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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) | |
13 | C. | |
14 | C. ****************************************************************** | |
15 | C. * * | |
16 | C. * Calculates the mean 1/DENS*dE/dx of an ion with charge Z1, * | |
17 | C. * atomic weight A1 and kinetic energy T in an element * | |
18 | C. * of atomic number Z2, atomic weight A2 and density * | |
19 | C. * DENS ( the density is just used for the calculation * | |
20 | C. * of the density effect in the case of high T ). * | |
21 | C. * The routine reproduces the experimental and/or tabulated * | |
22 | C. * mean energy losses reasonably well. * | |
23 | C. * * | |
24 | C. * The mean stopping power is obtained by calculating the proton * | |
25 | C. * energy loss S at the equivalent proton kinetic energy and * | |
26 | C. * multiplying this value by the effective charge of the ion. * | |
27 | C. * This method is used for high T ( T/A1 > Tamax , where * | |
28 | C. * Tamax depend on Z1 and Z2 , Tamax .le. few MeV). * | |
29 | C. * In the case of low T , the energy loss curve has been * | |
30 | C. * extrapolated down to T -> 0. * | |
31 | C. * * | |
32 | C. * ==>Called by : GDRELA * | |
33 | C. * Author L.Urban ********* * | |
34 | C. * * | |
35 | C. ****************************************************************** | |
36 | C. | |
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 |