X-ray crystallography elastic X-ray scattering include powder diffraction, Small-Angle X-ray Scattering (SAXS) and several types of X-ray fiber diffraction, which was used by Rosalind Franklin in determining the double-helix structure of DNA. In general, single-crystal X-ray diffraction offers more structural information than these other techniques; however, it requires a sufficiently large and regular crystal, which is not always available. These scattering methods generally use "monochromatic" X-rays, which are restricted to a single wavelength with minor deviations. A broad spectrum of X-rays (that is, a blend of X-rays with different wavelengths) can also be used to carry out X-ray diffraction, a technique known
Rosalind Franklin and DNA was a general consensus at the time that they were at the inside); and the other is that DNA exists in two forms, a crystalline (dry form) A-DNA and a hydrated (wet form) B-DNA. With her PhD student Raymond Gosling, she produced a series of X-ray images of DNA. The photograph (number 51, hence, popularised as Photo 51) of B-DNA taken in May 1952 was especially crucial. X-ray crystallography did not immediately show the precise helical structure. Franklin chose to work on A-DNA, while B-DNA was given to Maurice Wilkins. By the early 1953, Franklin was aware that both A