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cafagna |
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cafagna |
3.2 |
* $Id: gfluct.F,v 3.1.1.1 2002/07/11 16:02:14 cafagna Exp $ |
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* |
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* $Log: gfluct.F,v $ |
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* Revision 3.1.1.1 2002/07/11 16:02:14 cafagna |
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* First GPAMELA release on CVS |
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cafagna |
3.1 |
* |
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* |
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#if !defined(GPAMELA_NOGFLUCT) |
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*CMZ : 3.00/00 22/12/2000 19.00.22 by Marialuigia Ambriola |
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*CMZ : 2.01/00 06/03/2000 13.07.03 by Francesco Cafagna |
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*CMZ : 2.00/00 03/03/2000 15.39.06 by Francesco Cafagna |
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*CMZ : 1.02/00 18/03/97 18.25.28 by Francesco Cafagna |
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*CMZ : 3.21/02 29/03/94 15.41.21 by S.Giani |
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*-- Author : |
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SUBROUTINE GFLUCT(DEMEAN,DE) |
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C. |
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C. ****************************************************************** |
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C. * * |
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C. * Subroutine to decide which method is used to simulate * |
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C. * the straggling around the mean energy loss. * |
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C. * * |
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C. * * |
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C. * DNMIN: <---------->1<-------->30<--------->50<---------> * |
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C. * * |
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C. * LOSS=2 : * |
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C. * STRA=0 <----------GLANDZ-------------------><--GLANDO--> * |
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C. * LOSS=1,3: * |
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C. * STRA=0 <---------------------GLANDZ--------------------> * |
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C. * * |
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C. * STRA=1 <-----------PAI---------------------><--GLANDZ--> * |
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#if defined(GPAMELA_ASHO) |
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C. * STRA=2 <---PAI----><---ASHO---><----PAI----><--GLANDZ--> * |
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C. * * |
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#endif |
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C. * SSTR=1: Silicon straggling, gaussian straggling * |
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C. * * |
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C. * DNMIN : an estimation of the number of collisions * |
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C. * with energy close to the ionization energy * |
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C. * (see PHYS333) * |
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C. * * |
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C. * Input : DEMEAN (mean energy loss) * |
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C. * Output : DE (energy loss in the current step) * |
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C. * * |
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C. * ==>Called by : GTELEC,GTMUON,GTHADR * |
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C. * * |
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C. ****************************************************************** |
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C. |
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#include "gcbank.inc" |
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#include "gcjloc.inc" |
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#include "gconsp.inc" |
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#include "gcmate.inc" |
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#include "gccuts.inc" |
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#include "gckine.inc" |
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#include "gcmulo.inc" |
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#include "gcphys.inc" |
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#include "gctrak.inc" |
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* |
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* |
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* *** VARIABLE FOR SILICON STRAGGLING |
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#include "gpkey.inc" |
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#include "gppmat.inc" |
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INTEGER NMAT,NWNMAT |
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CHARACTER*20 CHNMAT, |
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REAL ANMAT,ZNMAT,DNMAT,RNMAT,ABNMAT,UBNMAT(NWMMAT),GRNDM0,GPGAUS |
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* |
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PARAMETER (EULER=0.577215,GAM1=EULER-1) |
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PARAMETER (P1=.60715,P2=.67794,P3=.52382E-1,P4=.94753, |
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+ P5=.74442,P6=1.1934) |
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PARAMETER (DGEV=0.153536 E-3, DNLIM=50) |
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#if defined(GPAMELA_ASHO) |
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PARAMETER (ASHMIN=1,ASHMAX=30) |
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#endif |
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DIMENSION RNDM(2) |
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FLAND(X) = P1+P6*X+(P2+P3*X)*EXP(P4*X+P5) |
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* |
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IF(STEP.LE.0) THEN |
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DE=DEMEAN |
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ELSE |
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DEDX = DEMEAN/STEP |
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POTI=Q(JPROB+9) |
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IF(ISTRA.EQ.0.AND.ILOSS.NE.2) THEN |
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CALL GLANDZ(Z,STEP,VECT(7),GETOT,DEDX,DE,POTI,Q(JPROB+10)) |
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ELSE |
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* |
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* *** mean ionization potential (GeV) |
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* POTI=16E-9*Z**0.9 |
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* |
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GAMMA = GETOT/AMASS |
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BETA = VECT(7)/GETOT |
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BET2 = BETA**2 |
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* |
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* *** low energy transfer |
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XI = DGEV*CHARGE**2*STEP*DENS*Z/(A*BET2) |
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* |
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* *** regime |
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* *** ISTRA = 1 --> PAI + URBAN |
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#if defined(GPAMELA_ASHO) |
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* *** ISTRA = 2 --> PAI + URBAN + ASHO |
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#endif |
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DNMIN = MIN(XI,DEMEAN)/POTI |
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* |
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IF (ISTRA.EQ.0) THEN |
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IF(DNMIN.GE.DNLIM) THEN |
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* |
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* Energy straggling using Gaussian, Landau & Vavilov theories. |
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* |
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* STEP = current step-length (cm) |
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* |
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* DELAND = DE/DX - <DE/DX> (GeV) |
