[807] | 1 | $Id: README,v 1.21 2005/06/03 13:22:25 flongo Exp $ |
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| 2 | ------------------------------------------------------------------- |
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| 3 | |
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| 4 | ========================================================= |
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| 5 | Geant4 - an Object-Oriented Toolkit for Simulation in HEP |
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| 6 | ========================================================= |
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| 7 | |
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| 8 | gammaray_telescope |
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| 9 | ------------------ |
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| 10 | F.Longo, R.Giannitrapani & G.Santin |
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| 11 | June 2003 |
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| 12 | |
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| 13 | -------------------------------------------------------------- |
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| 14 | Acknowledgments to GEANT4 people, in particular to R.Nartallo, |
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| 15 | A.Pfeiffer, M.G.Pia and G.Cosmo |
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| 16 | -------------------------------------------------------------- |
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| 17 | |
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| 18 | GammaRayTel is an example of application of Geant4 in a space |
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| 19 | envinronment. It simulates a typical telescope for gamma ray analysis; |
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| 20 | the detector setup is composed by a tracker made with silicon planes, |
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| 21 | subdivided in ladders and strips, a CsI calorimeter and an |
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| 22 | anticoincidence system. In this version, the three detectors are made |
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| 23 | sensitive but only the hits on the tracker strips are registered and relevant |
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| 24 | information (energy deposition, position etc) are dumped to an external |
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| 25 | ASCII file for subsequent analysis. If the user has set up the |
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| 26 | AIDA (version 3.0 or compatible) environment or Anaphe/Lizard is available, |
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| 27 | then some histograms with relevant hits information are displayed |
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| 28 | and saved as PostScript files, and histograms and ntuples with |
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| 29 | relevant information are stored on a HBOOK file. |
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| 30 | |
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| 31 | The main features of this example are |
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| 32 | |
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| 33 | a) Macros for the visualization of geometry and tracks with |
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| 34 | OpenGL, VRML and DAWN drivers |
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| 35 | |
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| 36 | b) Implementation of messengers to change some parameters of |
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| 37 | the detector geometry, the particle generator and the analysis |
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| 38 | manager (if present) runtime |
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| 39 | |
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| 40 | c) Readout geometry mechanism to describe an high number of |
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| 41 | subdivisions of the planes of the tracker (strips) without |
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| 42 | affecting in a relevant way the simulation performances |
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| 43 | |
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| 44 | d) Histograming facilities are presently provided for the Linux |
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| 45 | environment either by using the AIDA interfaces, or through |
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| 46 | the Anaphe/Lizard system. |
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| 47 | |
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| 48 | e) User interfaces via Xmotif or normal terminal provided |
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| 49 | |
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| 50 | |
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| 51 | 1. Setting up the environment variables |
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| 52 | --------------------------------------- |
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| 53 | |
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| 54 | - Setup for storing ASCII data |
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| 55 | |
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| 56 | If you want to store the output data in an ASCII file 'Tracks_x.dat' |
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| 57 | where x stays for the run number. You should specify the environment |
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| 58 | variable: |
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| 59 | |
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| 60 | setenv G4STORE_DATA 1 |
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| 61 | |
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| 62 | - Setup for Visualization |
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| 63 | |
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| 64 | IMPORTANT: be sure that your Geant4 installation has been done |
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| 65 | with the proper visualization drivers; for details please see the |
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| 66 | file geant4/source/visualization/README. |
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| 67 | |
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| 68 | To use the visualization drivers set the following variables in |
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| 69 | your local environment: |
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| 70 | |
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| 71 | setenv G4VIS_USE_OPENGLX 1 # OpenGL visualization |
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| 72 | setenv G4VIS_USE_DAWNFILE 1 # DAWN file |
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| 73 | setenv G4VIS_USE_VRMLFILE 1 # VRML file |
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| 74 | setenv G4VRMLFILE_VIEWER vrmlview # If installed |
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| 75 | |
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| 76 | - Setup for Xmotif user interface |
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| 77 | |
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| 78 | setenv G4UI_USE_XM 1 |
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| 79 | |
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| 80 | - Set up for analysis using AIDA3.2.1 and PI1.3.3 |
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| 81 | |
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| 82 | To compile the GammaRayTel example with the analysis tools activated, |
