[807] | 1 | $Id: README,v 1.4 2005/12/09 16:44:21 mkossov 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 | Photon_Inefficiency (raredecay_calorimetry) advanced example |
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| 9 | ------------------------------------------------------------ |
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| 10 | |
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| 11 | |
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| 12 | This example simulates a simplified sandwitch calorimeter (developed from N07). |
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| 13 | The main features in this example to be demonstrated are: |
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| 14 | |
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| 15 | 1. How to use a user's run class derived from the G4Run base class for accumulating |
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| 16 | physics values and hits to make the run result; |
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| 17 | |
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| 18 | 2. How to change calorimeter geometry without re-building a world volume; |
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| 19 | |
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| 20 | 3. How to change materials which are used in parameterized volumes; |
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| 21 | |
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| 22 | 4. How to instantiate more than one sensitive detectors with different |
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| 23 | module names from only one sensitive detector class; |
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| 24 | |
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| 25 | 5. How to define geometrical regions and set production thresholds for each readout |
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| 26 | region; |
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| 27 | |
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| 28 | 6. How to Estimate importance of photonuclear reactions for photon inefficiency of |
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| 29 | calorimeters; |
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| 30 | |
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| 31 | 7. How to compare effectiveness of different absorbers to reduce photon inefficiency. |
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| 32 | |
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| 33 | 8. How to use macro files in the batch and interactive modes. |
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| 34 | |
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| 35 | 9. How to make the user's UI commands (/PhotIn/ in this example). |
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| 36 | |
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| 37 | 1- Utilizing a run class derived from the G4Run base class for accumulating energy |
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| 38 | depositions and hits for the run result: |
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| 39 | |
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| 40 | G4Run is a class which users can inherit and create their own class for accumulating |
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| 41 | useful information. It has a virtual method RecordEvent(const G4Event*), which is |
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| 42 | called by G4RunManager class at the end of event processing. By implemeting this method |
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| 43 | in the user's run class, one can store information associated with G4Event class and |
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| 44 | hit collections attached to the G4Event class. The PhotInRun class is a class derived |
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| 45 | from the G4Run class. In the PhotInRun::RecordEvent(const G4Event*) method events are |
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| 46 | counted and all hit collections are accessed to accumulate energy depositions, step |
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| 47 | lengths and numbers of steps. |
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| 48 | |
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| 49 | When users create run classes, objects of these classes must be instantiated in the |
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| 50 | GenerateRun() method of the class derived from G4UserRunAction base class. The pointer |
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| 51 | to the run object must be returned by this method. A PhotInRunAction class instantiates |
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| 52 | PhotInRun class object. In the PhotInRunAction::EndOfRunAction(const G4Run*) method, |
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| 53 | PhotInRun object is analized to make the output run summary. |
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| 54 | |
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| 55 | Generated secondary particles is collected in the PhotInStackinAction class instead of |
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| 56 | the sensitive detector class. A PhotInStackingAction::ClassifyNewTrack(const G4Track*) |
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| 57 | method is used not for tracks which are sent to the stack, but for accessing all |
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| 58 | secondaries generated in the event. |
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| 59 | |
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| 60 | 2- Changing calorimeter geometry without re-building a world volume: |
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| 61 | |
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| 62 | In PhotINDetectorConstruction, all solids, logical and physical volumes are constructed |
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| 63 | only once in the first Constuct() method. Positions and numbers of slices are changed |
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| 64 | not by re-constructing new objects but by modifying data members of already existing |
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| 65 | objects as it's implemented in the PhotInDetectorConstruction::SetNumberOfLayers(G4int) |
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| 66 | method for showing how to change the number of the parameterized volumes, and also in |
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| 67 | the PhotInDetectorConstruction::SetSerialGeometry(G4bool) method as an example of |
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| 68 | changing positions of the placed volumes. |
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| 69 | |
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| 70 | 3- Changing materials already used in parameterized volumes: |
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| 71 | |
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| 72 | Materials of absorbers and of the sensitive gap in the calorimeter are defined by the |
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| 73 | PhotInGapParameterisation::ComputeMaterial(const G4int,G4VPhysicalVolume*) method. |
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| 74 | Positions of each layer in the calorimeter have to be defined by the method |
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| 75 | PhotInGapParameterisation::ComputeTransformation(const G4int,G4VPhysicalVolume*). |
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| 76 | |
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| 77 | 4- Instantiating more than one sensitive detectors with different module names using only |
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| 78 | one sensitive detector class: |
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| 79 | |
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| 80 | The PhotInCalorimeterSD class is constructed three times with deferent module names in |
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| 81 | the PhotInDetectorConstruction::Construct() method. Each detector creates two hits |
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| 82 | collections (PhotInCalorHit class). In total six hits collections of the same type are |
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| 83 | created for each event. To access each of six collections in the PhotInEventAction |
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| 84 | method both the module name and the collection name are used. |
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| 85 | |
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| 86 | 5- Defining geometrical regions and setting production thresholds for each region: |
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| 87 | |
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| 88 | Setting production thresholds (so-called production cuts) to individual region of the |
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| 89 | detector geometry is a new feature provided by Geant4 5.1 release. This feature is also |
