National Physical Laboratory of India is realized by using an absolute radiometer. For practical work, a group of tungsten incandescent lamps are used. The level of uncertainty is ± 1.3 × 10. Experimental work has been initiated to realize mole, the SI unit for amount of substance The NPL does not maintain standards of measurements for ionizing radiations. This is the responsibility of the Homi Bhabha Atomic Research Centre, Mumbai. The standards maintained at NPL are periodically compared with standards maintained at other National Metrological Institutes in the world as well as the BIPM in Paris. This exercise ensures that Indian national standards are equivalent
Kerma (physics) rate is converted to tissue equivalent dose using a factor of Sv/Gy (air) = 1.21 for Cs 137 at 0.662 MeV. Kerma (physics) Kerma is an acronym for "kinetic energy released per unit mass", defined as the sum of the initial kinetic energies of all the charged particles liberated by uncharged ionizing radiation (i.e., indirectly ionizing radiation such as photons and neutrons) in a sample of matter, divided by the mass of the sample. It is defined by the quotient formula_1. The SI unit of kerma is the gray (Gy) (or joule per kilogram), the same as the unit of