| 1 | $Id: README,v 1.5 2010/09/08 11:22:01 vnivanch 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 | TestEm8 |
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| 9 | ------- |
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| 10 | |
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| 11 | Example for investigation of ionisation in thin absorbers and gaseous |
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| 12 | detectors |
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| 13 | |
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| 14 | 1- GEOMETRY DEFINITION |
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| 15 | |
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| 16 | The target is a cilinder made of a given material placed inside |
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| 17 | cilindrical container, which is placed inside the world volume. |
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| 18 | |
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| 19 | Following parameters define the geometry: |
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| 20 | - the material of the target, |
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| 21 | - the thickness of the target, |
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| 22 | - the radius of the target, |
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| 23 | - the material of the container, |
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| 24 | - the thickness of the container, |
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| 25 | - the material of the world. |
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| 26 | |
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| 27 | The list of materials used in gaseous detectors are built inside |
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| 28 | the DetectorConstruction class, also NIST materials are availabe. |
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| 29 | The default geometry is provided but all parameters can be changed via |
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| 30 | UI commands defined in the DetectorMessenger class, for example, |
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| 31 | |
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| 32 | /testem/setGasMat XeCH4C3H8 |
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| 33 | /testem/setWindowMat G4_MYLAR |
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| 34 | /testem/setWorldMat G4_AIR |
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| 35 | /testem/setGasThick 10 cm |
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| 36 | /testem/setGasRad 20 cm |
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| 37 | /testem/setWindowThick 50 um |
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| 38 | |
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| 39 | |
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| 40 | 2- AN EVENT : THE PRIMARY GENERATOR |
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| 41 | |
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| 42 | The primary kinematic consists of a single particle which hits the |
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| 43 | absorber perpendicular to the input face. The type of the particle |
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| 44 | and its energy can be set via the G4 build-in commands of ParticleGun |
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| 45 | A RUN is a set of events. |
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| 46 | |
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| 47 | 3- DETECTOR RESPONSE |
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| 48 | |
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| 49 | The TargetSD class sending information about each step inside the target |
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| 50 | to the HistoManager class scoring of energy deposition in the detector. |
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| 51 | Additionally at each step of a particle inside the target the number of |
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| 52 | ionisation clusters is sampled using G4ElectronIonPair helper class. The |
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| 53 | parameter of transformation of energy into ionisation clusters can be |
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| 54 | set via UI command: |
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| 55 | |
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| 56 | /testem/setPairEnergy 19 eV |
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| 57 | |
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| 58 | |
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| 59 | 4- PHYSICS |
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| 60 | |
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| 61 | The particle's type and the physic processes which will be available |
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| 62 | in this example are set in PhysicsList class, which uses Geant4 |
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| 63 | EM physics constructors providing in the physics_list library. |
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| 64 | |
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| 65 | The messenger classes introduce interactive commands. In particular, |
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| 66 | PAI ionisation model can be added using G4EmConfurator helper class, |
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| 67 | which is invokated by the UI command |
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| 68 | |
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| 69 | /testem/phys/addPhysics pai |
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| 70 | |
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| 71 | 5- HOW TO START ? |
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| 72 | |
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| 73 | - compile and link to generate an executable |
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| 74 | % cd TestEm8 |
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| 75 | % gmake |
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| 76 | |
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| 77 | - execute TestEm8 in 'batch' mode from macro files e.g. |
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| 78 | % $(G4INSTALL)/bin/$(G4SYSTEM)/TestEm8 TestEm8.in |
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| 79 | |
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| 80 | - execute TestEm8 in 'interactive' mode with visualization e.g. |
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| 81 | % $(G4INSTALL)/bin/$(G4SYSTEM)/TestEm8 |
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| 82 | .... |
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| 83 | Idle> type your commands |
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| 84 | .... |
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| 85 | |
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| 86 | |
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| 87 | |
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| 88 | |
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