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| 83 | set the following variables |
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| 84 | |
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| 85 | setenv G4ANALYSIS_USE 1 # Use the analysis tools |
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| 86 | |
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| 87 | Users can download the analysis tools from: |
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| 88 | > http://aida.freehep.org/ |
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| 89 | > http://www.cern.ch/PI |
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| 90 | |
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| 91 | 2. Sample run |
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| 92 | ------------- |
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| 93 | |
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| 94 | To run a sample simulation with gamma tracks interacting with |
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| 95 | the detector in its standard configuration and without any |
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| 96 | visualization, execute the following command in the example main |
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| 97 | directory: |
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| 98 | |
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| 99 | $G4WORKDIR/bin/$G4SYSTEM/GammaRayTel |
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| 100 | |
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| 101 | It is possible also to run three different configuration defined in |
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| 102 | macro1.mac, macro2.mac and macro3.mac for visualization (OpenGL, VRML |
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| 103 | and DAWN respectively) with the following command |
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| 104 | |
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| 105 | $G4WORKDIR/bin/$G4SYSTEM/GammaRayTel macroX.mac |
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| 106 | |
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| 107 | where X can be 1, 2 or 3. Be sure to have the right environment (see |
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| 108 | the preceding section) and the proper visualization driver enabled in |
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| 109 | your local G4 installation (see geant4/source/visualization/README for |
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| 110 | more information). |
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| 111 | |
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| 112 | |
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| 113 | 3. Detector description |
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| 114 | ----------------------- |
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| 115 | |
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| 116 | The detector is defined in GammaRayTelDetectorConstruction.cc |
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| 117 | It is composed of a Payload with three main detectors, a Tracker (TKR), a |
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| 118 | Calorimeter (CAL) and an Anticoincidence system (ACD). |
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| 119 | |
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| 120 | The standard configuration is made of a TKR of 15 Layers of 2 views made of |
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| 121 | 4*4 Si single sided silicon detectors with Lead converter, and a CAL of |
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| 122 | 5 layers of CsI, each made of 2 views of 12 CsI bars orthogonally posed. |
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| 123 | 4 lateral panels and a top layer of plastic scintillator (ACL and ACT) |
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| 124 | complete the configuration. |
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| 125 | The Si detectors are composed of two silicon planes subdivided in strips |
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| 126 | aligned along the X axis in one plane and along the Y axis for the other. |
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| 127 | |
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| 128 | The following baseline configuration is adopted: |
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| 129 | |
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| 130 | GEOMETRICAL PARAMETER VALUE |
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| 131 | |
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| 132 | Converter thickness 300 microns |
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| 133 | Silicon Thickness 400 microns |
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| 134 | Silicon Tile Size XY 9 cm |
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| 135 | Silicon Pitch 200.micrometer |
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| 136 | Views Distance 1. mm |
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| 137 | CAL Bar Thickness 1.5 cm |
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| 138 | ACD Thickness 1. cm |
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| 139 | |
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| 140 | It is possible to modify in some way this configuration using the |
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| 141 | commands defined in GammaRayTelDetectorMessenger. |
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| 142 | This feature is available in the UI throught the commands subtree |
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| 143 | "/payload/" (see the help command in the UI for more information). |
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| 144 | |
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| 145 | 4. Physics processes |
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| 146 | -------------------- |
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| 147 | |
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| 148 | This example uses a modular physics list, with a sample of Hadronic processes |
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| 149 | (see the web page http://cmsdoc.cern.ch/~hpw/GHAD/HomePage/ for more adeguate |
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| 150 | physics lists), the Standard or the LowEnergy Electromagnetic processes. |
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| 151 | |
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| 152 | 5. Particle Generator |
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| 153 | --------------------- |
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| 154 | |
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| 155 | The GammaRayTelParticleGenerationAction and its Messenger let the user define |
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| 156 | the incident flux of particles, from a specific direction or from an |
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| 157 | isotropic background. In the first case particles are generated on a spherical |
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| 158 | surface which diameter is perpendicular to the arrival direction. In the second |
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| 159 | case the arrival directions are isotropic. |
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| 160 | |
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| 161 | The user can define also between two spectral options: |
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| 162 | monochromatic or with a power-law dependence. The particle |
