5 * Revision 1.1.1.1 1995/10/24 10:21:22 cernlib
9 #include "geant321/pilot.h"
10 *CMZ : 3.21/02 29/03/94 15.41.21 by S.Giani
12 REAL FUNCTION GBTETH(ENER,PARTM,EFRAC)
14 C. ******************************************************************
16 C. * Universal distribution function for the Bremsstrahlung *
17 C. * and pair production angles. This function approximates *
18 C. * the real distribution function which can be found in *
19 C. * Yung-Su Tsai: Rev. Mod. Phys. 46,815(1974) *
20 C. * +erratum : Rev. Mod. Phys. 49,421(1977) *
22 C. * Called by : GBREME, GBREMM, GPAIRG *
23 C. * Authors : L.Urban *
25 C. ******************************************************************
27 #include "geant321/gconsp.inc"
28 #include "geant321/gcmate.inc"
30 PARAMETER (ALFA=0.625)
31 * ----------------------------------------------------------
35 * Angular distribution with d=const
37 * Angular distribution with d=d(Z,E,y)
38 D=0.13*(0.8+1.3/Z)*(100.+1./ENER)*(1.+EFRAC)
39 * -------------------------------------------------------------
46 IF(RNDM(1).LE.W1) THEN
52 U=-(LOG(RNDM(2)*RNDM(3)))/BETA
54 * cut : theta should be .LE. PI !!
55 * this condition depend on E in the case of d=const too!!!!!