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12 | </A> |
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13 | <A HREF="index.html"> |
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14 | <IMG SRC="../../../../resources/html/IconsGIF/Contents.gif" ALT="Contents" HEIGHT=16 WIDTH=59></A> |
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15 | <A HREF="OptionalActions.html"> |
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19 | </TD> |
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20 | |
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21 | <TD ALIGN="Right"> |
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22 | <FONT COLOR="#238E23"><FONT SIZE=-1> |
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23 | <B>Geant4 User's Guide</B> <BR> |
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24 | <B>For Application Developers</B> <BR> |
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25 | <B>User Actions</B> </FONT></FONT> |
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26 | </TD> |
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27 | </TR> |
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28 | </TABLE> |
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29 | <P><BR> |
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30 | |
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31 | <CENTER><FONT COLOR="#238E23"><FONT SIZE=+3> |
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32 | <B>6.3 User Information Classes</B> |
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33 | </FONT></FONT> |
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34 | <BR><BR> |
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35 | </CENTER> |
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36 | |
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37 | <HR ALIGN="Center" SIZE="7%"> |
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38 | |
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39 | Additional user information can be associated with various Geant4 classes. |
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40 | There are basically two ways for the user to do this: |
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41 | <ul> |
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42 | <li>derive concrete classes from base classes used in Geant4. |
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43 | These are classes for run, hit, digit, trajectory and trajectory point, |
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44 | which are discussed in |
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45 | <a href="OptionalActions.html">6.2 for G4Run</a>, |
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46 | <a href="../Detector/hit.html">4.4 for G4VHit</a>, |
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47 | <a href="../Detector/digitization.html">4.5 for G4VDigit</a>, and |
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48 | <a href="../TrackingAndPhysics/tracking.html#5.1.6">5.1.6 for G4VTrajectory and G4VTrajectoryPoint</a> |
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49 | |
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50 | <li>create concrete classes from provided abstract base classes and |
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51 | associate them with classes used in Geant4. Geant4 classes which can |
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52 | accommodate user information classes are G4Event, G4Track, G4PrimaryVertex, |
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53 | G4PrimaryParticle and G4Region. These classes are discussed here. |
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54 | </ul> |
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55 | |
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56 | <a name="6.3.1"> |
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57 | <h2>6.3.1 G4VUserEventInformation</h2> |
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58 | |
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59 | <i>G4VUserEventInformation</i> is an abstract class from which the user can |
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60 | derive his/her own concrete class for storing user information associated |
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61 | with a G4Event class object. It is the user's responsibility to construct a |
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62 | concrete class object and set the pointer to a proper G4Event object. |
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63 | <p> |
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64 | |
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65 | Within a concrete implementation of G4UserEventAction, the |
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66 | SetUserEventInformation() method of G4EventManager may be used to set a |
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67 | pointer of a concrete class object to G4Event, given that the G4Event |
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68 | object is available only by "pointer to const". |
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69 | |
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70 | Alternatively, the user may modify the GenerateEvent() method of his/her |
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71 | own RunManager to instantiate a G4VUserEventInformation object and |
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72 | set it to G4Event. |
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73 | <p> |
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74 | The concrete class object is deleted by the Geant4 kernel when the |
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75 | associated G4Event object is deleted. |
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76 | |
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77 | <a name="6.3.2"> |
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78 | <h2>6.3.2 G4VUserTrackInformation</h2> |
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79 | |
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80 | This is an abstract class from which the user can derive his/her own |
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81 | concrete class for storing user information associated with a G4Track |
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82 | class object. It is the user's responsibility to construct a concrete |
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83 | class object and set the pointer to the proper G4Track object. |
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84 | <p> |
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85 | Within a concrete implementation of G4UserTrackingAction, the |
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86 | SetUserTrackInformation() method of G4TrackingManager may be used |
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87 | to set a pointer of a concrete class object to G4Track, |
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88 | given that the G4Track object is available only by "pointer to const". |
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89 | <p> |
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90 | The ideal place to copy a G4VUserTrackInformation object from a mother track |
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91 | to its daughter tracks is <i>G4UserTrackingAction::PostUserTrackingAction()</i>. |
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92 | <p> |
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93 | <center> |
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94 | <table border=1 cellpadding=10> |
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95 | <tr> |
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96 | <td> |
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97 | <pre> |
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98 | void RE01TrackingAction::PostUserTrackingAction(const G4Track* aTrack) |
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99 | { |
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100 | G4TrackVector* secondaries = fpTrackingManager->GimmeSecondaries(); |
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101 | if(secondaries) |
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102 | { |
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103 | RE01TrackInformation* info = (RE01TrackInformation*)(aTrack->GetUserInformation()); |
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104 | size_t nSeco = secondaries->size(); |
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105 | if(nSeco>0) |
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106 | { |
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107 | for(size_t i=0; i < nSeco; i++) |
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108 | { |
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109 | RE01TrackInformation* infoNew = new RE01TrackInformation(info); |
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110 | (*secondaries)[i]->SetUserInformation(infoNew); |
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111 | } |
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112 | } |
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113 | } |
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114 | } |
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115 | </pre> |
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116 | </td> |
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117 | </tr> |
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118 | <tr> |
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119 | <td align=center> |
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120 | Source listing 6.3.1<BR> |
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121 | <tt>Copying G4VUserTrackInformation from mother to daughter tracks</tt> |
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122 | </td> |
