Semi empirical formula to calculate MSP of relativistic electrons in the range of 940 keV–1020 keV

A semi empirical formula has been obtained to calculate the Mass stopping power (MSP) of relativistic electrons in the energy range of 950 keV–1050 keV, for any material of atomic number or Zeff ranging from 10–82. The MSP of 942 keV and 1016 keV internal conversion electrons of Bi207 are obtained by allowing them to pass through the targets of atomic numbers 13, 29, 47, 50, 79 and 82. The energies of the incident and transmitted electrons are measured using a Si(Li) detector coupled to 8 K multi channel analyzer and the MSP has been determined from the measured incident and transmitted energies. The resultant variation of MSP with the atomic number of the material is plotted and best fitted to a first order exponential equation. The results predicted by this semi empirical formula are compared with the NIST-ESTAR database & Batra's formula and found to be in good agreement. Application of this formula to calculate the MSP and effective atomic number of any biological sample or compound is discussed.