| 1 | $Id: README,v 1.4 2007/11/13 14:13:31 maire Exp $ |
|---|
| 2 | ------------------------------------------------------------------- |
|---|
| 3 | |
|---|
| 4 | ========================================================= |
|---|
| 5 | Geant4 - an Object-Oriented Toolkit for Simulation in HEP |
|---|
| 6 | ========================================================= |
|---|
| 7 | |
|---|
| 8 | TestEm15 |
|---|
| 9 | -------- |
|---|
| 10 | |
|---|
| 11 | How to compute and plot the final state of Multiple Scattering |
|---|
| 12 | considered as an isolated process. |
|---|
| 13 | The method is exposed below : see item Physics. |
|---|
| 14 | |
|---|
| 15 | 1- GEOMETRY DEFINITION |
|---|
| 16 | |
|---|
| 17 | It is a single box representing a 'semi infinite' homogeneous medium. |
|---|
| 18 | Two parameters define the geometry : |
|---|
| 19 | - the material of the box, |
|---|
| 20 | - the (full) size of the box. |
|---|
| 21 | |
|---|
| 22 | The default geometry (100 m of water) is constructed in |
|---|
| 23 | DetectorConstruction, but the above parameters can be changed |
|---|
| 24 | interactively via the commands defined in DetectorMessenger. |
|---|
| 25 | |
|---|
| 26 | 2- PHYSICS LIST |
|---|
| 27 | |
|---|
| 28 | The physics list contains the standard electromagnetic processes. |
|---|
| 29 | In order not to introduce 'articicial' constraints on the step size, |
|---|
| 30 | there is no limitation from the maximum energy lost per step. |
|---|
| 31 | |
|---|
| 32 | 3- AN EVENT : THE PRIMARY GENERATOR |
|---|
| 33 | |
|---|
| 34 | The primary kinematic consists of a single particle starting at the edge |
|---|
| 35 | of the box. The type of the particle and its energy are set in |
|---|
| 36 | PrimaryGeneratorAction (1 MeV electron), and can be changed via the G4 |
|---|
| 37 | build-in commands of ParticleGun class (see the macros provided with |
|---|
| 38 | this example). |
|---|
| 39 | |
|---|
| 40 | 4- PHYSICS |
|---|
| 41 | |
|---|
| 42 | All discrete processes are inactivated (see provided macros), |
|---|
| 43 | so that Multiple Scattering is 'forced' to determine the first step of |
|---|
| 44 | the primary particle. The step size and the final state are computed |
|---|
| 45 | and plotted. Then the event is immediately killed. |
|---|
| 46 | |
|---|
| 47 | The result is compared with the 'input' data, i.e. with the cross |
|---|
| 48 | sections stored in the PhysicsTables and used by Geant4. |
|---|
| 49 | |
|---|
| 50 | The stepMax command provides an additionnal control of the step size of |
|---|
| 51 | the multiple scattering. |
|---|
| 52 | |
|---|
| 53 | |
|---|
| 54 | 5- HISTOGRAMS |
|---|
| 55 | |
|---|
| 56 | The test contains 9 built-in 1D histograms, which are managed by the |
|---|
| 57 | HistoManager class and its Messenger. The histos can be individually |
|---|
| 58 | activated with the command : |
|---|
| 59 | /testem/histo/setHisto id nbBins valMin valMax unit |
|---|
| 60 | where unit is the desired unit for the histo (MeV or keV, etc..) |
|---|
| 61 | (see the macros xxxx.mac). |
|---|
| 62 | |
|---|
| 63 | 1 Multiple Scattering. True step length |
|---|
| 64 | 2 Multiple Scattering. Geom step length |
|---|
| 65 | 3 Multiple Scattering. Ratio geomSl/trueSl |
|---|
| 66 | 4 Multiple Scattering. Lateral displacement: radius |
|---|
| 67 | 5 Multiple Scattering. Lateral displac: psi_space |
|---|
| 68 | 6 Multiple Scattering. Angular distrib: theta_plane |
|---|
| 69 | 7 Multiple Scattering. Phi-position angle |
|---|
| 70 | 8 Multiple Scattering. Phi-direction angle |
|---|
| 71 | 9 Multiple Scattering. Correlation: cos(phiPos-phiDir) |
|---|
| 72 | |
|---|
| 73 | See below the note on histogram tools. |
|---|
| 74 | |
|---|
| 75 | One can control the name and the type of the histograms file with |
|---|
| 76 | the commands: |
|---|
| 77 | /testem/histo/setFileName name (default testem15) |
|---|
| 78 | /testem/histo/setFileType name (default hbook) |
|---|
| 79 | |
|---|
| 80 | It is also possible to print selected histograms on an ascii file: |
|---|
| 81 | /testem/histo/printHisto id |