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123 | </tr> |
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124 | </table></center><p> |
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125 | The concrete class object is deleted by the Geant4 kernel when the |
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126 | associated G4Track object is deleted. In case the user wants to keep |
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127 | the information, it should be copied to a trajectory corresponding to |
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128 | the track. |
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129 | |
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130 | <a name="6.3.3"> |
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131 | <h2>6.3.3 G4VUserPrimaryVertexInformation and G4VUserPrimaryTrackInformation</h2> |
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132 | |
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133 | These abstract classes allow the user to attach information regarding the |
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134 | generated primary vertex and primary particle. Concrete class objects derived |
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135 | from these classes should be attached to <i>G4PrimaryVertex</i> and |
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136 | <i>G4PrimaryParticle</i> class objects, respectively. |
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137 | <p> |
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138 | The concrete class objects are deleted by the Geant4 Kernel when the |
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139 | associated G4PrimaryVertex or G4PrimaryParticle class objects are deleted |
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140 | along with the deletion of G4Event. |
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141 | |
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142 | <a name="6.3.4"> |
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143 | <h2>6.3.4 G4VUserRegionInformation</h2> |
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144 | |
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145 | This abstract base class allows the user to attach information associated |
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146 | with a region. For example, it would be quite beneficial to add some methods |
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147 | returning a boolean flag to indicate the characteristics of the region |
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148 | (e.g. tracker, calorimeter, etc.). With this example, the user can easily and |
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149 | quickly identify the detector component. |
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150 | <p> |
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151 | <center> |
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152 | <table border=1 cellpadding=10> |
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153 | <tr> |
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154 | <td> |
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155 | <pre> |
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156 | class RE01RegionInformation : public G4VUserRegionInformation |
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157 | { |
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158 | public: |
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159 | RE01RegionInformation(); |
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160 | ~RE01RegionInformation(); |
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161 | void Print() const; |
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162 | |
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163 | private: |
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164 | G4bool isWorld; |
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165 | G4bool isTracker; |
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166 | G4bool isCalorimeter; |
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167 | |
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168 | public: |
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169 | inline void SetWorld(G4bool v=true) {isWorld = v;} |
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170 | inline void SetTracker(G4bool v=true) {isTracker = v;} |
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171 | inline void SetCalorimeter(G4bool v=true) {isCalorimeter = v;} |
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172 | inline G4bool IsWorld() const {return isWorld;} |
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173 | inline G4bool IsTracker() const {return isTracker;} |
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174 | inline G4bool IsCalorimeter() const {return isCalorimeter;} |
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175 | }; |
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176 | </pre> |
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177 | </td> |
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178 | </tr> |
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179 | <tr> |
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180 | <td align=center> |
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181 | Source listing 6.3.2<BR> |
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182 | <tt>A sample region information class</tt> |
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183 | </td> |
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184 | </tr> |
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185 | </table></center> |
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186 | <p> |
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187 | The following code is an example of a stepping action. Here, a track is |
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188 | suspended when it enters the "calorimeter region" from the "tracker region". |
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189 | <p> |
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190 | <center> |
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191 | <table border=1 cellpadding=10> |
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192 | <tr> |
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193 | <td> |
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194 | <pre> |
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195 | void RE01SteppingAction::UserSteppingAction(const G4Step * theStep) |
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196 | { |
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197 | // Suspend a track if it is entering into the calorimeter |
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198 | |
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199 | // check if it is alive |
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200 | G4Track * theTrack = theStep->GetTrack(); |
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201 | if(theTrack->GetTrackStatus()!=fAlive) { return; } |
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202 | |
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203 | // get region information |
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204 | G4StepPoint * thePrePoint = theStep->GetPreStepPoint(); |
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205 | G4LogicalVolume * thePreLV = thePrePoint->GetPhysicalVolume()->GetLogicalVolume(); |
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206 | RE01RegionInformation* thePreRInfo |
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207 | = (RE01RegionInformation*)(thePreLV->GetRegion()->GetUserInformation()); |
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208 | G4StepPoint * thePostPoint = theStep->GetPostStepPoint(); |
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209 | G4LogicalVolume * thePostLV = thePostPoint->GetPhysicalVolume()->GetLogicalVolume(); |
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210 | RE01RegionInformation* thePostRInfo |
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211 | = (RE01RegionInformation*)(thePostLV->GetRegion()->GetUserInformation()); |
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212 | |
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213 | // check if it is entering to the calorimeter volume |
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214 | if(!(thePreRInfo->IsCalorimeter()) && (thePostRInfo->IsCalorimeter())) |
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215 | { theTrack->SetTrackStatus(fSuspend); } |
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216 | } |
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217 | </pre> |
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218 | </td> |
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219 | </tr> |
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220 | <tr> |
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221 | <td align=center> |
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222 | Source listing 6.3.2<BR> |
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223 | <tt>Sample use of a region information class</tt> |
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224 | </td> |
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225 | </tr> |
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226 | </table></center> |
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227 | |
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228 | <BR><BR> |
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229 | <HR><A HREF="../../../../Authors/html/subjectsToAuthors.html"> |
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230 | <I>About the authors</A></I> </P></CENTER> |
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231 | |
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