1 | ------------------------------Advanced Example--------------------------------- README FILE |
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2 | |
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3 | |
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4 | NB: The documentation for this example is in the process of being updated. |
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5 | Please go to http://www.ge.infn.it/geant4/examples/ for the most up-to-date |
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6 | description, manual, design documentation and users requirement/traceability. |
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7 | |
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8 | JUNE 2002: |
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9 | The underground physics example has been updated since the December Geant4.0 |
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10 | release to include: 1) Analysis, using AIDA 2.2 and tested against Anaphe 4.0 |
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11 | 2) Full lab geometry - important for neutron scattering |
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12 | 3) Updated macros/messengers |
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13 | 4) Correction of a few minor features |
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14 | |
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15 | The messengers can be seen from typing help within the UI. |
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16 | Additional file handling and time/energy cut messengers have been implemented. |
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17 | |
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18 | (1) and (2) are discussed more fully below |
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19 | |
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20 | Note: Due to the importation of data files during the initialisation stage of |
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21 | Geant4, load-time may be in excess of 5 minutes. |
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22 | |
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23 | UNDERGROUND PHYSICS |
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24 | |
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25 | An example of a underground dark matter experiment. |
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26 | |
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27 | Please see the UserRequirements.txt and related web-pages referred to |
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28 | at the end of that document. |
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29 | |
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30 | Over-view: |
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31 | A single liquid xenon cell is simulated within Geant4 and the scintillation |
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32 | light produced from interactions from various calibration species is recorded |
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33 | as PhotoMultiplier hits. The output is then written to an ASCII file for |
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34 | future off-line analysis. |
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35 | |
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36 | Geometry: |
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37 | Experimental set-up: |
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38 | |
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39 | G4double worldWidth = 470.0*cm + 2.*wallThick; // "x" |
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40 | G4double worldLength = 690.0*cm + 2.*wallThick; // "y" |
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41 | G4double worldHeight = 280.0*cm + 2.*wallThick; // "z" |
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42 | |
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43 | |
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44 | |
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45 | A "cavern" of dimensions 5.18m x 7.38m x 3.28m with concrete walls is defined |
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46 | as the World Volume. A laboratory geometry is incorporated included desks, |
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47 | cupboards, door and windows. For ease this is included in a separate ".icc" |
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48 | file which can be removed should the code seem cumbersome. In the centre of |
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49 | the cavern a steel vacuum vessel containing liquid and gaseous xenon is placed. |
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50 | The internal construction of the vessel accurately reproduces an existing |
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51 | prototype Dark Matter detector which allows experimental comparison. The active |
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52 | detector volume is defined by a series of metal rings, complemented by |
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53 | a cover mirror and a PMT immersed in the liquid. Two grids and a |
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54 | thermalising copper shield are also incorporated. The liquid/gas |
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55 | interface is located 6mm away from the mirror surface. A Am241 |
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56 | calibration source is suspended from one of the grids in the liquid |
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57 | phase, above the PMT. |
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58 | |
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59 | XXX================XXX mirror |
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60 | XXX________________XXX gas phase |
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61 | XXX XXX |
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62 | XXX XXX liquid phase |
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63 | XXX XXX |
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64 | XXX.......U........XXX grid + calibrator |
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65 | XXX................XXX grid |
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66 | XXX| |XXX |
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67 | | ___------___ | |
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68 | || PMT || |
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69 | || || |
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70 | |
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71 | |
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72 | Hits Output (file "hits.out"): |
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73 | An ASCII file containing the following information: |
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74 | Evt # : event number |
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75 | Etot, MeV : energy deposited in liquid xenon |
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76 | LXe hits : number of hits in liquid xenon |
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77 | LXeTime, ns : time of first hit in liquid xenon |
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78 | PMT hits : number of hits in PMT (photocathode) |
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79 | PmtTime, ns : average PMT hit time relative to LXeTime |
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80 | First hit : first particle to hit liquid xenon |
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81 | Flags : particles contributing to energy deposition |
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82 | Seeds : the initial seed values for given hit events |
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83 | |
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84 | Note: |
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85 | |
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86 | The time information PmtTime is erroneous when forcing nuclear |
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87 | decay with the RadioactiveDecay module due to the precision |
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88 | required to detect nanosecond scintillation times on a global |
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89 | time of 432 years (in the case of 241Am decay). |
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90 | |
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91 | |
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92 | Pmt Output (file "pmt.out"): |
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93 | Photon hit positions within the PMT face (overwritten every event): |
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94 | "Hit# X, mm Y, mm Z, mm" |
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95 | |
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96 | |
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97 | To Run: |
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98 | Either run the macro files interactively or in batch with the command |
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99 | DMX macro_name.mac. |
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100 | |
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101 | |
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102 | Macros: |
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103 | |
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104 | initInter.mac |
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105 | Initialisation macro for interactive mode. |
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106 | |
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107 | gamma.mac |
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108 | Shoots one 60 keV gamma upwards from the calibrator and traces the |
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109 | scintillation light produced in LXe to the PMT. All tracks are drawn |
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110 | with custom colours. PMT hits in photocathode are also shown. Event |
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111 | summary is writen to file "hits.out". |
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112 | |
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113 | gamma_1000.mac |
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114 | Similar to above, but 1000 gammas are emmited isotropically from the |
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115 | source. No hits or tracks are draw, and the verbosity is reduced. |
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116 | |
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117 | alpha.mac |
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118 | Shoots one 5.486 MeV alpha particle upwards from the calibrator and |
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119 | traces the scintillation light to the PMT. All tracks except |
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120 | optical photons are drawn. Event summary is written to file |
