GEANT321/gheisha/nbanh.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:20:58  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.38  by  S.Giani
  11 *-- Author :
  12       SUBROUTINE NBANH(NOPT)
  13 C
  14 C *** ANTI NEUTRON ANNIHILATION AT REST ***
  15 C *** NVE 04-MAR-1988 CERN GENEVA ***
  16 C
  17 C ORIGIN : H.FESEFELDT (09-JULY-1987)
  18 C
  19 C NOPT=0    NO ANNIHILATION
  20 C NOPT=1    ANNIH.IN PI+ PI-
  21 C NOPT=2    ANNIH.IN PI0 PI0
  22 C NOPT=3    ANNIH.IN PI+ PI0
  23 C NOPT=4    ANNIH.IN GAMMA GAMMA
  24 C
  25 #include "geant321/s_defcom.inc"
  26 C
  27       DIMENSION BRR(3)
  28       DIMENSION RNDM(3)
  29       DATA BRR/0.125,0.25,0.50/
  30 C
  31       PV(1,1)=0.
  32       PV(2,1)=0.
  33       PV(3,1)=0.
  34       PV(4,1)=ABS(RMASS(17))
  35       PV(5,1)=RMASS(17)
  36       PV(6,1)=0.
  37       PV(7,1)=TOF
  38       PV(8,1)=IPART
  39       PV(9,1)=0.
  40       PV(10,1)=USERW
  41       IER(85)=IER(85)+1
  42       ISW=1
  43       CALL GRNDM(RNDM,1)
  44       RAN=RNDM(1)
  45       IF(RAN.GT.BRR(1)) ISW=2
  46       IF(RAN.GT.BRR(2)) ISW=3
  47       IF(RAN.GT.BRR(3)) ISW=4
  48       NOPT=ISW
  49 C**
  50 C**  EVAPORATION
  51 C**
  52       CALL COMPO
  53       RMNVE1=RMASS(7)
  54       RMNVE2=RMASS(9)
  55       IF (ISW .EQ. 2) RMNVE1=RMASS(8)
  56       IF (ISW .EQ. 2) RMNVE2=RMASS(8)
  57       IF (ISW .EQ. 3) RMNVE2=RMASS(8)
  58       IF (ISW .EQ. 4) RMNVE1=RMASS(1)
  59       IF (ISW .EQ. 4) RMNVE2=RMASS(1)
  60       EK=RMASS(16)+ABS(RMASS(17))-RMNVE1-RMNVE2
  61       TKIN=EXNU(EK)
  62       EK=EK-TKIN
  63       IF(EK.LT.0.0001) EK=0.0001
  64       EK=EK/2.
  65       EN=EK+(RMNVE1+RMNVE2)/2.0
  66       S=AMAS*AMAS+RMASS(16)**2+2.0*RMASS(16)*EN
  67       RS=SQRT(S)
  68       PCM=SQRT(ABS(EN*EN-RMNVE1*RMNVE2))
  69       CALL GRNDM(RNDM,2)
  70       PHI=2.*PI*RNDM(1)
  71       COST=-1.+2.*RNDM(2)
  72       SINT=SQRT(ABS(1.-COST*COST))
  73       PV(1,2)=PCM*SINT*COS(PHI)
  74       PV(2,2)=PCM*SINT*SIN(PHI)
  75       PV(3,2)=PCM*COST
  76       DO 1 I=1,3
  77     1 PV(I,3)=-PV(I,2)
  78       PV(5,2)=RMNVE1
  79       PV(5,3)=RMNVE2
  80       IF(ISW.LE.3) GOTO 2
  81       PV(5,2)=0.
  82       PV(5,3)=0.
  83     2 PV(4,2)=SQRT(PV(5,2)**2+PCM**2)
  84       PV(4,3)=SQRT(PV(5,3)**2+PCM**2)
  85       PV(7,2)=TOF
  86       PV(7,3)=TOF
  87       PV(9,2)=0.
  88       PV(9,3)=0.
  89       PV(10,2)=0.
  90       PV(10,3)=0.
  91       GOTO (21,22,23,24), ISW
  92    21 PV(6,2)=1.
