[1199] | 1 | $Id: README,v 1.2 2001/11/28 09:39:39 elena Exp $ |
---|
| 2 | ------------------------------------------------------------------- |
---|
| 3 | |
---|
| 4 | ========================================================= |
---|
| 5 | Geant4 - an Object-Oriented Toolkit for Simulation in HEP |
---|
| 6 | ========================================================= |
---|
| 7 | |
---|
| 8 | xray_fluorescence |
---|
| 9 | -------------- |
---|
| 10 | XrayFluo is an advanced Geant4 example based on a realistic simulation of |
---|
| 11 | a test beam. |
---|
| 12 | The aim of the test beam was to characterize the response function of an |
---|
| 13 | HPGe detector used to measure fluorescence emissions from samples composed |
---|
| 14 | of different materials irradiated with a monochromatic beam of photons. |
---|
| 15 | In this example the geometry of the detector is simplified: |
---|
| 16 | one single pixel is used instead of an array of pixels. |
---|
| 17 | The response function is tabulated for ten different values of incident |
---|
| 18 | energy and stored in the file response.dat. |
---|
| 19 | The sample, a simple box whose material can be selected, can be irradiated |
---|
| 20 | with different particles, with different spectra for the incident energy and |
---|
| 21 | with different shapes of the primary generator. |
---|
| 22 | A part from the sample and the detector there are two diaphragm reproducing |
---|
| 23 | those used to collimate the incident beam during the test beam. |
---|
| 24 | |
---|
| 25 | The aim of this advanced example is to illustrate the use of particle |
---|
| 26 | generation and analysis schemes available in Geant4: |
---|
| 27 | |
---|
| 28 | - the generation of particles is done via the G4ParticleGun: the example |
---|
| 29 | shows how to use it in order to obtain a beam of circular section or |
---|
| 30 | a particle source isotropic in space |
---|
| 31 | |
---|
| 32 | _ the example includes the possibility to shoot particles according to a |
---|
| 33 | given energy spectrum: the files B_flare.dat, C_Flare.dat and M_flare.dat |
---|
| 34 | store the spectra of photons during solar flares, the files |
---|
| 35 | mercury2_flx_solmax.dat and mercury_flx_solmin.dat contain the spectra of |
---|
| 36 | protons respectively during solar maximum and solar minimumconditions, and |
---|
| 37 | merc2_flx_alp_max.dat merc_flx_alp_min.dat contain the spectra of alpha |
---|
| 38 | particles again respectively during solar maximum and solar minimum |
---|
| 39 | conditions. |
---|
| 40 | |
---|
| 41 | - histograming facilities are provided for the Linux environment only |
---|
| 42 | with the Lizard system. |
---|
| 43 | |
---|
| 44 | |
---|
| 45 | In order to be able to use any of these packages, prior installation is |
---|
| 46 | necessary and a number of environment variables will have to be set. |
---|
| 47 | |
---|
| 48 | |
---|
| 49 | #set up VRMLview |
---|
| 50 | setenv G4VIS_BUILD_VRMLFILE_DRIVER 1 |
---|
| 51 | setenv G4VIS_USE_VRML 1 |
---|
| 52 | setenv G4VIS_USE_VRMLFILE 1 |
---|
| 53 | setenv G4VRMLFILE_MAX_FILE_NUM 100 |
---|
| 54 | setenv G4VRMLFILE_VIEWER vrmlview #if installed |
---|
| 55 | setenv G4VIS_USE_VRML 1 |
---|
| 56 | setenv G4VIS_USE_VRMLFILE 1 |
---|
| 57 | setenv PATH ${PATH}:"/afs/cern.ch/sw/contrib/VRML/bin/Linux" |
---|
| 58 | |
---|
| 59 | #set up OpenGL or Mesa |
---|
| 60 | setenv G4VIS_BUILD_OPENGLX_DRIVER 1 |
---|
| 61 | setenv G4VIS_USE_OPENGLX 1 |
---|
| 62 | setenv OGLHOME /afs/cern.ch/sw/geant4/dev/Mesa/Linux-g++ |
---|
| 63 | |
---|
| 64 | #set up DAWN |
---|
| 65 | setenv G4VIS_BUILD_DAWN_DRIVER 1 |
---|
| 66 | setenv G4VIS_BUILD_DAWNFILE_DRIVER 1 |
---|
| 67 | setenv G4VIS_USE_DAWN 1 |
---|
| 68 | setenv G4VIS_USE_DAWNFILE 1 |
---|
| 69 | setenv PATH ${PATH}:"/afs/cern.ch/sw/geant4/dev/DAWN/Linux-g++" |
---|
| 70 | |
---|
| 71 | #set up Lizard and Anaphe |
---|
| 72 | |
---|
| 73 | setenv LHCXX_REL_DIR /afs/cern.ch/sw/lhcxx/specific/redhat61/egcs_1.1.2/3.6.4-sec |
---|
| 74 | setenv PATH ${PATH}:${LHCXX_REL_DIR}/bin |
---|
| 75 | source /afs/cern.ch/sw/lhcxx/share/LHCXX/3.6.4-sec/install/sharedstart.csh |
---|
| 76 | |
---|
| 77 | setenv G4ANALYSIS_USE 1 |
---|
| 78 | (this flag is required if you want to compile and run the example with the |
---|
| 79 | analysis facilities) |
---|
| 80 | |
---|
| 81 | #path to the lowEnergy data base |
---|
| 82 | |
---|
| 83 | setenv G4LEDATA /afs/cern.ch/sw/geant4/stt/dev1/src/G4EMLOW0.4 |
---|
| 84 | |
---|
| 85 | 1. Run |
---|
| 86 | To execute a sample simulation with visualisation of tracks |
---|
| 87 | reaching the detector run: |
---|
| 88 | |
---|
| 89 | XrayFluo |
---|
| 90 | |
---|
| 91 | execute command "/control/execute xxxxx.mac" |
---|
| 92 | |
---|
| 93 | |
---|
| 94 | If the Lizard analysis options are set, histograming windows will |
---|
| 95 | automatically stored in the corresponding files |
---|
| 96 | |
---|
| 97 | 2. Detector description |
---|
| 98 | |
---|
| 99 | The telescope and detector geometry is defined in |
---|
| 100 | XrayFluoDetectorConstruction.cc |
---|
| 101 | |
---|
| 102 | 3. Physics processes |
---|
| 103 | |
---|
| 104 | The physics processes are in XrayFluoPhysicsList.cc |
---|
| 105 | The main process in this example is fluorescence emission from the sample. |
---|
| 106 | |
---|
| 107 | 4. Event generation |
---|
| 108 | |
---|
| 109 | This is done using the G4ParticleGun with some modifications. See |
---|
| 110 | XrayFluoParticleGeneratorAction.cc |
---|
| 111 | |
---|
| 112 | 5. Analysis |
---|
| 113 | |
---|
| 114 | At present the analysis package implemented is Lizard. As this is still |
---|
| 115 | under development only simple histograming and a dummy ntuple are used. |
---|
| 116 | |
---|
| 117 | Lizard is not currently implemented on platforms other than Linux. |
---|
| 118 | To build and execute the example on other platforms the analysis |
---|
| 119 | environment variables must not be set. |
---|
| 120 | |
---|
| 121 | The example provides also two Phyton files used to display and fit the |
---|
| 122 | histograms. |
---|
| 123 | |
---|
| 124 | |
---|
| 125 | |
---|
| 126 | |
---|
| 127 | |
---|