BACKSCATTERING OF BETA-PARTICLES FROM THICK TARGETS

The backscattering coefficients η for electron and positron spectra emitted by radioactive sources, with the maximum energy of beta-particles from 309-1894 keV, are found using the transport problem and solved numerically with the use of the segment model. The backscattering coefficient into 2 π is shown to depend slightly on the maximum energy of the particles spectrum. The η(Z) dependence can be approximated by the linear function of lgZ. The backscattering coefficient for positrons (22Na source) was also examined experimentally in the case of monodirected and isotropic particle incidence on the Al, Ni, Cu, Nb, Mo, W and Pb thick absorbers. A satisfactory agreement of theoretical and experimental data is achieved. © 1979.