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| 90 | called as "Cuts per region". Please, note that this new feature is supporsed to be used |
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| 91 | only by users, |
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| 92 | a) who are simulating complex geometry (such as LHC detectors); |
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| 93 | b) and who has enough experience of simulating EM showers in matter. |
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| 94 | It is strongly recommended to compare simulated results of this new feature with the |
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| 95 | results of the same geometry but with uniform production thresholds. Setting different |
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| 96 | cuts for each region may break coherent and comprehensive accuracy of simulation. Such |
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| 97 | regional cuts must be carefully optimized by users comparing results with uniform cuts. |
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| 98 | |
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| 99 | In the PhotInDetectorConstruction::Construct(), three objects of the G4Region class are |
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| 100 | instantiated and set to the logical volumes of each of three calorimeter modules. Also, |
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| 101 | these individual logical volumes are registered as "root logical volumes" so that all |
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| 102 | daghter volumes in the logical volumes are also affected by the corresponding regions. |
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| 103 | |
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| 104 | In the PhotInPhysicsList::SetCuts() method, in addition to set of the default threshold |
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| 105 | values for the world volume, three thresholds are set to three calorimeter regions |
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| 106 | respectively. Setting a production threshold to a region, gamma, electron, or positron |
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| 107 | are not generated as a secondary if its range is shorter than the production threshold |
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| 108 | for the particular region. Please note, that at present some EM processes still |
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| 109 | generate such secondaries below threshold. |
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| 110 | |
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| 111 | 6- Estimating importance of photonuclear reactions for photon inefficiency of detectors: |
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| 112 | |
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| 113 | User can switch on or off the photo- (and electro-) nuclear processes for the run. |
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| 114 | |
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| 115 | 7- Compare effectiveness of different absorbers to reduce the photon inefficiency: |
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| 116 | |
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| 117 | User can compare results of simulation for different materials of absorbers. |
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| 118 | |
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| 119 | 8- Macro files: |
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| 120 | |
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| 121 | Batch mode: ">./PhotIn < PhotIn.in" (It creates a reference output file PhotIn.out) |
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| 122 | |
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| 123 | Interactive mode: ">./PhotIn". |
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| 124 | Print "/control/execute sample.mac" when "Idle>" prompt appears. |
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| 125 | or (as the sam="/control/execute sample.mac" alias is define in vis.mac) |
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| 126 | Print "Idle> sam" |
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| 127 | |
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| 128 | Setting visualization parameters: The "vis.mac" macro file will be called automatically |
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| 129 | when the interactive execution starts. |
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| 130 | |
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| 131 | 9- UI commands defined in the "Photon_inefficiency" example: |
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| 132 | |
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| 133 | -------------------------------------------------- |
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| 134 | |
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| 135 | Command : /PhotIn/projParticle |
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| 136 | Guidance: Select Incident Beam Particle. |
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| 137 | |
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| 138 | Parameter : particle |
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| 139 | Parameter type: s |
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| 140 | Omittable : False |
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| 141 | Candidates : < List of all Geant4 particles> |
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| 142 | |
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| 143 | -------------------------------------------------- |
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| 144 | |
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| 145 | Command : /PhotIn/projEnergy |
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| 146 | Guidance: Select Energy for the Beam Particle. |
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| 147 | |
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| 148 | Parameter : Energy |
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| 149 | Parameter type: d |
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| 150 | Omittable : False |
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| 151 | |
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| 152 | -------------------------------------------------- |
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| 153 | |
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| 154 | Command : /PhotIn/setAbsMat |
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| 155 | Guidance: Select Material of the Absorber. |
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| 156 | |
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| 157 | Parameter : choice |
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| 158 | Parameter type: s |
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| 159 | Omittable : False |
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| 160 | Candidates : Aluminium liquidArgon Lead Water Scintillator Air Galactic |
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| 161 | |
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| 162 | -------------------------------------------------- |
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| 163 | |
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| 164 | Command : /PhotIn/setGapMat |
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| 165 | Guidance: Select Material of the Gap. |
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| 166 | |
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| 167 | Parameter : choice |
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| 168 | Parameter type: s |
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| 169 | Omittable : False |
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| 170 | Candidates : Aluminium liquidArgon Lead Water Scintillator Air Galactic |
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| 171 | |
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| 172 | -------------------------------------------------- |
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| 173 | |
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| 174 | Command : /PhoyIn/numberOfLayers |
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| 175 | Guidance: Set number of layers. |
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| 176 | Range of parameters : nl>0 |
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| 177 | |
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| 178 | Parameter : nl |
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| 179 | Parameter type: i |
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| 180 | Omittable : False |
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| 181 | |
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| 182 | -------------------------------------------------- |
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| 183 | |
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| 184 | Command : /PhoyIn/numberOfSlabs |
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| 185 | Guidance: Set number of slabs in a layer. |
