GEANT321/gphys/gdrele.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:21:24  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.21  by  S.Giani
  11 *-- Author :
  12       SUBROUTINE GDRELE(EEL,CHARGE,JMA,DEDX)
  13 C.
  14 C.    ******************************************************************
  15 C.    *                                                                *
  16 C.    *       Compute ion losses for electron/positron                 *
  17 C.    *                                                                *
  18 C.    *    ==>Called by : GDRELA                                       *
  19 C.    *       Author    G.Patrick *********                            *
  20 C.    *                                                                *
  21 C.    ******************************************************************
  22 C.
  23 #include "geant321/gcbank.inc"
  24 #include "geant321/gconsp.inc"
  25 #include "geant321/gccuts.inc"
  26 C
  27       DATA CONS/0.153536E-3/
  28 C.
  29 C.    ------------------------------------------------------------------
  30 C.
  31       JPROB=LQ(JMA-4)
  32 C
  33       GAM=EEL/EMASS + 1.
  34       GAM2=GAM*GAM
  35       T=GAM-1.
  36       DEDX=0.
  37       IF(T.LE.0.)GO TO 99
  38       TCME=DCUTE/EMASS
  39       BET2=1.-1./GAM2
  40 C     ------------------------------
  41       IF(CHARGE.GT.0.) THEN
  42          Y=1./(1.+GAM)
  43          D=TCME
  44          IF(T.LT.TCME) D=T
  45          D2=D*D/2.
  46          D3=2.*D2*D/3.
  47          D4=D2*D2
  48          F=LOG(T*D)-BET2*(T+2.*D-Y*(3.*D2
  49      *    +Y*(D-D3+Y*(D2-T*D3+D4))))/T
  50 C
  51       ELSE
  52         D=TCME
  53          IF(T.LT.2.*TCME) D=0.5*T
  54          F=-1.-BET2+LOG((T-D)*D)+T/(T-D)
  55      *    +(0.5*D*D+(1.+2.*T)*LOG(1.-D/T))/GAM2
  56       ENDIF
  57 C
  58       POTL=Q(JPROB+11)
  59       FAC=Q(JPROB+12)
  60       C=Q(JPROB+13)
  61       X0=Q(JPROB+14)
  62       X1=Q(JPROB+15)
  63       AA=Q(JPROB+16)
  64 C
  65       X=LOG(GAM2-1.)/4.606
  66       DEL=0.
  67       IF(X.GT.X0)THEN
  68          DEL=4.606*X+C
  69          IF(X.LE.X1)DEL=DEL+AA*(X1-X)**3.
  70       ENDIF
  71 C
  72       DEDX=CONS*FAC*(LOG(2.*T+4.)-2.*POTL+F-DEL)/BET2
  73       IF(DEDX.LT.0.)DEDX=0.
  74 C
  75   99  RETURN
  76       END