Bugfix in AliPoints2Memory
[u/mrichter/AliRoot.git] / GEANT321 / gphys / gdreli.F
CommitLineData
fe4da5cc 1*
2* $Id$
3*
4* $Log$
5* Revision 1.1.1.1 1995/10/24 10:21:24 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 GDRELI(A1,Z1,A2,Z2,DENS,T,DEDX)
13C.
14C. ******************************************************************
15C. * *
16C. * Calculates the mean 1/DENS*dE/dx of an ion with charge Z1, *
17C. * atomic weight A1 and kinetic energy T in an element *
18C. * of atomic number Z2, atomic weight A2 and density *
19C. * DENS ( the density is just used for the calculation *
20C. * of the density effect in the case of high T ). *
21C. * The routine reproduces the experimental and/or tabulated *
22C. * mean energy losses reasonably well. *
23C. * *
24C. * The mean stopping power is obtained by calculating the proton *
25C. * energy loss S at the equivalent proton kinetic energy and *
26C. * multiplying this value by the effective charge of the ion. *
27C. * This method is used for high T ( T/A1 > Tamax , where *
28C. * Tamax depend on Z1 and Z2 , Tamax .le. few MeV). *
29C. * In the case of low T , the energy loss curve has been *
30C. * extrapolated down to T -> 0. *
31C. * *
32C. * ==>Called by : GDRELA *
33C. * Author L.Urban ********* *
34C. * *
35C. ******************************************************************
36C.
37#include "geant321/gconsp.inc"
38#include "geant321/gccuts.inc"
39#include "geant321/gcunit.inc"
40 PARAMETER (AMU=0.93149432,D=0.00015357)
41*
42 EM=A1*AMU
43 TA=PMASS*T/EM
44*
45 Z11=Z1*Z1
46 TAMAX=(120.902-3.121*Z1+0.270*Z11)-(35.988-27.794*Z1+0.120*Z11)*
47 + LOG(Z2)
48 TAMAX=0.000001*TAMAX
49*
50* calculate stopping power (total loss) , save DCUTM before
51*
52 CUTSAV=DCUTM
53 DCUTM=BIG
54*
55 IF(TA.GE.TAMAX) THEN
56*
57* "high energy" case
58*
59 CALL GDRELP(A2,Z2,DENS,TA,S)
60 S=Z1**2*GEFCH2(Z1,Z2,TA)*S
61 ELSE
62*
63* "low energy" case
64*
65 CALL GDRELP(A2,Z2,DENS,TAMAX,S0)
66 S0=Z1**2*GEFCH2(Z1,Z2,TAMAX)*S0
67 R=TA/TAMAX
68 S=S0*(2.*SQRT(R)-R)
69 ENDIF
70*
71 DCUTM=CUTSAV
72 TMAX=2.*EMASS*T*(T+2.*EM)/EM**2
73*
74* check whether restricted loss needed ?
75* if restricted loss , calculate the loss from delta rays
76*
77 IF(DCUTM.LT.TMAX) THEN
78 BET2=T*(T+2.*EM)/(T+EM)**2
79 R=DCUTM/TMAX
80 DELTA=-LOG(R)-BET2*(1.-R)
81 DELTA=D*Z2*Z1**2*DELTA/(A2*BET2)
82 S=S-DELTA
83 IF(S.LT.0.) S=0.
84 ENDIF
85*
86 DEDX=S
87*
88 END