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* |
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* Author : G.N. Patrick |
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* |
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IF(STEP.LT.1.E-7)THEN |
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DELAND=0. |
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ELSE |
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* |
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* Maximum energy transfer to atomic electron (GeV). |
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ETA = BETA*GAMMA |
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RATIO = EMASS/AMASS |
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* |
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* Calculate Kappa significance ratio. |
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* EMAX=(2*EMASS*ETA**2)/(1+2*RATIO*GAMMA+RATIO**2) |
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* CAPPA = XI/EMAX |
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CAPPA = XI*(1+2*RATIO*GAMMA+RATIO**2)/(2*EMASS* |
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+ ETA**2) |
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IF (CAPPA.GE.10.) THEN |
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* |
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* +-----------------------------------+ |
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* I Sample from Gaussian distribution I |
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* +-----------------------------------+ |
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SIGMA = XI*SQRT((1.-0.5*BET2)/CAPPA) |
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CALL GRNDM(RNDM,2) |
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F1 = -2.*LOG(RNDM(1)) |
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DELAND = SIGMA*SQRT(F1)*COS(TWOPI*RNDM(2)) |
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ELSE |
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XMEAN = -BET2-LOG(CAPPA)+GAM1 |
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IF (CAPPA.LT.0.01) THEN |
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XLAMX = FLAND(XMEAN) |
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* +---------------------------------------------------------------+ |
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* I Sample lambda variable from Kolbig/Schorr Landau distribution I |
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* +---------------------------------------------------------------+ |
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* 10 CALL GRNDM(RNDM,1) |
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* IF( RNDM(1) .GT. 0.980 ) GO TO 10 |
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* XLAMB = GLANDR(RNDM(1)) |
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* +---------------------------------------------------------------+ |
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* I Sample lambda variable from James/Hancock Landau distribution I |
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* +---------------------------------------------------------------+ |
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10 CALL GLANDG(XLAMB) |
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IF(XLAMB.GT.XLAMX) GO TO 10 |
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ELSE |
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* +---------------------------------------------------------+ |
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* I Sample lambda variable (Landau not Vavilov) from I |
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* I Rotondi&Montagna&Kolbig Vavilov distribution I |
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* +---------------------------------------------------------+ |
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CALL GRNDM(RNDM,1) |
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XLAMB = GVAVIV(CAPPA,BET2,RNDM(1)) |
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ENDIF |
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* |
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* Calculate DE/DX - <DE/DX> |
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DELAND = XI*(XLAMB-XMEAN) |
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ENDIF |
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ENDIF |
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DE = DEMEAN + DELAND |
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ELSE |
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CALL GLANDZ(Z,STEP,VECT(7),GETOT,DEDX,DE,POTI, |
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+ Q(JPROB+ 10)) |
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ENDIF |
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ELSE IF (ISTRA.LE.2) THEN |
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IF(DNMIN.GE.DNLIM) THEN |
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CALL GLANDZ(Z,STEP,VECT(7),GETOT,DEDX,DE,POTI, |
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+ Q(JPROB+ 10)) |
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ELSE |
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NMEC = NMEC+1 |
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LMEC(NMEC)=109 |
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#if defined(GPAMELA_ASHO) |
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IF (DNMIN.GE.ASHMIN.AND.DNMIN.LT.ASHMAX .AND.ISTRA.EQ |
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+ .2) THEN |
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CALL GASHO(VECT(7),AMASS,STEP,DE) |
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ELSE |
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DE = GSTREN(GAMMA,DCUTE,STEP) |
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ENDIF |
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#endif |
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#if !defined(GPAMELA_ASHO) |
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DE = GSTREN(GAMMA,DCUTE,STEP) |
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#endif |
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* |
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* *** Add brem losses to ionisation |
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IF(ITRTYP.EQ.2) THEN |
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JBASE = LQ(JMA-1)+2*NEK1+IEKBIN |
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DE = DE +(1.-GEKRAT)*Q(JBASE)+GEKRAT*Q(JBASE+1) |
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ELSEIF(ITRTYP.EQ.5) THEN |
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JBASE = LQ(JMA-2)+NEK1+IEKBIN |
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DE = DE +(1.-GEKRAT)*Q(JBASE)+GEKRAT*Q(JBASE+1) |
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ENDIF |
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ENDIF |
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ENDIF |
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ENDIF |
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* |
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* *** Add straggling specifically for Silicon By P.Papini and F.S.Cafagna |
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* |
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* change in de/dx with gaussian convolution |
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* see Hall paper: NIM 220 (1984) 356. |
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* |
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IF(ISSTR.EQ.1) THEN |
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* |
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* *** First of all get a look to the DELTA2 and SIGMA2 parameter |
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CALL GFMATE(NMAT,CHNMAT,ANMAT,ZNMAT,DNMAT,RNMAT,ABNMAT, |
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+ UBNMAT,NWNMAT) |
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* |
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* *** Save user infos |
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DELTA2 = UBNMAT(1) |
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SIGMA2 = DELTA2*STEP |
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GRNDM0 = GPGAUS(0.) |
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* Gaussian energy spread... |
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* Delta is in GeV^2/cm |
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DE = DE + GRNDM0 * SQRT(SIGMA2) |
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ENDIF |
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ENDIF |
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* |
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END |
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