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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 |