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| 163 | generator parameters are accessible throught the UI tree "/gun/" (use the |
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| 164 | UI help for more information). We are planning to include, in the next |
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| 165 | releases of this example, the General Particle Source module of G4. |
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| 166 | |
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| 167 | 6. ReadOutGeometry |
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| 168 | ------------------ |
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| 169 | |
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| 170 | The tracker is made of Silicon Microstrips detectors. The ReadOut geometry |
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| 171 | provides the description of the strips. |
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| 172 | |
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| 173 | 7. Hit |
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| 174 | ------ |
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| 175 | |
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| 176 | In this version the hits from the TKR the CAL and the ACD are generated. |
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| 177 | Only the hit from the TRK are saved. Each TKR hit contains the following |
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| 178 | information |
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| 179 | |
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| 180 | a) ID of the event (this is important for multiple events run) |
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| 181 | b) Energy deposition of the particle in the strip (keV) |
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| 182 | c) Number of the strip |
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| 183 | d) Number of the plane |
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| 184 | e) Type of the plane (1=X 0=Y) |
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| 185 | f) Position of the hit (x,y,z) in the reference frame of the payload |
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| 186 | |
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| 187 | The hit information are saved on an ASCII file named Tracks_N.dat, where |
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| 188 | N is the progressive ID number associated to the run. |
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| 189 | |
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| 190 | 8. Analysis |
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| 191 | ---------------- |
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| 192 | |
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| 193 | The analysis part of GammaRayTel is based on the AIDA interfaces and their |
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| 194 | implementation in Anaphe; please look at their documentation for more details. |
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| 195 | Keep in mind that the actual implementation of the analysis tools in GammaRayTel |
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| 196 | is of a pedagogical nature, so we kept it as simple as possible. |
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| 197 | |
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| 198 | The actual analysis produces some histograms (see next section) and an ntuple. |
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| 199 | Both the histograms and the ntuple are saved at the end of the run in the file |
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| 200 | "gammaraytel.hbook". You can than analyze offline the contents of such a file; |
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| 201 | the GammaRayTel contains also a very simple python script that can be used with |
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| 202 | Lizard to plot the histograms See the Lizard documentation on how to access |
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| 203 | the ntuple. |
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| 204 | Please note that in a multiple run session, the last run always override the |
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| 205 | hbook file. |
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| 206 | |
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| 207 | 9. Histogramming |
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| 208 | ---------------- |
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| 209 | |
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| 210 | Some hits information can be visualized runtime using the Anaphe Plotter |
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| 211 | (if it is available on the user platform); two 1D histograms can be |
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| 212 | visualized during the simulation run. |
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| 213 | |
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| 214 | The 1D histograms contain the energy deposition in the last X plane of |
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| 215 | the TKR and the hits distribution along the X planes of the TKR |
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| 216 | (note again that these histograms have been chosen more for pedagogical |
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| 217 | motivation than for physical one). |
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| 218 | |
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| 219 | These histograms are filled and updated at every event and are initialized |
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| 220 | with each new run; the scale of the histograms is automatically derived from |
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| 221 | the detector geometry. |
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| 222 | |
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| 223 | Throught a messenger it is possible to set some options with |
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| 224 | the UI subtree "/analysis/" (use the UI help for more info); |
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| 225 | If you feel that the simulation is too slow with the |
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| 226 | histograms updated every event, you can disable the drawing and retain |
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| 227 | the saving. Please note that the updating of the histograms is triggered |
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| 228 | only when there is some hit in an event. |
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| 229 | |
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| 230 | In this example we only show the use of very basic feature of this new |
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| 231 | simulation/analysis framework. |
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| 232 | |
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| 233 | 10. Digi |
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| 234 | -------- |
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| 235 | |
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| 236 | For the TKR also the digits corresponding to the Hits are generated. |
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| 237 | A digi is generated when the hit energy deposit is greater than a threshold |
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| 238 | (in this example setted at 120 keV). |
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| 239 | The TKR digi information are stored on the same file Tracks_N.dat and contain: |
