[u/mrichter/AliRoot.git] / GEANT321 / gphys / gbremm.F

*
* $Id$
*
* $Log$
* Revision 1.1.1.1  1995/10/24 10:21:22  cernlib
* Geant
*
*
#include "geant321/pilot.h"
*CMZ :  3.21/02 29/03/94  15.41.21  by  S.Giani
*-- Author :
      SUBROUTINE GBREMM
C.
C.    ******************************************************************
C.    *                                                                *
C.    *  Simulates discrete hard BREMSSTRAHLUNG by muons.              *
C.    *                                                                *
C.    *                                                                *
C.    *    ==>Called by : GTMUON                                       *
C.    *       Author     L.Urban  *********                            *
C.    *                                                                *
C.    ******************************************************************
C.
#include "geant321/gcbank.inc"
#include "geant321/gcphys.inc"
#include "geant321/gconsp.inc"
#include "geant321/gctrak.inc"
#include "geant321/gcjloc.inc"
#include "geant321/gckine.inc"
#include "geant321/gcking.inc"
#include "geant321/gccuts.inc"
      DIMENSION RNDM(2)
C.
C.    ------------------------------------------------------------------
C.
C             Ensure cut-off avoids infra-red catastrophe.
C
      EEM1   = GETOT
      IF (GEKIN.LE.BCUTM) GO TO 900
      KCASE  = NAMEC(9)
C
      C1   = Q(JPROB+31)
      C2   = Q(JPROB+32)
      C3   = Q(JPROB+33)
      VC   = BCUTM/EEM1
      VM   = 1.-C3/EEM1
      IF(VM.LE.0.)GO TO 900
      CREJ = C2/EEM1
C
  50  CALL GRNDM(RNDM,2)
      R    = RNDM(1)
      V    = VC*(VM/VC)**R
C
C             Compute rejection function
C
      V1   = 1.-V
      F1   = C1-LOG(1.+CREJ*V/V1)
      SCREJ= (V1+0.75*V*V)*F1/C1
      IF(RNDM(2).GT.SCREJ)GO TO 50
C
C             Photon energy
C
      EGAMMA=EEM1*V
C
C        CUT ON ENERGY THRESHOLD ?
C
      IF((IBREM.NE.1).OR.(EGAMMA.LE.CUTGAM)) THEN
          NGKINE = 0
          DESTEP = DESTEP + EGAMMA
          GO TO 800
      ENDIF
C
C             Generate emitted photon angles with respect to a Z-axis
C             defined along parent track. PHI is generated isotropically
C             and THETA is assigned a universal angular distribution
C
      THETA  = GBTETH(EEM1, AMASS, V)*AMASS/EEM1
      SINTH  = SIN(THETA)
      COSTH  = COS(THETA)
      CALL GRNDM(RNDM,1)
      PHI    = TWOPI*RNDM(1)
      COSPHI = COS(PHI)
      SINPHI = SIN(PHI)
C
C             Polar co-ordinates to momentum components.
C
      NGKINE = 1
      GKIN(1,1)=EGAMMA*SINTH*COSPHI
      GKIN(2,1)=EGAMMA*SINTH*SINPHI
      GKIN(3,1)=EGAMMA*COSTH
      GKIN(4,1)=EGAMMA
      GKIN(5,1)=1.
      TOFD(1)  =0.
      GPOS(1,1) = VECT(1)
      GPOS(2,1) = VECT(2)
      GPOS(3,1) = VECT(3)
C
C             Rotate photon into GEANT system
C
      CALL GVROT(VECT(4),GKIN)
C
C             Correct track for lost energy
C
  800 CONTINUE
      GEKIN = GEKIN - EGAMMA
      GETOT = GEKIN + AMASS
      VECT(7)=SQRT (ABS((GETOT+AMASS)*GEKIN))
      CALL GEKBIN
C
C             Update probabilities
C
  900 CALL GRNDM(RNDM,1)
      ZINTBR=-LOG(RNDM(1))
      SLBREM=SLENG
      STEPBR=BIG
C
      END
Commit	Line	Data
fe4da5cc	1	*
	2	* $Id$
	3	*
	4	* $Log$
	5	* Revision 1.1.1.1 1995/10/24 10:21:22 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 GBREMM
