Stopping powers of A-150 tissue equivalent plastic for protons from 2.5 TO 7.5 MeV

Abstract

The stopping powers of A-150 tissue equivalent plastic for protons having energies from 2.5 to 7.5 MeV have been measured with an uncertainty of ± 0.35%. The experimental results have been compared with the calculated stopping powers obtained by Bragg's additivity rule using the stopping power values for constituent elements calculated by Andersen and Ziegler's formula. The calculated values agree with the experimental data to within 0.5%. The Ivalue has been extracted by comparing the calculated values with the experimental data taking the Ivalue as an adjustable parameter. Using Andersen and Ziegler's shell correction, the I value has been determined as 62.5 eV. Using the Bonderup shell correction, the Barkas correction and the Bloch correction, the I value has been determined as 64.7 eV. It is considered that these two I values agree with each other and with the value 65.1 eV recommended in ICRU Report 37 within the uncertainties of the theories.