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| 186 | Range of parameters : nl>0 |
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| 187 | |
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| 188 | Parameter : nl |
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| 189 | Parameter type: i |
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| 190 | Omittable : False |
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| 191 | |
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| 192 | -------------------------------------------------- |
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| 193 | |
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| 194 | Command : /PhotIn/serialGeometry |
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| 195 | Guidance: Select calorimeters to be placed in serial or parallel. |
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| 196 | |
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| 197 | Parameter : serialize |
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| 198 | Parameter type: b |
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| 199 | Omittable : False |
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| 200 | |
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| 201 | -------------------------------------------------- |
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| 202 | |
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| 203 | Command : /PhotIn/verbose |
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| 204 | Guidance: Set verbosity of each event. |
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| 205 | Range of parameters : vl>=0 && vl<10 |
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| 206 | |
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| 207 | Parameter : vl |
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| 208 | Parameter type: i |
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| 209 | Omittable : True |
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| 210 | Default value : taken from the current value |
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| 211 | |
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| 212 | -------------------------------------------------- |
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| 213 | |
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| 214 | General comments about the structure of the example: |
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| 215 | ==================================================== |
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| 216 | |
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| 217 | 0. In all .cc files the debug flags can be defined. To make program silent comment them. |
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| 218 | In some .cc files the errors flag is defined. It permits run time warnings (if ever). |
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| 219 | |
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| 220 | 1. All constants of the example, names, and default values for the variable parameters are |
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| 221 | collected in the include/PhotInConstants.hh header widely used in almost all classes. |
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| 222 | |
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| 223 | 2. The src/PhotInHit collection is practically a structure for three values: energy |
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| 224 | deposition of charged particles, track length of neutrons, and #of steps. Hits are |
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| 225 | collected PhotInCalorHitsCollection's defined in include/PhotInCalorHit.hh. |
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| 226 | |
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| 227 | 3. PhotInCalorimeterSD class defines and treats 6 (two per detector: one for absorber, one |
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| 228 | for the active slabs) hit collections, so absorber is defined as a sensitive detector. |
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| 229 | |
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| 230 | 4. All cuts are made in the PhotInPhysicsList::SetCuts(), while in future cuts can be more |
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| 231 | complicated than the scaling of the standard cuts and can be out of the Physics List. |
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| 232 | |
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| 233 | The dependency structure (general Constants.hh and PhotIn prefix is skipped). |
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| 234 | ============================================================================= |
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| 235 | |
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| 236 | .____________________________________________________________Main________. |
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| 237 | | / / / / | | | |
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| 238 | | VisManager PhysicsList / DetectorMessenger | RunAction | |
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| 239 | | / / / \ \ | | | |
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| 240 | \ PrimaryGeneratorAction / \ \ | Run* EventAction |
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| 241 | \ | / \ \ | | / / |
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| 242 | -----------------DetectorConstruction \ StackingAction / |
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| 243 | / | \ \ / |
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| 244 | LayerParameterization GapParameterization CalorimeerSD \ / |
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| 245 | | \ / |
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| 246 | (defined in the "CalorHit" as a type) CalorHitsCollection \ / |
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| 247 | \ \ / |
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| 248 | CalorHit |
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| 249 | |
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| 250 | |
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| 251 | * SteppingAction is a debuging tool which can be optionally attached to the RunManager |
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| 252 | ========================================================================================= |
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| 253 | |
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| 254 | Description of classes: |
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| 255 | ======================= |
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| 256 | |
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| 257 | "CalorHit" handles (Reset/Add/Get) EnergyDeposition, TrackLengt, NumberOfSteps of the Hit |
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| 258 | (+ "CalorHitsCollection" a container for CalorHits in different parts of the detector) |
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| 259 | |
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| 260 | "CalorimeerSD" SensetiveDetector, nLay & nSlab definition, Layers & Slabs HitsCollections |
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| 261 | |
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| 262 | "LayerParameterization" & "GapParameterization" parameterization of Layers & Slabs |
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| 263 | |
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| 264 | "DetectorConstruction" create, change, and replace three calorimeters of the example |
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| 265 | |
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| 266 | "StackingAction" calculates number of each kind of particles, their min & max energies |
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| 267 | |
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| 268 | "PrimaryGeneratorAction" ParticleGun of events changes kind of particle, energy, direction |
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| 269 | |
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| 270 | "DetectorMessenger" on flight change of the detector geometry, regions, and HitsCollections |
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| 271 | |
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| 272 | "Run" run manager which can treat/reset information about particles and their energy range |
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| 273 | |
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| 274 | "EventAction" & "RunAction" treat of the collected information of simulation |
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| 275 | |
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| 276 | "PhysicsList" defines physics (now is not used and ReferencePhysicsLists are used instead) |
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| 277 | |
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| 278 | "VisManager" defines a way of visualization of the particular/overlaped events |
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