  93       PV(6,3)=-1.
  94       PV(8,2)=7.
  95       PV(8,3)=9.
  96       GOTO 25
  97    22 PV(6,2)=0.
  98       PV(6,3)=0.
  99       PV(8,2)=8.
 100       PV(8,3)=8.
 101       GOTO 25
 102    23 PV(6,2)=1.
 103       PV(6,3)=0.
 104       PV(8,2)=7.
 105       PV(8,3)=8.
 106       GOTO 25
 107    24 PV(6,2)=0.
 108       PV(6,3)=0.
 109       PV(8,2)=1.
 110       PV(8,3)=1.
 111    25 NT=3
 112       IF(ATNO2.LT.1.5) GOTO 40
 113       AFC=0.312+0.200*LOG(LOG(S))+S**1.5/6000.
 114 C     TARG=AFC*(ATNO2**0.33 -1.0)
 115       CFA=0.025*((ATNO2-1.)/120.)*EXP(-(ATNO2-1.)/120.)
 116       TARG=1.
 117       TEX=ENP(1)
 118       IF(TEX.LT.0.001) GOTO 445
 119       BLACK=(1.5+1.25*TARG)*ENP(1)/(ENP(1)+ENP(3))
 120       CALL POISSO(BLACK,NBL)
 121       IF(IFIX(TARG)+NBL.GT.ATNO2) NBL=ATNO2-TARG
 122       IF(NT+NBL.GT.MXGKPV-2) NBL=MXGKPV-2-NT
 123       IF(NBL.LE.0) GOTO 445
 124       EKIN=TEX/NBL
 125       EKIN2=0.
 126       CALL STEEP(XX)
 127       DO 441 I=1,NBL
 128       IF(NT.EQ.MXGKPV-2) GOTO 441
 129       IF(EKIN2.GT.TEX) GOTO 443
 130       CALL GRNDM(RNDM,1)
 131       RAN1=RNDM(1)
 132       CALL NORMAL(RAN2)
 133       EKIN1=-EKIN*LOG(RAN1)-CFA*(1.+0.5*RAN2)
 134       IF(EKIN1.LT.0.0) EKIN1=-0.010*LOG(RAN1)
 135       EKIN1=EKIN1*XX
 136       EKIN2=EKIN2+EKIN1
 137       IF(EKIN2.GT.TEX) EKIN1=TEX-(EKIN2-EKIN1)
 138       IF(EKIN1.LT.0.) EKIN1=0.001
 139       IPA1=16
 140       PNRAT=1.-ZNO2/ATNO2
 141       CALL GRNDM(RNDM,3)
 142       IF(RNDM(1).GT.PNRAT) IPA1=14
 143       NT=NT+1
 144       COST=-1.+RNDM(2)*2.
 145       SINT=SQRT(ABS(1.-COST*COST))
 146       PHI=TWPI*RNDM(3)
 147       IPA(NT)=-IPA1
 148       PV(5,NT)=ABS(RMASS(IPA1))
 149       PV(6,NT)=RCHARG(IPA1)
 150       PV(7,NT)=TOF
 151       PV(8,NT)=IPA1
 152       PV(9,NT)=0.
 153       PV(10,NT)=0.
 154       PV(4,NT)=EKIN1+PV(5,NT)
 155       PP=SQRT(ABS(PV(4,NT)**2-PV(5,NT)**2))
 156       PV(1,NT)=PP*SINT*SIN(PHI)
 157       PV(2,NT)=PP*SINT*COS(PHI)
 158       PV(3,NT)=PP*COST
 159   441 CONTINUE
 160   443 IF(ATNO2.LT.230.) GOTO 445
 161       IF(EK.GT.2.0) GOTO 445
 162       II=NT+1
 163       KK=0
 164       EKA=EK
 165       IF(EKA.GT.1.) EKA=EKA*EKA
 166       IF(EKA.LT.0.1) EKA=0.1
 167       IKA=IFIX(3.6/EKA)
 168       DO 444 I=1,NT
