PARAMETRIZATION OF THE TOTAL PHOTON MASS ATTENUATION COEFFICIENTS IN THE ENERGY-RANGE 0.1-1000 KEV

It is convenient to generate mass attenuation coefficients using semi- empirical schemes. The validity of most of the existing schemes is lim ited to a relatively narrow energy interval (1-40 keV) and their accur acies are poor in some energy regions. In this work, a semi-empirical scheme flexible enough to give a good fit to data in a very wide photo n energy range (0.1-1000 keV) was employed. Fitting coefficients for t he entire range were obtained by utilizing mass attenuation data from two sources: (1) semi-empirical data of Henke et al. in the low photon energy region, and (2) theoretical values generated with the XCOM cod e for fitting in the high energy region. The root mean square of the f it is generally less than 0.2% except for energies below 1 keV where t he available data are scattered. A computer code for generating mass a ttenuation coefficients based on the proposed scheme has been develope d.