Bugfix in AliPoints2Memory
[u/mrichter/AliRoot.git] / GEANT321 / gphys / gphys.doc
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fe4da5cc 1*
2* $Id$
3*
4* $Log$
5* Revision 1.1.1.1 1995/10/24 10:21:19 cernlib
6* Geant
7*
8*
9#include "geant321/pilot.h"
10#if defined(CERNLIB_DOC)
11*CMZ : 3.21/02 29/03/94 15.41.21 by S.Giani
12*-- Author :
13*
14************************************************************************
15* *
16* Introduction to the section PHYS *
17* -------------------------------- *
18* *
19* *
20* THE PHYSICS PROCESSES *
21* *
22* The processes currently implemented in GEANT3 can be classified *
23* as follows: *
24* *
25* - Decays in flight *
26* - Multiple scattering (Gaussian or Moliere) *
27* - Continuous electromagnetic processes *
28* - Discrete electromagnetic processes *
29* - Hadronic interactions *
30* - Muon nucleus-interactions. *
31* *
32* The fist two are controlled by the routines GDECAY which *
33* generates the decay products and GMULTS which computes the change *
34* in the angle due to multiple scattering over a given tracking *
35* step. The others are reviewed separately in the following *
36* paragraphs. *
37* For convenience the particles are given a 'tracking type' in *
38* GEANT, depending on their interaction with matter: *
39* *
40* ITRTYP = 1 photon *
41* 2 electron and positron *
42* 3 neutral particles *
43* 4 charged hadrons *
44* 5 muon *
45* 6 'Geantino' *
46* 7 Cerenkov photon *
47* 8 Ion *
48* *
49* The paragraph 5 gives a summary of the physics processes *
50* activated for each type of particle with the momentum range of *
51* validity when relevant. GPHYSI controls the initialisation of the *
52* various processes. *
53* *
54* CONTINUOUS ELECTROMAGNETIC PROCESSES *
55* *
56* GMOLI Initializes Moliere scattering *
57* GPROBI initializes material 'constants' used for computing the *
58* probability of various interactions. *
59* GDRELA Control routine to fill DE/DX tables for energy loss *
60* due to ionisation. *
61* GDRELP Calculates energy loss due to ionisation for charged *
62* particles other than electrons and positrons. *
63* GDRELE Calculates energy loss due to ionisation for electrons *
64* and positrons. As Moller and Bhabba scattering are *
65* treated as discrete processes the energy loss due to *
66* ionisation is a function of the electron kinetic energy *
67* cut-off DCUTE below which these processes are treated as *
68* a continuous energy loss [BASE 030, common /GCPHYS/]. *
69* GBRELA Initializes Bremsstrahlung cross-section and fills *
70* energy loss tables for Bremsstrahlung. Both formulae *
71* depend on the photon energy cut-off BCUTE below which *
72* Bremsstrahlung is treated as a continuous energy loss *
73* [BASE 030, common /GCPHYS/]. *
74* GPRELA Fills DE/DX tables for energy loss by direct pair *
75* production for high energy muons. The corresponding *
76* discrete process is not considered. *
77* GRANGI Calculates the stopping range tables for *
78* electron/positron, muon and proton. *
79* GMULOF Calculates the tables for the maximum step allowed to to *
80* continuous processes: Bending in magnetic field, energy *
81* loss and multiple scattering. *
82* GCOEFF Calculates the interpolation coefficients for the *
83* energy/Range relation to be used in the calculation of *
84* the energy loss. *
85* *
86* DISCRETE ELECTROMAGNETIC PROCESSES *
87* *
88* For the simulation of each given discrete physics process three *
89* tasks have to be performed: *
90* *
91* - The evaluation of the step length. This is computed from the *
92* updated probability for the occurrence of the process. The *
93* corresponding code has been inserted directly in the tracking *
94* routines for each tracking type as appropriate. *
95* - After transport of the particle, the generation of the final *
96* state particles (GEANT routines GPHOT, GCOMP, etc.) *
97* - If the particle survives after the interaction, recompute the *
98* probability. *
99* *
100* It should be outlined that the evaluation of the step length is *
101* made independently for each process which can occur, the final *
102* step size being the minimum of all and the process finally *
103* considered being the corresponding one. *
104* *
105* GPHOTI Tabulates cross-section for photo-electric effect at *
106* initialisation time *
107* GPHOT Simulates photo-electric mechanism *
108* GCOMPI Tabulates cross-section for Compton intersection at *
109* initialisation time *
110* GCOMP Simulates Compton scattering *
111* GPRSGA Tabulates cross-section for pair production at *
112* initialisation time *
113* GPAIRG Simulates electron pair production by photons *
114* GBRSGA Tabulates cross-section for Bremsstrahlung at *
115* initialisation time *
116* GBREME Simulates hard Bremsstrahlung by electrons. - see *
117* cut-off BCUTE in routine GBRELA above *
118* GDRSGA Tabulates cross-section for delta-ray at initialisation *
119* time *
120* GDRAY Simulates delta rays (Moller or Bhabba scattering) - see *
121* cut-off DCUTE in routine GDRELE above *
122* GANNII Tabulates cross-section for positron annihilation at *
123* initialisation time *
124* GANNI Simulates positron annihilation in flight *
125* GANNIR Simulates positron annihilation at rest. *
126* GPFISI Tabulates cross-section for photo-fission *
127* GPFIS Simulates photo-fission *
128* *
129* HADRONIC PROCESSES *
130* *
131* For GHEISHA: *
132* GPGHEI returns the hadronic cross section *
133* GHEISH Simulates hadronic interactions, program GHEISHA (H. *
134* Fesefeldt) in GEANH file. *
135* *
136* For FLUKA: *
137* FLDIST returns the hadronic cross section *
138* FLUFIN Simulates hadronic interactions, program FLUKA *
139* (A.Ferrari et al.) in GEANH file. *
140* *
141* MUON INTERACTION *
142* *
143* GBRELM Tabulates energy loss by soft Bremsstrahlung *
144* GBRSGM Tabulates cross-section for hard Bremsstrahlung *
145* GBREMM Generates hard Bremsstrahlung *
146* GPAIRI Tabulates cross-section for direct pair production *
147* GPAIRM Generate direct pair production *
148* GMUNUI Tabulates cross-section for nuclear interaction *
149* GMUNU Generates nuclear interaction *
150* GDRELM Tabulates energy loss by soft delta rays *
151* GDRSGA Tabulates cross-section for hard delta rays *
152* GDRAY Generates delta rays *
153* *
154************************************************************************
155#endif