[u/mrichter/AliRoot.git] / GEANT321 / gphys / gphsgp.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 GPHSGP(IELEM,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) GPHSGP in cm**/g                                        *
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/gcunit.inc"
#include "geant321/gc10ev.inc"
#if !defined(CERNLIB_SINGLE)
      DOUBLE PRECISION EINV,ECUR,ONE
#endif
      PARAMETER (ONE=1)
C.
C.    ------------------------------------------------------------------
C.
      RES = 0.
      IF(E.LT.G10EV) GO TO 20
C Use Sandia data
      JPHXS  = LQ(JPHOT-1)
      IF(IELEM.GT.IQ(JPHXS-2)) THEN
         WRITE(CHMAIL,10010) IELEM, IQ(JPHXS-2)
10010 FORMAT(' *** GPHSGP : element N ',I6,' requested, ',
     +'but only ',I6,' elements in present mixture')
         CALL GMAIL(0,0)
         GOTO 20
      ENDIF
      JPHXSI = LQ(JPHXS-IELEM)
      IPOINT = JPHXSI+1
      IMAX = Q(IPOINT)
      IPOINT = IPOINT+1
      ECUR = E*1.E6
      IF(ECUR.LT.Q(IPOINT)) GO TO 20
      EINV = ONE/ECUR
      DO 10 I = 2,IMAX
         IPOINT = IPOINT+5
         IF(ECUR.LT.Q(IPOINT)) THEN
            J = IPOINT+1
            RES = EINV*(Q(J)+EINV*(Q(J+1)+EINV*(Q(J+2)+EINV*Q(J+3))))
            GO TO 20
         ENDIF
   10 CONTINUE
C This value is in cm**2/g
   20 GPHSGP = MAX(RES,0.)
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 GPHSGP(IELEM,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) GPHSGP in cm*/g
	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/gcunit.inc"
	32	#include "geant321/gc10ev.inc"
	33	#if !defined(CERNLIB_SINGLE)
	34	DOUBLE PRECISION EINV,ECUR,ONE
	35	#endif
	36	PARAMETER (ONE=1)
	37	C.
	38	C. ------------------------------------------------------------------
	39	C.
	40	RES = 0.
	41	IF(E.LT.G10EV) GO TO 20
	42	C Use Sandia data
	43	JPHXS = LQ(JPHOT-1)
	44	IF(IELEM.GT.IQ(JPHXS-2)) THEN
	45	WRITE(CHMAIL,10010) IELEM, IQ(JPHXS-2)
	46	10010 FORMAT(' *** GPHSGP : element N ',I6,' requested, ',
	47	+'but only ',I6,' elements in present mixture')
	48	CALL GMAIL(0,0)
	49	GOTO 20
	50	ENDIF
	51	JPHXSI = LQ(JPHXS-IELEM)
	52	IPOINT = JPHXSI+1
	53	IMAX = Q(IPOINT)
	54	IPOINT = IPOINT+1
	55	ECUR = E*1.E6
	56	IF(ECUR.LT.Q(IPOINT)) GO TO 20
	57	EINV = ONE/ECUR
	58	DO 10 I = 2,IMAX
	59	IPOINT = IPOINT+5
	60	IF(ECUR.LT.Q(IPOINT)) THEN
	61	J = IPOINT+1
	62	RES = EINV(Q(J)+EINV(Q(J+1)+EINV(Q(J+2)+EINVQ(J+3))))
	63	GO TO 20
	64	ENDIF
65	10 CONTINUE
66	C This value is in cm**2/g
67	20 GPHSGP = MAX(RES,0.)
68	C
69	END