum. TXRF fluorescence yield was excited by the MoKα flux, PIXE – by the proton beam with energy E0 = 0.953 MeV. Arrows show the energy position of X-ray characteristic lines collected by SDD silicon detector.

produce the quantitative analysis of the contamination concentration that used the sulfur atomic content as the internal standard. TXRF and PIXE spectra confirm the vanadium atoms presence in the petroleum sample. At the same time, the La atoms concentration diagnostics is inaccessible for the total X-ray external fluorescence spectrometry. PIXE analysis is able to fix the La atoms presence in the petroleum sample. The lanthanum atomic content was evaluated by usingthe comparison method with data for Ca and V atom concentration. It is 0.0005 if the sulfur concentration is elected as a one. PIXE diagnostics of the solution dry residue is the very

Figure 27. PIXE spectrum of the olivine natural crystal collected in result of H+ ion beam excitation. Arrows shows the energy position of X-ray characteristical lines collected by SDD silicon detector. Rutherford backscattering spectrum of the

target is presented on insert. Energy step for PIXE spectrum 10.9 eV/channel, for RBS 1.9 keV/channel.

PIXE measurements can be used for the nonstandard element analysis. Figure 29 shows RBS and PIXE spectra collected for the leather processing material by usingthe proton beam excitation. RBS spectrum allows to evaluate the host elements concentration (except hydrogen atom), at the same time, the PIXE investigation takes possibilities to fix the contamination element presence in the leather processing material. How showed experience of the leather goods manufacturing the chromium and contamination concentrations defines quality of different products manufactured from the leather. The quantitative contamination analysis can be executed by TXRF method application. But if the TXRF spectrometry sensitivity is not enough, it is possible to use the planar X-ray waveguide-resonator for the trace surface element diagnostics in frame of the PIXE excitation of the X-ray fluorescence yield. The experimental scheme for such measurement execution is presented in Figure 5b, and the diagnostic method

Figure 30 presents the experimental data characterizing the method possibilities on base of the old coin study. PIXE spectrum shows X-ray fluorescence lines initiated by surface and

perspective application for this specific target.

has name – TXRF PE.

58 Ion Beam Applications

Figure 29. Experimental and theoretical RBS H+ (E0 = 1.3 MeV) ions for the sample of thin leather – processing material and PIXE spectrum of the one collected in the same experiment. Arrows on the RBS spectrum show the ion scattering energies on nuclei of atoms located on the sample surface, and on the PIXE spectrum show the energy position of X-ray characteristical lines collected by SDD silicon detector. Energy step for RBS spectrum 1.9 keV/channel, for PIXE one 10 eV/ channel. Insert shows the measurement geometry.

Figure 30. TXRF PE (a) and PIXE (b) spectra of the half copeek old coin fabricated from copper with the surface Ag coating (t= 170 nm) collected by SDD silicon detector in conditions of the X-ray fluorescence excitation by the proton beam (E0 = 1.25 MeV). Inserts show measurements geometry and RBS H+ ions spectrum of the target. Arrows on fluorescence spectra show of the energy position of X-ray characteristical lines and on RBS one ion scattering energies on nuclei located on the coin surface. Energy step for fluorescence spectra 10.5 eV/channel for RBS one 1.9 keV/channel.

volume atoms of the target. In its turn, TXRF PE spectrum reflects X-ray fluorescence lines characteristic for the coin surface. (Carbon peak on the Rutherford backscattering diagram is connected with the C-H film appearing in process of the proton beam scattering in the measurement period.) The X-ray fluorescence spectra comparison allows to conclude that the Mg, Al and Fe atoms contamination are typical for the Ag coating. This conclusion was confirmed by the TXRF direct study. So, new experimental method can be recommended for the trace light elements diagnostic in addition to the standard TXRF experimental measurements.

The nuclei recoil spectrometry, similar to the RBS method allows to produce the absolute analysis. At the same time, it is possible to use standard samples attested by the precision weighting. We used TiH0.98 as the similar etalon. Figure 31 shows NER spectra of the etalon and some perovskite structures. Data obtained from the etalon spectrum allows to evaluate the hydrogen content in studied perovskite structures. It is very strange but the hydrogen atoms concentration in the SrTiO3 monocrystalline structure was near 4% at. Similar hydrogen content was detected in the BSTO film deposited on MgO substrate. The BSTO film deposited on the silicon substrate had smaller hydrogen atoms in its structure (near 1% at.). Evaluation of the hydrogen atoms in surface absorbed layers shows that the film has the C1H1 composition. NER measurements are characterized by specific conditions. The helium ion beam energy must be higher as 1.5 MeV. At smaller energy of the beam some experimental and interpreting

Figure 31. Nuclei elastic recoil spectra of the TiH0.98 weighting etalon (a) and some perovskite structures (b) collected in the specific geometry allowed to fix the hydrogen atoms recoil. Hydrogen recoil spectrum for SrTiO3monocrystal (●), for BSTO film on MgO substrate (▲), for BSTO film Si substrate (♦). Measurement geometry is presented on insert. Energy

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6. Nuclear reaction analysis application for the material study

nuclear reactions have the practical significance. It is the 27Al(p,γ)

Nuclear reactions excited by high energy ion beams can have the resonance nature and can demonstrate the threshold characteristics[39]. It is the isotopically sensitive methods. Some

reaction, which uses for the ion beam accelerator calibration [40]. Nuclear reaction analysis (NRA) is mostly used for the light element diagnostics in material. In our work we applied the

The main investigation task of the study was the elements spatial distribution determination in the engine output jet. The engine discharge chamber was manufactured from the material elaborated on the BN base composition. So, it is expected that the main admixture element in the xenon jet will be boron. For the boron spatial distribution in the engine jet, we used the Be plates set arranged on different angles about the jet propagation line. The deposit on the Be

Be nuclear reaction for study of the electro-rocket engine function peculiarities [41].