 169       II=II-1
 170       IF(IPA(II).NE.-14) GOTO 444
 171       IPA(II)=-16
 172       IPA1  = 16
 173       PV(5,II)=ABS(RMASS(IPA1))
 174       PV(6,II)=RCHARG(IPA1)
 175       PV(8,II)=IPA1
 176       KK=KK+1
 177       IF(KK.GT.IKA) GOTO 445
 178   444 CONTINUE
 179 C**
 180 C** THEN ALSO DEUTERONS, TRITONS AND ALPHAS
 181 C**
 182   445 TEX=ENP(3)
 183       IF(TEX.LT.0.001) GOTO 40
 184       BLACK=(1.5+1.25*TARG)*ENP(3)/(ENP(1)+ENP(3))
 185       CALL POISSO(BLACK,NBL)
 186       IF(NT+NBL.GT.MXGKPV-2) NBL=MXGKPV-2-NT
 187       IF(NBL.LE.0) GOTO 40
 188       EKIN=TEX/NBL
 189       EKIN2=0.
 190       CALL STEEP(XX)
 191       DO 442 I=1,NBL
 192       IF(NT.EQ.MXGKPV-2) GOTO 442
 193       IF(EKIN2.GT.TEX) GOTO 40
 194       CALL GRNDM(RNDM,1)
 195       RAN1=RNDM(1)
 196       CALL NORMAL(RAN2)
 197       EKIN1=-EKIN*LOG(RAN1)-CFA*(1.+0.5*RAN2)
 198       IF(EKIN1.LT.0.0) EKIN1=-0.010*LOG(RAN1)
 199       EKIN1=EKIN1*XX
 200       EKIN2=EKIN2+EKIN1
 201       IF(EKIN2.GT.TEX) EKIN1=TEX-(EKIN2-EKIN1)
 202       IF(EKIN1.LT.0.) EKIN1=0.001
 203       CALL GRNDM(RNDM,3)
 204       COST=-1.+RNDM(1)*2.
 205       SINT=SQRT(ABS(1.-COST*COST))
 206       PHI=TWPI*RNDM(2)
 207       RAN=RNDM(3)
 208       IPA(NT+1)=-30
 209       IF(RAN.GT.0.60) IPA(NT+1)=-31
 210       IF(RAN.GT.0.90) IPA(NT+1)=-32
 211       INVE=ABS(IPA(NT+1))
 212       PV(5,NT+1)=RMASS(INVE)
 213       NT=NT+1
 214       PV(6,NT)=RCHARG(INVE)
 215       PV(7,NT)=TOF
 216       PV(8,NT)=ABS(IPA(NT))
 217       PV(9,NT)=0.
 218       PV(10,NT)=0.
 219       PV(4,NT)=PV(5,NT)+EKIN1
 220       PP=SQRT(ABS(PV(4,NT)**2-PV(5,NT)**2))
 221       PV(1,NT)=PP*SINT*SIN(PHI)
 222       PV(2,NT)=PP*SINT*COS(PHI)
 223       PV(3,NT)=PP*COST
 224   442 CONTINUE
 225    40 INTCT=INTCT+1.
 226       CALL SETCUR(2)
 227       NTK=NTK+1
 228       IF(NT.EQ.2) GO TO 9999
 229       DO 50 I=3,NT
 230       IF(NTOT.LT.NSIZE/12) GOTO 43
 231       GO TO 9999
 232    43 CALL SETTRK(I)
 233    50 CONTINUE
 234       CALL LENGTX(3,PP)
 235       IF(NPRT(3))
 236      *WRITE(NEWBCD,1001) XEND,YEND,ZEND,P,NCH,PP,PV(6,3)
 237 1001  FORMAT(1H0,'NB ANNIHILATION AT REST  POSITION',3(1X,F8.2),1X,
 238      * 'PI MOMENTA,CHARGES',2(1X,F8.4,1X,F4.1))
 239 C
 240  9999 CONTINUE
 241       END