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Commit | Line | Data |
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fe4da5cc | 1 | * |
2 | * $Id$ | |
3 | * | |
4 | * $Log$ | |
5 | * Revision 1.1.1.1 1995/10/24 10:21:33 cernlib | |
6 | * Geant | |
7 | * | |
8 | * | |
9 | #include "geant321/pilot.h" | |
10 | *CMZ : 3.21/04 24/02/95 14.49.53 by S.Giani | |
11 | *-- Author : | |
12 | FUNCTION GPRSGG(Z,E) | |
13 | C. | |
14 | C. ****************************************************************** | |
15 | C. * * | |
16 | C. * To calculate cross-section for e+e- production * | |
17 | C. * by photons (in barn/atom) * | |
18 | C. * * | |
19 | C. * ==>Called by : GPRSGA * | |
20 | C. * Author L.Urban ********* * | |
21 | C. * Modified by: G.Battistoni * | |
22 | C. * * | |
23 | C. * constant cross section is assumed above 100 GeV ! * | |
24 | C. ****************************************************************** | |
25 | C. | |
26 | #include "geant321/gconsp.inc" | |
27 | DIMENSION C(18),CC(3) | |
28 | DATA C/ 0.87842E-3,-0.19625E-2, 0.12949E-2,-0.20028E-3 | |
29 | + , 0.12575E-4,-0.28333E-6,-0.10342E-4, 0.17692E-4 | |
30 | + ,-0.82391E-5, 0.13063E-5,-0.90815E-7, 0.23586E-8 | |
31 | + ,-0.45263E-3, 0.11161E-2,-0.86749E-3, 0.21773E-3 | |
32 | + ,-0.20467E-4, 0.65372E-6/ | |
33 | DATA EUPP/100./ | |
34 | C. | |
35 | C. ------------------------------------------------------------------ | |
36 | C. | |
37 | SIG=0. | |
38 | * | |
39 | ESAV=E | |
40 | IF(E.GT.EUPP) E=EUPP | |
41 | * | |
42 | IF(E.LE.2.*EMASS)GO TO 90 | |
43 | X=LOG(E/EMASS) | |
44 | DO 20 I=1,3 | |
45 | CC(I)=0. | |
46 | D=1. | |
47 | DO 10 J=1,6 | |
48 | JJ=6*I+J-6 | |
49 | CC(I)=CC(I)+D*C(JJ) | |
50 | D=D*X | |
51 | 10 CONTINUE | |
52 | 20 CONTINUE | |
53 | C | |
54 | SIG=Z*(Z+1.)*(CC(1)+CC(2)*Z+CC(3)/Z) | |
55 | C | |
56 | 90 IF(SIG.LT.0.)SIG=0. | |
57 | GPRSGG=SIG | |
58 | * | |
59 | E=ESAV | |
60 | * | |
61 | END |