GEANT321/gphys/gphal2.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       FUNCTION GPHAL2(BET)
  13 C.
  14 C.    ******************************************************************
  15 C.    *                                                                *
  16 C.    *  Generates Photoelectron Angular ditribution from L2 shell     *
  17 C.    *                                                                *
  18 C.    *    ==>CALLED BY : GPHOT                                        *
  19 C.    *       AUTHOR    : J. Chwastowski                               *
  20 C.    *                                                                *
  21 C.    ******************************************************************
  22 C.
  23       DOUBLE PRECISION SAUT1,SAUT2,SAUT3,SAUT4,SAUT5,SAUT6,SAUT7
  24       DOUBLE PRECISION S1,S2,S3,S4,S5,S6,S7,ONE,HALF
  25       DOUBLE PRECISION COST,SIN2T,X,XI,XI2,XI3,ANOR,DRN
  26       DOUBLE PRECISION GAMA,G1,G2,G3,G4,G5,BETA,B1
  27       DOUBLE PRECISION BETVAL,AMAJOR
  28       PARAMETER(BETMAX=0.999999)
  29       PARAMETER (ONE=1,HALF=ONE/2)
  30       DIMENSION BETVAL(15),AMAJOR(15),RAN(2)
  31       DATA BETVAL / 0.0101,0.101,0.2,0.301,0.401,0.501
  32      +             ,0.601,0.701,0.801,0.901,0.9901,0.99901
  33      +             ,0.999901,0.9999901,0.99999901 /
  34       DATA AMAJOR / 2.05,2.2,2.4,2.6,2.72,3.0,3.2,3.6
  35      +             ,4.4,6.2,25.,88.,280.,900.,2880. /
  36       DATA ANOR / 0.0 /
  37       BETA = MIN(BET,BETMAX)
  38       B1 = ONE-BETA
  39       G2 = ONE/((ONE-BETA)*(ONE+BETA))
  40       GAMA = SQRT(G2)
  41       G3 = G2*GAMA
  42       G4 = G2**2
  43       G5 = G4*GAMA
  44       G1 = GAMA-ONE
  45       DO 10 I = 1,15
  46        IF(BETA.LE.BETVAL(I)) THEN
  47         ANOR = AMAJOR(I)*G5
  48         GO TO 20
  49        ENDIF
  50    10 CONTINUE
  51    20 CONTINUE
  52       ANOR = ONE/ANOR
  53       S1 = HALF*GAMA*(3*GAMA+1)
  54       S2 = -0.125D0*G2*(9*G2+30*GAMA-7)
  55       S3 = 0.25D0*G3*(G3+6*G2+11*GAMA-2)
  56       S4 = -.125D0*G4*G1*(GAMA+7)
  57       S5 = 2*(GAMA+ONE)
  58       S6 = 2*GAMA*(GAMA+ONE)
  59       S7 = 0.125D0*G4*BETA**2*(3*GAMA+ONE)
  60       GPHAL2 = 0.0
  61    30 CONTINUE
  62       CALL GRNDM(RAN,2)
  63       DRN = 2*RAN(1)
  64       COST = (DRN-B1)/(DRN*BETA+B1)
  65       X = ONE-BETA*COST
  66       XI  = ONE/X
  67       XI2 = XI**2
  68       XI3 = XI**3
  69       SIN2T = (ONE-COST)*(ONE+COST)
  70       SAUT1 = S1*XI2
  71       SAUT2 = S2*XI
  72       SAUT3 = S3
  73       SAUT4 = S4*X
  74       SAUT5 = S5*XI3-S6*XI2-S7*XI
  75       SAUT6 = SAUT5*SIN2T
  76       SAUT7 = (SAUT1+SAUT2+SAUT3+SAUT4+SAUT6)*ANOR
  77       IF(RAN(2).GT.SAUT7) GO TO 30
  78       GPHAL2 = COST
  79       END