GEANT321/gphys/gphak.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:21:29  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.22  by  S.Giani
  11 *-- Author :
  12       REAL FUNCTION GPHAK(BET)
  13 C.
  14 C.    ******************************************************************
  15 C.    *                                                                *
  16 C.    *  Generates Photoelectron Angular ditribution from K shell      *
  17 C.    *   from L1 shell ditribution ENTRY GPHAL1                       *
  18 C.    *                                                                *
  19 C.    *    ==>CALLED BY : GPHOT                                        *
  20 C.    *       AUTHOR    : J. Chwastowski                               *
  21 C.    *                                                                *
  22 C.    ******************************************************************
  23 C.
  24       DOUBLE PRECISION SAUT1,SAUT2,SAUT3,DRN
  25       DOUBLE PRECISION COST,SIN2T,X,ANOR,AMAJOR
  26       DOUBLE PRECISION GAMA,G1,G2,BETA,B1,ONE,HALF
  27       PARAMETER (BETMAX=0.999999)
  28       PARAMETER (ONE=1,HALF=ONE/2)
  29       DIMENSION RAN(2),BETVAL(7),AMAJOR(7)
  30       DATA BETVAL / 0.8601,0.901,0.9901,0.99901,0.999901,0.9999901,
  31      +              0.99999901 /
  32       DATA AMAJOR / 1.02,1.1,4.3,19.,68.,221.,704. /
  33       DATA ANOR / 0.0 /
  34 C
  35 C L1 shell entry
  36 C
  37       ENTRY GPHAL1(BET)
  38 C
  39       BETA = MIN(BET,BETMAX)
  40       B1 = ONE-BETA
  41       G2 = ONE/((ONE-BETA)*(ONE+BETA))
  42       GAMA = SQRT(G2)
  43       G1 = GAMA-ONE
  44       DO 10 I = 1,7
  45        IF(BETA.LE.BETVAL(I)) THEN
  46         ANOR = AMAJOR(I)*G2
  47         ANOR = ONE/ANOR
  48         GO TO 20
  49        ENDIF
  50    10 CONTINUE
  51    20 SAUT2 = HALF*GAMA*G1*(GAMA-2)
  52       GPHAK = 0.0
  53    30 CONTINUE
  54       CALL GRNDM(RAN,2)
  55       DRN = 2*RAN(1)
  56       SAUT1 = (DRN-B1)/(DRN*BETA+B1)
  57       COST = SAUT1
  58       X = ONE-BETA*COST
  59       SIN2T = (ONE-COST)*(ONE+COST)
  60       SAUT3 = SIN2T/(X**2)*(ONE+SAUT2*X)*ANOR
  61       IF(RAN(2).GT.SAUT3) GO TO 30
  62       GPHAK = COST
  63       GPHAL1 = GPHAK
  64       END