|---|
| 82 | All selected histos will be written on a file name.ascii |
|---|
| 83 | (default testem15) |
|---|
| 84 | |
|---|
| 85 | Note that, by default, histograms are disabled. To activate them, |
|---|
| 86 | uncomment the flag G4ANALYSIS_USE in GNUmakefile. |
|---|
| 87 | |
|---|
| 88 | 6- VISUALIZATION |
|---|
| 89 | |
|---|
| 90 | The Visualization Manager is set in the main(). |
|---|
| 91 | The initialisation of the drawing is done via the commands |
|---|
| 92 | /vis/... in the macro vis.mac. To get visualisation: |
|---|
| 93 | > /control/execute vis.mac |
|---|
| 94 | |
|---|
| 95 | The detector has a default view which is a longitudinal view of the |
|---|
| 96 | box. |
|---|
| 97 | |
|---|
| 98 | The tracks are drawn at the end of event, and erased at the end of run. |
|---|
| 99 | |
|---|
| 100 | 7- HOW TO START ? |
|---|
| 101 | |
|---|
| 102 | compile and link to generate an executable |
|---|
| 103 | % cd geant4/examples/extended/electromagnetic/TestEm15 |
|---|
| 104 | % gmake |
|---|
| 105 | |
|---|
| 106 | execute TestEm15 in 'batch' mode from macro files : |
|---|
| 107 | % TestEm15 compt.mac |
|---|
| 108 | |
|---|
| 109 | execute TestEm15 in 'interactive mode' with visualization : |
|---|
| 110 | % TestEm15 |
|---|
| 111 | Idle> control/execute vis.mac |
|---|
| 112 | .... |
|---|
| 113 | Idle> type your commands |
|---|
| 114 | .... |
|---|
| 115 | Idle> exit |
|---|
| 116 | |
|---|
| 117 | |
|---|
| 118 | 8- USING HISTOGRAMS |
|---|
| 119 | |
|---|
| 120 | By default the histograms are not activated. To activate histograms |
|---|
| 121 | the environment variable G4ANALYSIS_USE should be defined. For instance |
|---|
| 122 | uncomment the flag G4ANALYSIS_USE in GNUmakefile. |
|---|
| 123 | |
|---|
| 124 | Before compilation of the example it is optimal to clean up old files: |
|---|
| 125 | gmake histclean |
|---|
| 126 | gmake |
|---|
| 127 | |
|---|
| 128 | To use histograms, at least one of the AIDA implementations should be |
|---|
| 129 | available (see http://aida.freehep.org). |
|---|
| 130 | |
|---|
| 131 | 8a - PI |
|---|
| 132 | |
|---|
| 133 | A package including AIDA and extended interfaces also using Python is PI, |
|---|
| 134 | available from: http://cern.ch/pi |
|---|
| 135 | |
|---|
| 136 | Once installed PI or PI-Lite in a specified local area $MYPY, it is required |
|---|
| 137 | to add the installation path to $PATH, i.e. for example, for release 1.2.1 of |
|---|
| 138 | PI: |
|---|
| 139 | setenv PATH ${PATH}:$MYPI/1.2.1/app/releases/PI/PI_1_2_1/rh73_gcc32/bin |
|---|
| 140 | |
|---|
| 141 | CERN users can use the PATH to the LCG area on AFS. |
|---|
| 142 | Before running the example the command should be issued: |
|---|
| 143 | eval `aida-config --runtime csh` |
|---|
| 144 | |
|---|
| 145 | 8b - OpenScientist |
|---|
| 146 | |
|---|
| 147 | OpenScientist is available at http://OpenScientist.lal.in2p3.fr. |
|---|
| 148 | |
|---|
| 149 | You have to "setup" the OpenScientist AIDA implementation before compiling |
|---|
| 150 | (then with G4ANALYSIS_USE set) and running your Geant4 application. |
|---|
| 151 | |
|---|
| 152 | On UNIX you setup, with a csh flavoured shell : |
|---|
| 153 | csh> source <<OpenScientist install path>/aida-setup.csh |
|---|
| 154 | or with a sh flavoured shell : |
|---|
| 155 | sh> . <<OpenScientist install path>/aida-setup.sh |
|---|
| 156 | On Windows : |
|---|
| 157 | DOS> call <<OpenScientist install path>/aida-setup.bat |
|---|
| 158 | |
|---|
| 159 | You can use various file formats for writing (AIDA-XML, hbook, root). |
|---|
| 160 | These formats are readable by the Lab onx interactive program |
|---|
| 161 | or the OpenPAW application. See the web pages. |
|---|
| 162 | |
|---|
| 163 | |
|---|
| 164 | With OpenPAW, on a run.hbook file, one can view the histograms |
|---|
| 165 | with something like : |
|---|
| 166 | OS> opaw |
|---|
| 167 | opaw> h/file 1 run.hbook ( or opaw> h/file 1 run.aida or run.root) |
|---|
| 168 | opaw> zone 2 2 |
|---|
| 169 | opaw> h/plot 1 |
|---|
| 170 | opaw> h/plot 2 |
|---|
