RATIONAL-FUNCTION APPROXIMATION OF NUCLEAR-SCATTERING CROSS-SECTION FUNCTION

The one-variable scattering cross-section function f(eta) proposed by Lindhard, Nielsen and Scharff (LNS) is approximated by a rational func tion using the minimax algorithm in this work. Taking an ingenious tra nsformation ion of the variable eta, this approximation is about one o rder of magnitude faster than other approximations in the literature. To maintain a reasonable accuracy, we divide the wide variable range i nto two regions. In addition, an adaptive integration method is adopte d to compute the scattering angle and the nuclear stopping power in or der to get accurate f(eta) data.