| 1 | SUBROUTINE BHABHA
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| 2 | C VERSION 4.00 -- 26 JAN 1986/1900
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| 3 | C******************************************************************
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| 4 | C DISCRETE BHABHA SCATTERING (A CALL TO THIS ROUTINE) HAS BEEN
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| 5 | C ARBITRARILY DEFINED AND CALCULATED TO MEAN BHABHA SCATTERINGS
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| 6 | C WHICH IMPART TO THE SECONDARY ELECTRON SUFFICIENT ENERGY THAT
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| 7 | C IT BE TRANSPORTED DISCRETELY, I.E. E=AE OR T=TE. IT IS NOT
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| 8 | C GUARANTEED THAT THE FINAL POSITRON WILL HAVE THIS MUCH ENERGY
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| 9 | C HOWEVER. THE EXACT BHABHA DIFFERENTIAL CROSS SECTION IS USED.
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| 10 | C******************************************************************
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| 11 | DOUBLE PRECISION PEIP,PEKSE2,PESE1,PESE2
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| 12 | DOUBLE PRECISION PEKIN,PEKINI,H1,DCOSTH
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| 13 | *KEEP,RANDPA.
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| 14 | COMMON /RANDPA/ FAC,U1,U2,RD,NSEQ,ISEED,KNOR
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| 15 | DOUBLE PRECISION FAC,U1,U2
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| 16 | REAL RD(3000)
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| 17 | INTEGER ISEED(103,10),NSEQ
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| 18 | LOGICAL KNOR
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| 19 | *KEEP,RUNPAR.
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| 20 | COMMON /RUNPAR/ FIXHEI,THICK0,HILOECM,HILOELB,
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| 21 | * STEPFC,NRRUN,NSHOW,PATAPE,MONIIN,
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| 22 | * MONIOU,MDEBUG,NUCNUC,
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| 23 | * CETAPE,
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| 24 | * SHOWNO,ISHW,NOPART,NRECS,NBLKS,MAXPRT,NDEBDL,
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| 25 | * N1STTR,MDBASE,
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| 26 | * DEBDEL,DEBUG,FDECAY,FEGS,FIRSTI,FIXINC,FIXTAR,
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| 27 | * FIX1I,FMUADD,FNKG,FPRINT,FDBASE
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| 28 | * ,GHEISH,GHESIG
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| 29 | COMMON /RUNPAC/ DSN,HOST,USER
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| 30 | DOUBLE PRECISION FIXHEI,THICK0,HILOECM,HILOELB
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| 31 | REAL STEPFC
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| 32 | INTEGER NRRUN,NSHOW,PATAPE,MONIIN,MONIOU,MDEBUG,NUCNUC,
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| 33 | * SHOWNO,ISHW,NOPART,NRECS,NBLKS,MAXPRT,NDEBDL,
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| 34 | * N1STTR,MDBASE
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| 35 | INTEGER CETAPE
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| 36 | CHARACTER*79 DSN
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| 37 | CHARACTER*20 HOST,USER
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| 38 |
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| 39 | LOGICAL DEBDEL,DEBUG,FDECAY,FEGS,FIRSTI,FIXINC,FIXTAR,
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| 40 | * FIX1I,FMUADD,FNKG,FPRINT,FDBASE
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| 41 | * ,GHEISH,GHESIG
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| 42 | *KEEP,STACKE.
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| 43 | COMMON/STACKE/ E,TIME,X,Y,Z,U,V,W,DNEAR,IQ,IGEN,IR,IOBS,LPCTE,NP
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| 44 | DOUBLE PRECISION E(60),TIME(60)
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| 45 | REAL X(60),Y(60),Z(60),U(60),V(60),W(60),DNEAR(60)
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| 46 | INTEGER IQ(60),IGEN(60),IR(60),IOBS(60),LPCTE(60),NP
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| 47 | *KEND.
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| 48 | COMMON/THRESH/RMT2,RMSQ,ESCD2,AP,API,AE,UP,UE,TE,THMOLL
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| 49 | COMMON/UPHIOT/THETA,SINTHE,COSTHE,SINPHI, COSPHI,PI,TWOPI,PI5D2
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| 50 | DOUBLE PRECISION PZERO,PRM,PRMT2,RMI,VC
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| 51 | COMMON/USEFUL/PZERO,PRM,PRMT2,RMI,VC,RM,MEDIUM,MEDOLD,IBLOBE,ICALL
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| 52 | COMMON/ACLOCK/NCLOCK,JCLOCK
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| 53 | C_____IF (NCLOCK.GT.JCLOCK) THEN
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| 54 | C______WRITE(MDEBUG,* )' BHABHA:NP=',NP,' IR=',IR(NP),' IOBS=',IOBS(NP)
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| 55 | C______CALL AUSGB2
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| 56 | C_____END IF
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| 57 | PEIP=E(NP)
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| 58 | EIP=PEIP
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| 59 | PEKIN=PEIP-PRM
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| 60 | EKIN=PEKIN
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| 61 | PEKINI=1./PEKIN
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| 62 | EKINI=PEKINI
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| 63 | T0=EKIN*RMI
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| 64 | E0=T0+1.
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| 65 | YY=1./(T0+2.)
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| 66 | E02=E0*E0
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| 67 | BETAI2=E02/(E02-1.)
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| 68 | EP0=TE*EKINI
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| 69 | EP0C=1.-EP0
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| 70 | Y2=YY*YY
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| 71 | YP=1.-2.*YY
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| 72 | YP2=YP*YP
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| 73 | B4=YP2*YP
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| 74 | B3=B4+YP2
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| 75 | B2=YP*(3.+Y2)
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| 76 | B1=2.-Y2
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| 77 | 341 CONTINUE
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| 78 | CALL RMMAR(RD,2,2)
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| 79 | RNNO03=RD(1)
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| 80 | RNNO04=RD(2)
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| 81 | BR=EP0/(1.-EP0C*RNNO03)
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| 82 | REJF2=EP0C*(BETAI2-BR*(B1-BR*(B2-BR*(B3-BR*B4))))
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| 83 | IF((RNNO04.LE.REJF2))GO TO342
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| 84 | GO TO 341
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| 85 | 342 CONTINUE
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| 86 | IF (BR.LT.0.5) THEN
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| 87 | IQ(NP+1)=3
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| 88 | ELSE
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| 89 | IQ(NP)=3
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| 90 | IQ(NP+1)=2
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| 91 | BR=1.-BR
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| 92 | END IF
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| 93 | BR=MAX(BR,0.0)
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| 94 | PEKSE2=BR*EKIN
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| 95 | PESE1=PEIP-PEKSE2
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| 96 | PESE2=PEKSE2+PRM
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| 97 | E(NP)=PESE1
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| 98 | E(NP+1)=PESE2
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| 99 | H1=(PEIP+PRM)*PEKINI
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| 100 | DCOSTH=MIN(H1*(PESE1-PRM)/(PESE1+PRM),1.D0)
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| 101 | SINTHE=SQRT(1.D0-DCOSTH)
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| 102 | COSTHE=SQRT(DCOSTH)
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| 103 | CALL UPHI(2,1)
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| 104 | NP=NP+1
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| 105 | DCOSTH=MIN(H1*(PESE2-PRM)/(PESE2+PRM),1.D0)
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| 106 | SINTHE=-SQRT(1.D0-DCOSTH)
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| 107 | COSTHE=SQRT(DCOSTH)
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| 108 | CALL UPHI(3,2)
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| 109 | RETURN
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| 110 | END
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