1 | $Id: README,v 1.5 2007/05/04 01:49:28 asaim 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 | ExampleN07 |
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9 | ---------- |
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10 | |
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11 | |
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12 | This example simulates three simplified sandwitch calorimeters. |
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13 | The main features demonstrated in this example are : |
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14 | |
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15 | 1. Utilizing a concrete run class derived from G4Run base class for |
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16 | accumulating physics quantities for a run |
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17 | 2. Changing calorimeter geometries without re-building a world volume |
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18 | 3. Defining geometrical regions and setting production thresholds |
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19 | for each region |
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20 | 4. Demonstrating the use of primitive scorer and filter classes without |
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21 | implementing sensitive detector class |
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22 | 5. Demonstrating the use of parallel scoring geometry and associating |
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23 | parallel world scoring process |
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24 | 6. Measuring the timing spent for each region, both for all particle |
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25 | types and for e+/e- |
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26 | |
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27 | ********************************************************************** |
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28 | Note: Since this example utilizes its own ExN07SteppingVerbose for the |
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29 | timing measurement, the user cannot get the ordinary verbosity with |
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30 | /tracking/verbose. |
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31 | ********************************************************************** |
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32 | |
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33 | 1- Utilizing a concrete run class derived from G4Run base class for |
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34 | accumulating physics quantities for a run |
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35 | |
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36 | G4Run is a class the user can inherit and create his/her own concrete |
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37 | class for accumulating information useful to him/her. It has a virtual |
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38 | method RecordEvent(const G4Event*), which will be invoked by G4RunManager |
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39 | at the end of processing each event. By implemeting this method in the |
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40 | user'r concrete run class, he/she can store information associating with |
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41 | G4Event class itself and hits collections attached with G4Event. In this |
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42 | example, ExN07Run is the class derived from G4Run. In the method |
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43 | ExN07Run::RecordEvent(const G4Event*), in addition to counting the |
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44 | number of events, all hits collections are accessed to accumulate |
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45 | energy depositions, step lengths and number of steps. |
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46 | |
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47 | In case the user create his/her own run class, an object of this class |
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48 | must be instantiated in the method GenerateRun() of his/her concrete |
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49 | class derived from G4UserRunAction base class. The pointer to this run |
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50 | object must be returned by this method. In this example, ExN07RunAction |
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51 | is the class which instantiating ExN07Run class object. In |
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52 | ExN07RunAction::EndOfRunAction(const G4Run*) method, ExN07Run object |
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53 | is analized to output the run summary. |
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54 | |
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55 | It should be noted that some information about generated secondaries |
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56 | are collected in ExN07StackinAction instead of sensitive detector class. |
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57 | ExN07StackingAction::ClassifyNewTrack(const G4Track*) method is used |
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58 | not for classifying tracks sent to the stack, but for accessing to all |
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59 | secondaries generated in an event. |
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60 | |
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61 | 2- Changing calorimeter geometries without re-building a world volume |
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62 | |
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63 | In ExN07DetectorConstruction, all solids, logical and physical volumes |
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64 | are constructed only once at the first invocation of Constuct() method. |
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65 | Positions and number of slices are changed not by re-constructing another |
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66 | objects but by modifying data members of already existing objects as |
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67 | it is implemented in ExN07DetectorConstruction::SetNumberOfLayers(G4int) |
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68 | for changing the number of parameterized volumes, and also |
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69 | ExN07DetectorConstruction::SetSerialGeometry(G4bool) for changing the |
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70 | position of placed volumes. |
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71 | |
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72 | 3- Defining geometrical regions and setting production thresholds |
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73 | for each region |
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74 | |
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75 | Setting production thresholds (so-called production cuts) to individual |
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76 | region of a detector geometry is the new feature provided by Geant4 5.1 |
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77 | release. This feature is also called as "Cuts per region". |
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78 | |
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79 | Please note that this new feature is supporsed to be used only by the |
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80 | users, |
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81 | a) who is simulating most complex geometry such as an LHC detector, |
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82 | b) and who has enough experience of simulating EM showers in matter. |
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83 | We strongly recommend to compare the simulated results of this new |
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84 | feature with the results of the same geometry but having uniform |
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85 | production thresholds. Setting completely different cut values for |
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86 | individual region may break the coherent and comprehensive accuracy |
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87 | of the simulation. Thus such cut values should be carefully optimized |
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88 | by the user with comparison with results of uniform cuts. |
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89 | |
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90 | In ExN07DetectorConstruction::Construct(), Three objects of G4Region |
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91 | class are instantiated and set to the logical volumes of each of three |
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92 | calorimeter modules. Also, these individual logical volumes are |
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93 | registered as "root logical volume" so that all daghter volumes in |
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94 | these logical volumes are also affected by the corresponding regions. |
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95 | |
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96 | In ExN07PhysicsList::SetCuts(), in addition to set the default threshold |
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97 | values for the world volume, three threshold values are set to three |
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98 | calorimeter regions respectively. By setting production thresholds to |
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99 | a region, gamma, electron or positron will not be generated as a |
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100 | secondary if its range is shorter than the production threshold of that |
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101 | particular region. Please note that some EM processes still generate |
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102 | such secondary below threshold. |
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103 | |
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104 | 4- Demonstrating the use of primitive scorer and filter classes without |
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105 | implementing sensitive detector class |
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106 | |