	13	C.
	14	C. ******************************************************************
	15	C. * *
	16	C. * Simulates discrete hard BREMSSTRAHLUNG by muons. *
	17	C. * *
	18	C. * *
	19	C. * ==>Called by : GTMUON *
	20	C. * Author L.Urban ********* *
	21	C. * *
	22	C. ******************************************************************
	23	C.
	24	#include "geant321/gcbank.inc"
	25	#include "geant321/gcphys.inc"
	26	#include "geant321/gconsp.inc"
	27	#include "geant321/gctrak.inc"
	28	#include "geant321/gcjloc.inc"
	29	#include "geant321/gckine.inc"
	30	#include "geant321/gcking.inc"
	31	#include "geant321/gccuts.inc"
	32	DIMENSION RNDM(2)
	33	C.
	34	C. ------------------------------------------------------------------
	35	C.
	36	C Ensure cut-off avoids infra-red catastrophe.
	37	C
	38	EEM1 = GETOT
	39	IF (GEKIN.LE.BCUTM) GO TO 900
	40	KCASE = NAMEC(9)
	41	C
	42	C1 = Q(JPROB+31)
	43	C2 = Q(JPROB+32)
	44	C3 = Q(JPROB+33)
	45	VC = BCUTM/EEM1
	46	VM = 1.-C3/EEM1
	47	IF(VM.LE.0.)GO TO 900
	48	CREJ = C2/EEM1
	49	C
	50	50 CALL GRNDM(RNDM,2)
	51	R = RNDM(1)
	52	V = VC(VM/VC)*R
	53	C
	54	C Compute rejection function
	55	C
	56	V1 = 1.-V
	57	F1 = C1-LOG(1.+CREJ*V/V1)
	58	SCREJ= (V1+0.75VV)*F1/C1
	59	IF(RNDM(2).GT.SCREJ)GO TO 50
	60	C
	61	C Photon energy
	62	C
	63	EGAMMA=EEM1*V
	64	C
65	C CUT ON ENERGY THRESHOLD ?
66	C
67	IF((IBREM.NE.1).OR.(EGAMMA.LE.CUTGAM)) THEN
68	NGKINE = 0
69	DESTEP = DESTEP + EGAMMA
70	GO TO 800
71	ENDIF
72	C
73	C Generate emitted photon angles with respect to a Z-axis
74	C defined along parent track. PHI is generated isotropically
75	C and THETA is assigned a universal angular distribution
76	C
77	THETA = GBTETH(EEM1, AMASS, V)*AMASS/EEM1
78	SINTH = SIN(THETA)
79	COSTH = COS(THETA)
80	CALL GRNDM(RNDM,1)
81	PHI = TWOPI*RNDM(1)
82	COSPHI = COS(PHI)
83	SINPHI = SIN(PHI)
84	C
85	C Polar co-ordinates to momentum components.
86	C
87	NGKINE = 1
88	GKIN(1,1)=EGAMMASINTHCOSPHI
89	GKIN(2,1)=EGAMMASINTHSINPHI
90	GKIN(3,1)=EGAMMA*COSTH
91	GKIN(4,1)=EGAMMA
92	GKIN(5,1)=1.
93	TOFD(1) =0.
94	GPOS(1,1) = VECT(1)
95	GPOS(2,1) = VECT(2)
96	GPOS(3,1) = VECT(3)
97	C
98	C Rotate photon into GEANT system
99	C
100	CALL GVROT(VECT(4),GKIN)
101	C
102	C Correct track for lost energy
103	C
104	800 CONTINUE
105	GEKIN = GEKIN - EGAMMA
106	GETOT = GEKIN + AMASS
107	VECT(7)=SQRT (ABS((GETOT+AMASS)*GEKIN))
108	CALL GEKBIN
109	C
110	C Update probabilities
111	C
112	900 CALL GRNDM(RNDM,1)
113	ZINTBR=-LOG(RNDM(1))
114	SLBREM=SLENG
115	STEPBR=BIG
116	C
117	END