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121 | "hits.out" and PMT hits to file "pmt.out". |
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122 | |
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123 | alpha_1000.mac |
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124 | Similar to above, but 1000 alphas are emmited isotropically from the |
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125 | source. No tracks are stored, and the verbosity is reduced. Event |
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126 | summary is written to file "hits.out", PMT hits are not written out. |
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127 | |
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128 | neutron.mac |
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129 | Shoots one 2.48 MeV neutron inside the room aimed at the detector. |
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130 | All tracks except scintillation photons are drawn (custom colours). |
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131 | Gammas are not killed at the concrete wall. Event summery is written |
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132 | to file "hits.out". |
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133 | |
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134 | ambe_spectrum.mac |
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135 | Produces a spectrum of neutrons according to an approximation of a Am/Be |
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136 | neutron source. However, this uses the GPS and therefore will only work |
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137 | after compilation with the DMXENV_GPS_USE environment variable (see below) |
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138 | |
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139 | |
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140 | sourceAm241.mac |
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141 | Forces the decay of 241Am nuclei in the calibrator and tracks the |
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142 | resulting particles (237Np + alpha + gamma from 237Np |
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143 | de-excitation). All tracks are drawn except scintillation photons. |
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144 | Event summery is written to file "hits.out". |
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145 | -> To be added for a future release |
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146 | |
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147 | |
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148 | sourceAm241_1000.mac |
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149 | Similar to above but for 1000 events. No tracks are stored. |
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150 | -> To be added for a future release |
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151 | |
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152 | |
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153 | Note: |
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154 | The following environment variables need to be set: |
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155 | G4RADIOACTIVEDATA : points to Radioactive Decay Data files |
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156 | G4LEDATA : points to low energy data base |
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157 | G4LEVELGAMMADATA : points to PhotoEvaporation data |
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158 | NeutronHPCrossSections : points to neutron data files |
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159 | |
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160 | In addition if you require to use the full General Particle Source then the |
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161 | variable DMXENV_GPS_USE can be set. The DMX gun is still included in order to |
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162 | allow forward compatibility should the GPS change. |
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163 | |
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164 | |
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165 | ANALYSIS: |
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166 | |
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167 | In order to use the AIDA 3.2.1 compliant analysis set the environment variable |
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168 | G4ANALYSIS_USE before building. If a previous build exists a gmake clean has |
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169 | to be executed. |
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170 | |
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171 | setenv G4ANALYSIS_USE 1 |
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172 | |
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173 | then gmake |
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174 | |
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175 | The program should then produce hbook histogram files |
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176 | |
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177 | Using AIDA 3.2.1 interfaces three different analysis packages can be utilised: |
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178 | Java Analysis Studio (JAS) |
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179 | OpenScientist |
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180 | PI |
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181 | |
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182 | Please for more information look at http://aida.freehep.org |
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183 | |
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184 | SEEDS: |
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185 | |
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186 | The seeds of event hits are stored in the hit record file. These can be used |
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187 | to repeat events for visualisation, test crashes/idiosyncracies: |
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188 | |
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189 | /random/setDirectoryName ./seeds |
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190 | /random/resetEngineFrom currentEvent.rndm |
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191 | /random/saveThisEvent |
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192 | /random/setSavingFlag |
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193 | |
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194 | The file currentEvent.rndm should contain the two seeds which were outputed in |
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195 | the scintHit file. |
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196 | |
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197 | ERRORS: |
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198 | |
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199 | When running interactively the following error will be shown: |
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200 | |
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201 | BooleanProcessor::caseIE : unimplemented case |
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202 | BooleanProcessor::caseIE : unimplemented case |
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203 | BooleanProcessor::caseIE : unimplemented case |
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204 | BooleanProcessor::caseIE : unimplemented case |
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205 | BooleanProcessor::caseIE : unimplemented case |
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206 | BooleanProcessor::caseIE : unimplemented case |
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207 | BooleanProcessor: boolean operation failed |
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208 | BooleanProcessor::caseIE : unimplemented case |
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209 | BooleanProcessor::caseIE : unimplemented case |
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210 | BooleanProcessor::caseIE : unimplemented case |
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211 | BooleanProcessor::caseIE : unimplemented case |
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212 | BooleanProcessor: boolean operation failed |
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213 | |
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214 | This is a "feature" of the visualisation of boolean volumes, but does not |
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215 | affect functionality/performance so can be ignored. |
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216 | |
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217 | NB: |
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218 | If using explicit libraries (?) i.e. non-shared then compilation time with |
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219 | neutrons in physics list is very long (>5 minutes) - check this............. |
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220 | It is more efficient to use shared libraries that are loaded at run-time with |
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221 | increased initialisation time (at run-time). |
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222 | |
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223 | Also if using shared libraries the load time at run-time may be several minutes |
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224 | - this is partially due to the neutron implementation requires full data sets |
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225 | for each isotope being specified. |
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226 | |
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227 | |
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228 | -------------------------------------- |
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229 | |
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230 | If running on Redhat 7.0 or above set G4SYSTEM to Linux-g++, alternatively you |
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231 | can install backward compatibility to egcs, however, requires |
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232 | config/sys/Linux-egcs.gmk to be altered so that CXX is set to kgcc |
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233 | (compared to g++ in original file) |
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234 | |
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235 | -------------------------------------- |
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236 | |
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237 | |
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238 | Alex Howard, 29/11/01 |
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239 | updated 18/06/02 |
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240 | |
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