28Si famous resonance

difficulties appear.

step 3.8 keV/channel.

11B(p,α) 8

## 5. Nuclear elastic recoil for the hydrogen diagnostics

It is known, that the hydrogen atoms diagnostic can be carried out by using the direct resonance nuclear reaction, for example,1 H(15N; α,γ) 12C and 1 H(19F; α,γ) 16O, or by the nuclear elastic recoil (NER) method [16]. The resonance method has a limited spearing because its application demands ion beams with the enhanced energy. For example, the low energy resonance of 1 H(15N; α,γ) 12C reaction has value 3.35 MeV. So, the nuclear recoil spectrometry is more accessible while less informative. The experimental scheme for the nuclear recoil method is presented in Figure 6b. The measurement scheme assumes the surface target installation on the θ1/2 small angle about of the helium ion beam propagation line and the recoil and scattering ion detector placing under the θ1 angle. The detector must have a collimator and the thin film absorber. The absorber thickness must provide a total absorption of the helium ions scattering flux. In these conditions, the recoil hydrogen atoms undergo the noticeable straggling [10–16]. The straggling effect is characterized by the ion beam average energy decreasing attended by increasing of the ΔE energy dispersion. Moreover, it is a need to take into account the adsorbed layer existence on the any material surface, which contains some hydrogen quantity. As a rule, the hydrogen surface concentration is higher in comparison of the hydrogen target volume content.

Ion Beams for Materials Analysis: Conventional and Advanced Approaches http://dx.doi.org/10.5772/intechopen.76297 61

Figure 31. Nuclei elastic recoil spectra of the TiH0.98 weighting etalon (a) and some perovskite structures (b) collected in the specific geometry allowed to fix the hydrogen atoms recoil. Hydrogen recoil spectrum for SrTiO3monocrystal (●), for BSTO film on MgO substrate (▲), for BSTO film Si substrate (♦). Measurement geometry is presented on insert. Energy step 3.8 keV/channel.

The nuclei recoil spectrometry, similar to the RBS method allows to produce the absolute analysis. At the same time, it is possible to use standard samples attested by the precision weighting. We used TiH0.98 as the similar etalon. Figure 31 shows NER spectra of the etalon and some perovskite structures. Data obtained from the etalon spectrum allows to evaluate the hydrogen content in studied perovskite structures. It is very strange but the hydrogen atoms concentration in the SrTiO3 monocrystalline structure was near 4% at. Similar hydrogen content was detected in the BSTO film deposited on MgO substrate. The BSTO film deposited on the silicon substrate had smaller hydrogen atoms in its structure (near 1% at.). Evaluation of the hydrogen atoms in surface absorbed layers shows that the film has the C1H1 composition. NER measurements are characterized by specific conditions. The helium ion beam energy must be higher as 1.5 MeV. At smaller energy of the beam some experimental and interpreting difficulties appear.

## 6. Nuclear reaction analysis application for the material study

volume atoms of the target. In its turn, TXRF PE spectrum reflects X-ray fluorescence lines characteristic for the coin surface. (Carbon peak on the Rutherford backscattering diagram is connected with the C-H film appearing in process of the proton beam scattering in the measurement period.) The X-ray fluorescence spectra comparison allows to conclude that the Mg, Al and Fe atoms contamination are typical for the Ag coating. This conclusion was confirmed by the TXRF direct study. So, new experimental method can be recommended for the trace light elements diagnostic in addition to the standard TXRF experimental

on the coin surface. Energy step for fluorescence spectra 10.5 eV/channel for RBS one 1.9 keV/channel.

Figure 30. TXRF PE (a) and PIXE (b) spectra of the half copeek old coin fabricated from copper with the surface Ag coating (t= 170 nm) collected by SDD silicon detector in conditions of the X-ray fluorescence excitation by the proton beam (E0 = 1.25 MeV). Inserts show measurements geometry and RBS H+ ions spectrum of the target. Arrows on fluorescence spectra show of the energy position of X-ray characteristical lines and on RBS one ion scattering energies on nuclei located

It is known, that the hydrogen atoms diagnostic can be carried out by using the direct reso-

elastic recoil (NER) method [16]. The resonance method has a limited spearing because its application demands ion beams with the enhanced energy. For example, the low energy

is more accessible while less informative. The experimental scheme for the nuclear recoil method is presented in Figure 6b. The measurement scheme assumes the surface target installation on the θ1/2 small angle about of the helium ion beam propagation line and the recoil and scattering ion detector placing under the θ1 angle. The detector must have a collimator and the thin film absorber. The absorber thickness must provide a total absorption of the helium ions scattering flux. In these conditions, the recoil hydrogen atoms undergo the noticeable straggling [10–16]. The straggling effect is characterized by the ion beam average energy decreasing attended by increasing of the ΔE energy dispersion. Moreover, it is a need to take into account the adsorbed layer existence on the any material surface, which contains some hydrogen quantity. As a rule, the hydrogen surface concentration is higher in comparison of the hydro-

12C and 1

12C reaction has value 3.35 MeV. So, the nuclear recoil spectrometry

H(19F; α,γ)

16O, or by the nuclear

H(15N; α,γ)

5. Nuclear elastic recoil for the hydrogen diagnostics

measurements.

60 Ion Beam Applications

resonance of 1

gen target volume content.

nance nuclear reaction, for example,1

H(15N; α,γ)