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| 240 | |
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| 241 | a) ID of the event (this is important for multiple events run) |
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| 242 | b) Number of the strip |
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| 243 | c) Number of the plane |
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| 244 | d) Type of the plane (1=X 0=Y) |
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| 245 | |
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| 246 | 11. Classes Overview |
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| 247 | ------------------- |
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| 248 | |
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| 249 | This is the overview of the classes defined in this example |
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| 250 | |
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| 251 | GammaRayTelPrimaryGeneratorAction |
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| 252 | User action for primaries generator |
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| 253 | |
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| 254 | GammaRayTelPrimaryGeneratorMessenger |
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| 255 | Messenger for interactive particle generator |
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| 256 | parameters modification via the User Interface |
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| 257 | |
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| 258 | GammaRayTelPhysicsList |
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| 259 | Determination of modular physics classes |
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| 260 | |
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| 261 | GammaRayTelGeneralPhysics |
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| 262 | Decay processes |
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| 263 | |
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| 264 | GammaRayTelEMPhysics |
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| 265 | Std and LowE physics processes (for gamma & e-/e+) |
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| 266 | |
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| 267 | GammaRayTelMuonPhysics |
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| 268 | Muon & its processes |
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| 269 | |
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| 270 | GammaRayTelIonPhysics |
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| 271 | Ions and their processes |
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| 272 | |
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| 273 | GammaRayTelHadronPhysics |
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| 274 | Sample of hadronic processes |
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| 275 | |
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| 276 | GammaRayTelTelVisManager |
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| 277 | Visualization manager class |
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| 278 | |
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| 279 | GammaRayTelDetectorConstruction |
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| 280 | Geometry and material definitions for the detector |
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| 281 | |
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| 282 | GammaRayTelDetectorMessenger |
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| 283 | Messenger for interactive geometry parameters |
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| 284 | modification via the User Interface |
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| 285 | |
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| 286 | GammaRayTelAnalysis |
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| 287 | Analysis manager class with Lizard tool (experimental) |
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| 288 | |
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| 289 | GammaRayTelAnalysisMessenger |
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| 290 | Messenger for interactive analysis options modification |
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| 291 | via the User Interface |
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| 292 | |
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| 293 | GammaRayTelRunAction |
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| 294 | User run action class |
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| 295 | |
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| 296 | GammaRayTelEventAction |
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| 297 | User event action class |
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| 298 | |
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| 299 | GammaRayTelTrackerHit |
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| 300 | Description of the hits on the tracker |
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| 301 | |
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| 302 | GammaRayTelDigi |
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| 303 | Description of the digi on the tracker |
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| 304 | |
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| 305 | GammaRayTelDigitizer |
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| 306 | Description of the digitizer for the tracker |
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| 307 | |
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| 308 | GammaRayTelTrackerROGeometry |
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| 309 | Description of the readout geometry for strips subdivision |
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| 310 | |
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| 311 | GammaRayTelTrackerSD |
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| 312 | Description of the TKR sensitive detector |
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| 313 | |
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| 314 | GammaRayTelAnticoincidenceHit |
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| 315 | Description of the hits on the anticoincidence |
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| 316 | |
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| 317 | GammaRayTelAnticoincidenceSD |
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| 318 | Description of the ACD sensitive detector |
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| 319 | |
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| 320 | GammaRayTelCalorimeterHit |
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| 321 | Description of the hits on the calorimeter |
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| 322 | |
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| 323 | GammaRayTelCalorimeterSD |
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| 324 | Description of the CAL sensitive detector |
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| 326 | |
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| 327 | |
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| 328 | |
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| 329 | |
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| 330 | |
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| 331 | |
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| 332 | |
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| 333 | |
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| 334 | |
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