[u/mrichter/AliRoot.git] / GEANT321 / gphys / gphsg2.F

*
* $Id$
*
* $Log$
* Revision 1.1.1.1  1995/10/24 10:21:30  cernlib
* Geant
*
*
#include "geant321/pilot.h"
*CMZ :  3.21/02 29/03/94  15.41.22  by  S.Giani
*-- Author :
      FUNCTION GPHSG2(E)
C.
C.    ******************************************************************
C.    *                                                                *
C.    *       FUNCTION TO COMPUTE THE PHOTOEFFECT TOTAL CROSS-SECTION  *
C.    *       AS A FUNCTION OF Z AND E                                 *
C.    *                                                                *
C.    *    ==>CALLED BY : special dE/dx                                *
C.    *                                                                *
C.    *    (1) Sandia parametrizsation is used;                        *
C.    *    (2) GPHSG2 in Megabarns                                     *
C.    *    (3) E in GeV                                                *
C.    *                                                                *
C.    *     J. Chwastowski 31.03.93                                    *
C.    ******************************************************************
C.
#include "geant321/gcbank.inc"
#include "geant321/gcjloc.inc"
#include "geant321/gconsp.inc"
#include "geant321/gcmate.inc"
#include "geant321/gc10ev.inc"
#if !defined(CERNLIB_SINGLE)
      DOUBLE PRECISION EINV,ECUR,ONE,RES,ZERO
#endif
      PARAMETER (ONE=1,ZERO=0)
C.
C.    ------------------------------------------------------------------
C.
      RES = 0.
      IF(E.LT.G10EV) GO TO 30
C Use Sandia data
      JPHXS  = LQ(JPHOT-1)
      NZ     = Q(JPHXS+1)
      ECUR   = E*1E6
      EINV   = ONE/ECUR
      JWEIGH = JPHXS+2*NZ+1
      DO 20 JZ=1,NZ
         JPHFN   = LQ(JPHXS-JZ)
         IPOINT  = JPHFN+1
         IMAX    = Q(IPOINT)
         IPOINT  = IPOINT-4
         DO 10 I = 1,IMAX
            IPOINT = IPOINT+5
            IF(ECUR.LT.Q(IPOINT)) THEN
               J   = IPOINT+1
               RES = RES+Q(JWEIGH+JZ)*
     +         EINV*(Q(J)+EINV*(Q(J+1)+EINV*(Q(J+2)+EINV*Q(J+3))))
               GO TO 20
            ENDIF
   10    CONTINUE
   20 CONTINUE
C RES value is in cm**2/g
C Now in Megabarns
   30 GPHSG2 = MAX(RES,ZERO)*A/AVO*1E-6
C
      END
Commit	Line	Data
fe4da5cc	1	*
	2	* $Id$
	3	*
	4	* $Log$
	5	* Revision 1.1.1.1 1995/10/24 10:21:30 cernlib
	6	* Geant
	7	*
	8	*
	9	#include "geant321/pilot.h"
	10	*CMZ : 3.21/02 29/03/94 15.41.22 by S.Giani
	11	*-- Author :
	12	FUNCTION GPHSG2(E)
	13	C.
	14	C. ******************************************************************
	15	C. * *
	16	C. * FUNCTION TO COMPUTE THE PHOTOEFFECT TOTAL CROSS-SECTION *
	17	C. * AS A FUNCTION OF Z AND E *
	18	C. * *
	19	C. * ==>CALLED BY : special dE/dx *
	20	C. * *
	21	C. * (1) Sandia parametrizsation is used; *
	22	C. * (2) GPHSG2 in Megabarns *
	23	C. * (3) E in GeV *
	24	C. * *
	25	C. * J. Chwastowski 31.03.93 *
	26	C. ******************************************************************
	27	C.
	28	#include "geant321/gcbank.inc"
	29	#include "geant321/gcjloc.inc"
	30	#include "geant321/gconsp.inc"
	31	#include "geant321/gcmate.inc"
	32	#include "geant321/gc10ev.inc"
	33	#if !defined(CERNLIB_SINGLE)
	34	DOUBLE PRECISION EINV,ECUR,ONE,RES,ZERO
	35	#endif
	36	PARAMETER (ONE=1,ZERO=0)
	37	C.
	38	C. ------------------------------------------------------------------
	39	C.
	40	RES = 0.
	41	IF(E.LT.G10EV) GO TO 30
	42	C Use Sandia data
	43	JPHXS = LQ(JPHOT-1)
	44	NZ = Q(JPHXS+1)
	45	ECUR = E*1E6
	46	EINV = ONE/ECUR
	47	JWEIGH = JPHXS+2*NZ+1
	48	DO 20 JZ=1,NZ
	49	JPHFN = LQ(JPHXS-JZ)
	50	IPOINT = JPHFN+1
	51	IMAX = Q(IPOINT)
	52	IPOINT = IPOINT-4
	53	DO 10 I = 1,IMAX
	54	IPOINT = IPOINT+5
	55	IF(ECUR.LT.Q(IPOINT)) THEN
	56	J = IPOINT+1
	57	RES = RES+Q(JWEIGH+JZ)*
	58	+ EINV(Q(J)+EINV(Q(J+1)+EINV(Q(J+2)+EINVQ(J+3))))
	59	GO TO 20
	60	ENDIF
	61	10 CONTINUE
	62	20 CONTINUE
	63	C RES value is in cm**2/g
	64	C Now in Megabarns
65	30 GPHSG2 = MAX(RES,ZERO)A/AVO1E-6
66	C
67	END