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107 | In ExN07DetectorConstruction::SetupDetector() method, concrete classes |
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108 | G4PSEnergyDeposit, G4PSNofSecondary, G4PSTrackLength, G4PSNofStep and |
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109 | G4PSMinKinEAtGeneration, all of thich are derivalable of G4VPrimitiveScorer, |
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110 | are used to define the sensitivity of the calorimeter. All of them are |
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111 | registered to G4MultiFunctionalDetector and this detector object is set |
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112 | to the logical volume. G4SDParticleFilter is used to define the particle |
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113 | type(s) to be scored. |
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114 | |
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115 | In ExN07Run::RecordEvent() method, the way of retreiving G4THitsMap |
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116 | from each primitive scorer via G4HCofThisEvent is demonstrated. |
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117 | In ExN07RunAction::EndOfRunAction(), Run is summarized with data kept |
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118 | in ExN07Run class object. |
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119 | |
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120 | 5- Demonstrating the use of parallel scoring geometry and associating |
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121 | parallel world scoring process |
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122 | |
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123 | In ExN07PhysicsList::ConstructGeneral(), G4ParallelWorldScoringProcess is |
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124 | assigned to all the particle types. This process invokes sensitive detectors |
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125 | (and scorers) defined in the parallel world "ParallelScoringWorld", the |
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126 | name of the parallel world which is defined in main() (exampleN07.cc) as |
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127 | an argument of ExN07ParallelWorld constructor. |
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128 | |
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129 | As implemented in ExN07ParallelWorld::SetupGeometry(), the world volume of |
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130 | the parallel world is obtained by GetWorld() method as a clone copy of the |
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131 | world volume of the mass geometry. The user should not create the world volume. |
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132 | |
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133 | ExN07ParallelWorld defines three cylindrical volumes, each of them is |
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134 | located at the same position as three sandwitch calorimeters defined |
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135 | in the mass geometry (ExN07DetectorConstruction). Each cylinder is replicated |
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136 | in Rho to define 20 layers, and scores the same quantities as the mass geometry. |
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137 | These three cylinders are relocated accordingly when the mass geometry is |
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138 | modified by ExN07DetectorConstruction::SetSerialGeometry(). |
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139 | |
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140 | 6- Measuring the timing spent for each region, both for all particle |
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141 | types and for e+/e- |
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142 | |
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143 | ExN07SteppingVerbose class has two G4SliceTimer class objects for each |
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144 | detector region. One G4SliceTimer is measuring the time spent by a step |
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145 | in a region for all types of particles, and another is measuring for |
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146 | e+/e- only. |
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147 | |
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148 | ExN07SteppingVerbose::InitializeTimers() is invoked by ExN07RunAction:: |
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149 | BeginOfRunAction(), and checks the number of regions appear in the |
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150 | geometry and instantiates the necessary number of timers. Thus, this |
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151 | ExN07SteppingVerbose class can be used for any kind of geometry the user |
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152 | defines without any modification. Given G4VSteppingVerbose is not invoked |
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153 | if the verbosity of G4SteppingManager is 0, this verbosity is set to 1. |
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154 | |
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155 | NewStep() and StepInfo() are the methods defined in G4VSteppingVerbose |
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156 | base class, and they are invoked at the beginning and the end of every |
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157 | step, respectively, from G4SteppingManager. Thus, these methods are |
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158 | utilized in ExN07SteppingVerbose to start/resume and pause the timer. |
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159 | |
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160 | ExN07SteppingVerbose::Report() method is used by ExN07RunAction:: |
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161 | EndOfRunAction() to get the timing measured. |
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162 | |
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163 | 7- Macro files |
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164 | |
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165 | exampleN07.in |
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166 | To be used for batch mode. The reference output file is made by this |
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167 | macro file. |
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168 | |
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169 | sample.mac |
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170 | To be used for interactive mode. Issue "/control/execute sample.mac" |
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171 | when "Idle>" prompt appears. |
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172 | |
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173 | vis.mac |
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174 | Setting visualization parameters. This macro file will be called |
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175 | automatically when interactive execution starts. |
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176 | |
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177 | 8- UI commands defined in this example |
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178 | |
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179 | Command /N07/setAbsMat |
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180 | Guidance : |
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181 | Select Material of the Absorber. |
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182 | |
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183 | Parameter : choice |
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184 | Parameter type : s |
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185 | Omittable : False |
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186 | Candidates : Aluminium liquidArgon Lead Water Scintillator Air Galactic |
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187 | |
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188 | |
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189 | |
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190 | Command /N07/setGapMat |
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191 | Guidance : |
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192 | Select Material of the Gap. |
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193 | |
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194 | Parameter : choice |
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195 | Parameter type : s |
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196 | Omittable : False |
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197 | Candidates : Aluminium liquidArgon Lead Water Scintillator Air Galactic |
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198 | |
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199 | |
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200 | |
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201 | Command /N07/numberOfLayers |
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202 | Guidance : |
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203 | Set number of layers. |
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204 | Range of parameters : nl>0 |
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205 | |
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206 | Parameter : nl |
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207 | Parameter type : i |
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208 | Omittable : False |
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209 | |
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210 | |
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211 | |
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212 | Command /N07/serialGeometry |
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213 | Guidance : |
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214 | Select calorimeters to be placed in serial or parallel. |
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215 | |
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216 | Parameter : serialize |
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217 | Parameter type : b |
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218 | Omittable : False |
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219 | |
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220 | |
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