| 1 | $Id: README,v 1.5 2010/06/06 04:55:22 perl 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 | field01
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| 9 | -------
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| 10 |
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| 11 | Example enabling investigation of tracking in a magnetic field.
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| 12 | Electromagnetic processes also included.
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| 13 |
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| 14 |
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| 15 | 1- GEOMETRY DEFINITION
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| 16 |
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| 17 | The "absorber" is a solid made of a given material.
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| 18 |
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| 19 | Three parameters define the absorber :
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| 20 | - the material of the absorber,
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| 21 | - the thickness of an absorber,
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| 22 | - the transverse size of the absorber (the input face is a square).
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| 23 |
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| 24 | The volume "World" contains the "absorber".
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| 25 | In this test the parameters of the "World" can be changed , too.
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| 26 |
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| 27 | In addition a transverse uniform magnetic field can be applied.
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| 28 |
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| 29 | The default geometry is constructed in DetectorConstruction class,
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| 30 | but all the parameters can be changed via
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| 31 | the commands defined in the DetectorMessenger class.
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| 32 |
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| 33 | 2- AN EVENT : THE PRIMARY GENERATOR
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| 34 |
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| 35 | The primary kinematic consists of a single particle (proton, Ekin = 1 GeV)
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| 36 | which hits the
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| 37 | absorber perpendicular to the input face. The type of the particle
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| 38 | and its energy are set in the PrimaryGeneratorAction class, and can
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| 39 | be changed via the G4 build-in commands of ParticleGun class (see
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| 40 | the macros provided with this example).
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| 41 |
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| 42 | A RUN is a set of events.
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| 43 |
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| 44 | 3- DETECTOR RESPONSE
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| 45 |
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| 46 | The spatial distribution of charged particles transported in magnetic
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| 47 | field is envistigated.
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| 48 | A HIT is a record, event per event , of all the
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| 49 | informations needed to simulate and analyse the detector response.
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| 50 |
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| 51 | In this example a CalorHit is defined as a set of 2 informations:
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| 52 | - the total energy deposit in the absorber,
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| 53 | - the total tracklength of all charged particles in the absorber,
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| 54 |
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| 55 | Therefore the absorber is declared
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| 56 | 'sensitive detector' (SD), which means they can contribute to the hit.
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| 57 |
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| 58 | 4- PHYSICS DEMO
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| 59 |
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| 60 | The particle's type and the physic processes which will be available
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| 61 | in this example are set in PhysicsList class.
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| 62 |
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| 63 | The messenger classes introduce interactive commands . Using these
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| 64 | commands the geometry of the detector, the data of the primary
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| 65 | particle, etc. can be changed.
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| 66 |
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| 67 |
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| 68 | 5- HOW TO START ?
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| 69 |
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| 70 | - compile and link to generate an executable
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| 71 | % cd $G4INSTALL/example/extended/field/field01
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| 72 | % gmake
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| 73 |
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| 74 | - execute field01 in 'batch' mode from macro file e.g.
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| 75 | % $(G4INSTALL)/bin/$(G4SYSTEM)/field01 field01.in
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| 76 |
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| 77 | - execute field01 in 'interactive' mode with visualization e.g.
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| 78 | % $(G4INSTALL)/bin/$(G4SYSTEM)/field01
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| 79 | ....
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| 80 | Idle> /control/execute vis.mac
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| 81 | ....
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| 82 |
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| 83 |
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| 84 |
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