[u/mrichter/AliRoot.git] / GEANT321 / erdecks / erland.F

*
* $Id$
*
* $Log$
* Revision 1.1.1.1  1996/03/06 15:37:34  mclareni
* Add geane321 source directories
*
*
#include "geant321/pilot.h"
*CMZ :  3.21/02 29/03/94  15.41.49  by  S.Giani
*-- Author :
      SUBROUTINE ERLAND (STEP, Z, A, RHO, P, E, XMASS, DEDX2)
C.
C.    ******************************************************************
C.    *                                                                *
C.    *  Calculates energy straggling using Gaussian theory in a step  *
C.    *                                                                *
C.    *  Input  STEP   =  current step-length (cm)                     *
C.    *         Z      =  Z of the material                            *
C.    *         A      =  A of the material                            *
C.    *         RHO    =  density of the material                      *
C.    *         P      =  momentum of the particle                     *
C.    *         E      =  energy   of the particle                     *
C.    *         XMASS  =  mass     of the particle                     *
C.    *                                                                *
C.    *  Output DEDX2  =  mean square of the straggling in G           *
C.    *                                                                *
C.    *    ==>Called by : ERTRCH                                       *
C.    *       Author    E.Nagy  *********                              *
C.    *       Original routine : GLANDO                                *
C.    *                                                                *
C.    ******************************************************************
C.
#include "geant321/gconst.inc"
*
      IF (STEP.LT.1.E-7) THEN
         DEDX2=0.
         RETURN
      ENDIF
*
*     Calculate xi factor (KeV).
      BETA   = P/E
      GAMMA  = E/XMASS
      XI     = (153.5*Z*STEP*RHO)/(A*BETA*BETA)
*
*     Maximum energy transfer to atomic electron (KeV).
      ETA    = BETA*GAMMA
      ETASQ  = ETA*ETA
      RATIO  = EMASS/XMASS
      F1     = 2.*EMASS*ETASQ
      F2     = 1.+2.*RATIO*GAMMA+RATIO*RATIO
      EMAX   = 1.E+6*F1/F2
*
*
* *** and now sigma**2  in GeV
*        gaussian
      DEDX2  = XI*EMAX*(1.-(BETA*BETA/2.))*1.E-12
*
      END
Commit	Line	Data
fe4da5cc	1	*
	2	* $Id$
	3	*
	4	* $Log$
	5	* Revision 1.1.1.1 1996/03/06 15:37:34 mclareni
	6	* Add geane321 source directories
	7	*
	8	*
	9	#include "geant321/pilot.h"
	10	*CMZ : 3.21/02 29/03/94 15.41.49 by S.Giani
	11	*-- Author :
	12	SUBROUTINE ERLAND (STEP, Z, A, RHO, P, E, XMASS, DEDX2)
	13	C.
	14	C. ******************************************************************
	15	C. * *
	16	C. * Calculates energy straggling using Gaussian theory in a step *
	17	C. * *
	18	C. * Input STEP = current step-length (cm) *
	19	C. * Z = Z of the material *
	20	C. * A = A of the material *
	21	C. * RHO = density of the material *
	22	C. * P = momentum of the particle *
	23	C. * E = energy of the particle *
	24	C. * XMASS = mass of the particle *
	25	C. * *
	26	C. * Output DEDX2 = mean square of the straggling in G *
	27	C. * *
	28	C. * ==>Called by : ERTRCH *
	29	C. * Author E.Nagy ********* *
	30	C. * Original routine : GLANDO *
	31	C. * *
	32	C. ******************************************************************
	33	C.
	34	#include "geant321/gconst.inc"
	35	*
	36	IF (STEP.LT.1.E-7) THEN
	37	DEDX2=0.
	38	RETURN
	39	ENDIF
	40	*
	41	* Calculate xi factor (KeV).
	42	BETA = P/E
	43	GAMMA = E/XMASS
	44	XI = (153.5ZSTEPRHO)/(ABETA*BETA)
	45	*
	46	* Maximum energy transfer to atomic electron (KeV).
	47	ETA = BETA*GAMMA
	48	ETASQ = ETA*ETA
	49	RATIO = EMASS/XMASS
	50	F1 = 2.EMASSETASQ
	51	F2 = 1.+2.RATIOGAMMA+RATIO*RATIO
	52	EMAX = 1.E+6*F1/F2
	53	*
	54	*
	55	* * and now sigma2 in GeV
	56	* gaussian
	57	DEDX2 = XIEMAX(1.-(BETABETA/2.))1.E-12
	58	*
	59	END