GEANT321/gphys/gprsgm.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:21:33  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.23  by  S.Giani
  11 *-- Author :
  12       FUNCTION GPRSGM(Z,T,CCUT)
  13 C.
  14 C.    ******************************************************************
  15 C.    *                                                                *
  16 C.    *       To calculate cross-section in barn/atom for direct       *
  17 C.    *       pair production by muons.                                *
  18 C.    *                                                                *
  19 C.    *    ==>Called by : GPRSGA                                       *
  20 C.    *       Author    L.Urban  *********                             *
  21 C.    *                                                                *
  22 C.    ******************************************************************
  23 C.
  24 #include "geant321/gconsp.inc"
  25 C
  26       PARAMETER (AKSI=1.16,ALFA=3.46,GAM=0.06,VS=0.019)
  27       PARAMETER (ECMIN=2.044E-3,CONMX=0.130653)
  28 C        CONMX=0.75*SQRT(2.7182...)*EMMU
  29 C
  30       DIMENSION C(100),C1(60),C2(40)
  31       EQUIVALENCE (C(1),C1(1)),(C(61),C2(1))
  32       DATA C1/0.230181E-08,-0.280842E-08, 0.137525E-08,-0.156503E-09
  33      +      , 0.728088E-11,-0.122631E-12, 0.133014E-08,-0.160591E-09
  34      +      ,-0.390814E-09, 0.314492E-10, 0.251296E-12,-0.574223E-13
  35      +      , 0.604923E-09,-0.560766E-09, 0.660253E-09,-0.103474E-09
  36      +      , 0.621338E-11,-0.135273E-12, 0.103739E-09, 0.710290E-09
  37      +      ,-0.544755E-10,-0.211241E-11, 0.286443E-12,-0.644602E-14
  38      +      , 0.332492E-09,-0.484785E-10, 0.126921E-10,-0.165217E-11
  39      +      , 0.845273E-13,-0.143180E-14,-0.112267E-13, 0.113308E-11
  40      +      , 0.292577E-12,-0.733441E-13, 0.475747E-14,-0.976279E-16
  41      +      ,-0.112856E-07, 0.936398E-08,-0.291882E-08, 0.422266E-09
  42      +      ,-0.279042E-10, 0.678485E-12, 0.112383E-07,-0.964400E-08
  43      +      , 0.313121E-08,-0.440224E-09, 0.278668E-10,-0.643012E-12
  44      +      ,-0.414131E-08, 0.355112E-08,-0.115035E-08, 0.158539E-09
  45      +      ,-0.976788E-11, 0.216911E-12, 0.521380E-09,-0.442265E-09
  46      +      , 0.141753E-09,-0.190826E-10, 0.114038E-11,-0.242085E-13/
  47       DATA C2/0.572943E-10,-0.296824E-10, 0.630217E-11,-0.623179E-12
  48      +      , 0.211467E-13,-0.143579E-10,-0.137247E-11, 0.118670E-11
  49      +      ,-0.793091E-13, 0.124745E-14,-0.269884E-10, 0.125314E-10
  50      +      ,-0.239259E-11, 0.181151E-12,-0.470277E-14,-0.342454E-11
  51      +      , 0.976666E-12,-0.236792E-12, 0.213290E-13,-0.607799E-15
  52      +      ,-0.748844E-12, 0.178214E-12,-0.226827E-13, 0.148441E-14
  53      +      ,-0.367972E-16, 0.840330E-12, 0.820025E-11,-0.294797E-11
  54      +      , 0.294669E-12,-0.970294E-14,-0.830636E-12,-0.309273E-11
  55      +      , 0.124169E-11,-0.135879E-12, 0.481683E-14, 0.438223E-12
  56      +      , 0.259162E-12,-0.149284E-12, 0.180170E-13,-0.677948E-15/
  57 C.
  58 C.    ------------------------------------------------------------------
  59 C.
  60       GPRSGM=0.
  61       CUT=CCUT
  62       IF(CUT.LT.ECMIN) CUT=ECMIN
  63 C
  64       E=T+EMMU
  65       ECMAX=E-CONMX*Z**0.333333
  66       IF(CUT.GE.ECMAX) GOTO 99
  67 C
  68       X=LOG(E/EMMU)
  69       Y=LOG(CUT/(VS*E))
  70 C
  71       S=0.
  72       YY=1.
  73       DO 30 I=1,2
  74          XX=1.
  75          DO 20 J=1,6
  76             K=6*I+J-6
  77             S=S+C(K)*XX*YY
  78             XX=XX*X
  79   20     CONTINUE
  80          YY=YY*Y
  81   30  CONTINUE
  82       DO 50 I=3,6
  83          XX=1.
  84          DO 40 J=1,6
  85             K=6*I+J-6
  86             IF(Y.LE.0.) THEN
  87                S=S+C(K)*XX*YY
  88             ELSE
  89                S=S+C(K+24)*XX*YY
  90             ENDIF
  91             XX=XX*X
  92   40     CONTINUE
  93          YY=YY*Y
  94   50  CONTINUE
  95       SS=0.
  96       YY=1.
  97       DO 70 I=1,2
  98          XX=1.
  99          DO 60 J=1,5
 100             K=5*I+J+55
 101             SS=SS+C(K)*XX*YY
 102             XX=XX*X
 103   60     CONTINUE
 104          YY=YY*Y
 105   70  CONTINUE
 106       DO 90 I=3,5
 107          XX=1.
 108          DO 80 J=1,5
 109             K=5*I+J+55
 110             IF(Y.LE.0.) THEN
 111                SS=SS+C(K)*XX*YY
 112             ELSE
 113                SS=SS+C(K+15)*XX*YY
 114             ENDIF
 115             XX=XX*X
 116   80     CONTINUE
 117         YY=YY*Y
 118   90  CONTINUE
 119 C
 120       S=S+Z*SS
 121       IF(S.LE.0.) GOTO 99
 122 C
 123 C     DE/DX SHOULD BE MONOTON INCREASING AS A
 124 C     FUNCTION OF THE CUT
 125 C     SOLUTION: LIN. INTERPOLATION FOR 0.2*ECMAX<CUT<ECMAX
 126 C
 127       FAC=2.*(LOG(ECMAX/CUT))**ALFA
 128       FAC=Z*(Z+AKSI*(1.+GAM*LOG(Z)))*FAC
 129       GPRSGM=FAC*S
 130 C
 131   99  RETURN
 132       END