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0001 \page ExampleHadr03 Example Hadr03
0002
0003 - How to compute total cross section from the direct evaluation of the
0004 mean free path ( see below, item Physics).
0005 - How to identify nuclear reactions.
0006 - How to plot energy spectrum of secondary particles.
0007
0008 ## GEOMETRY DEFINITION
0009
0010 It is a single box representing a 'semi infinite' homogeneous medium.
0011 Two parameters define the geometry :
0012 - the material of the box,
0013 - the (full) size of the box.
0014
0015 The default geometry (10 m of molybdenum) is built in DetectorConstruction,
0016 but the above parameters can be changed interactively via commands defined
0017 in DetectorMessenger.
0018
0019 ## PHYSICS LIST
0020
0021 The PhysicsList contains builders for hadronic interactions.
0022 Predefined G4 PhysicsConstructors or 'local' PhysicsConstructors can be used
0023 (see geant4/source/physics_lists or example runAndEvent/RE04).
0024
0025 In order not to introduce 'artificial' constraints on the step size,
0026 electromagnetic processes are not registered: there is no continuous energy
0027 loss.
0028
0029 Several hadronic physics options are controlled by environment variables.
0030 To select them, see Hadr03.cc
0031
0032 ## AN EVENT : THE PRIMARY GENERATOR
0033
0034 The primary kinematic consists of a single particle starting at the edge
0035 of the box. The type of the particle and its energy are set in
0036 PrimaryGeneratorAction (neutron 1 MeV), and can be changed via the G4
0037 build-in commands of ParticleGun class (see the macros provided with
0038 this example).
0039
0040 ## PHYSICS
0041
0042 An event is killed at the first interaction of the incident particle.
0043 The absorption length, also called mean free path, is computed as
0044 the mean value of the track length of the incident particle.
0045 This is why the medium must be 'infinite' : to be sure that interaction
0046 occurs at any events.
0047
0048 The result is compared with the 'input' value, i.e. with the cross sections
0049 given by G4HadronicProcessStore and used by Geant4.
0050
0051 The list of nuclear reactions that occured is printed.
0052 (the number of gamma of deexcitation is not printed).
0053
0054 Then, comes the total list of generated particles and ions.
0055 The energy spectrum of the scattered particle (if any) and of the created
0056 secondaries are plotted (see SteppingAction).
0057
0058 Momentum conservation is checked as :
0059 ```
0060 momentum balance = modulus(P_out - P_in)
0061 ```
0062
0063 A set of macros defining various run conditions are provided.
0064 The processes can be actived/inactived in order to survey the processes
0065 individually.
0066
0067 ## HISTOGRAMS
0068
0069 The test contains 13 built-in 1D histograms, which are managed by
0070 G4AnalysisManager and its Messenger. The histos can be individually
0071 activated with the command :
0072 /analysis/h1/set id nbBins valMin valMax unit
0073 where unit is the desired unit for the histo (MeV or keV, etc..)
0074 (see the macros xxxx.mac).
0075 ```
0076 1 "kinetic energy of scattered primary particle"
0077 2 "kinetic energy of gamma"
0078 3 "kinetic energy of e-"
0079 4 "kinetic energy of neutrons"
0080 5 "kinetic energy of protons"
0081 6 "kinetic energy of deuterons"
0082 7 "kinetic energy of alphas"
0083 8 "kinetic energy of nuclei"
0084 9 "kinetic energy of mesons"
0085 10 "kinetic energy of baryons"
0086 11 "Q = Ekin out - Ekin in"
0087 12 "Pbalance = mag(P_out - P_in)"
0088 13 "atomic mass of nuclei"
0089 ```
0090 The histograms are managed by the HistoManager class and its Messenger.
0091 The histos can be individually activated with the command :
0092 ```
0093 /analysis/h1/set id nbBins valMin valMax unit
0094 ```
0095 where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
0096
0097 One can control the name of the histograms file with the command:
0098 ```
0099 /analysis/setFileName name (default Hadr03)
0100 ```
0101
0102 It is possible to choose the format of the histogram file : root (default),
0103 xml, csv, by using namespace in HistoManager.hh
0104
0105 It is also possible to print selected histograms on an ascii file:
0106 ```
0107 /analysis/h1/setAscii id
0108 ```
0109 All selected histos will be written on a file name.ascii (default Hadr03)
0110
0111 ## VISUALIZATION
0112
0113 The Visualization Manager is set in the main().
0114 The initialisation of the drawing is done via the commands
0115 /vis/... in the macro vis.mac. To get visualisation:
0116 ```
0117 > /control/execute vis.mac
0118 ```
0119
0120 The detector has a default view which is a longitudinal view of the box.
0121 The tracks are drawn at the end of event, and erased at the end of run.
0122
0123 ## HOW TO START ?
0124
0125 Execute Hadr03 in 'batch' mode from macro files :
0126 ```
0127 % ./Hadr03 inelastic.mac
0128 ```
0129
0130 Execute Hadr03 in 'interactive mode' with visualization :
0131 ```
0132 % ./Hadr03
0133 Idle> control/execute vis.mac
0134 ....
0135 Idle> type your commands
0136 ....
0137 Idle> exit
0138 ```
0139
0140 Macros provided in this example:
0141 - hadr03.in: macro used in Geant4 testing
0142 - Au196.mac: neutron (1 MeV) on Au195
0143 - elastic.mac: proton (10 MeV) on Mo100. Elastic collisions alone
0144 - fusion.mac: deuteron (400 keV) on tritium
0145 - gamma.mac: gamma (10 MeV) on Au196
0146 - inelastic.mac: proton (10 MaV) on Mo98. Inelastic interactions alone
0147 - ion.mac: Li7 (140 MeV) on Be9
0148 - nCapture.mac: neutron (1 eV) on Boron. Capture process alone
0149 - nFission.mac: neutron (1 eV) on U235. Fission process alone
0150 - neutron.mac: neutron (1 MeV) on Boron
0151
0152 Macros to be run interactively:
0153 - debug.mac: proton (10 MeV) on Boron
0154 - vis.mac: To activate visualization
