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2 | <!-- Docbook Version: For Toolkit Developers Guide --> |
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3 | <!-- ******************************************************** --> |
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4 | |
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5 | <!-- ******************* Section (Level#1) ****************** --> |
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6 | <sect1 id="sect.DsgnFuncHitDig"> |
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7 | <title> |
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8 | Hits and Digitization |
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9 | </title> |
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10 | |
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11 | |
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12 | <!-- ******************* Section (Level#2) ****************** --> |
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13 | <sect2 id="sect.DsgnFuncHitDig.DsgPhlsp"> |
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14 | <title> |
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15 | Design Philosophy |
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16 | </title> |
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17 | |
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18 | <para> |
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19 | In Geant4 a <emphasis role="italic">hit</emphasis> is a snapshot of a |
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20 | physical interaction or an accumulation of interactions of a track or |
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21 | tracks in a ``sensitive'' detector component. A digitization, or |
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22 | <emphasis role="italic">digit</emphasis>, represents a detector output, |
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23 | such as an ADC/TDC count or a trigger signal. |
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24 | A <emphasis role="italic">digit</emphasis> is created from one or |
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25 | more hits and/or other <emphasis role="italic">digits</emphasis>. |
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26 | </para> |
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27 | |
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28 | <para> |
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29 | Given the wide variety of Geant4 applications, ways of describing detector |
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30 | sensitivity and the quantities to be stored in the |
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31 | <emphasis role="italic">hits</emphasis> and |
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32 | <emphasis role="italic">digits</emphasis> vary greatly. This category |
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33 | therefore provides only abstract classes for both detector sensitivity and |
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34 | <emphasis role="italic">hits</emphasis>/<emphasis role="italic">digits</emphasis>. |
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35 | It also provides tools for organizing the |
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36 | <emphasis role="italic">hits</emphasis>/<emphasis role="italic">digits</emphasis> |
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37 | into collections. |
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38 | </para> |
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39 | |
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40 | </sect2> |
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41 | |
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42 | <!-- ******************* Section (Level#2) ****************** --> |
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43 | <sect2 id="sect.DsgnFuncHitDig.ClassDsg"> |
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44 | <title> |
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45 | Class Design |
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46 | </title> |
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47 | |
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48 | <para> |
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49 | <itemizedlist spacing="compact"> |
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50 | <listitem><para> |
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51 | <emphasis role="bold">G4SensitiveDetectorManager</emphasis> - |
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52 | a list of G4SensitiveDetectors. |
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53 | </para></listitem> |
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54 | <listitem><para> |
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55 | <emphasis role="bold">G4HitsStructure</emphasis> - |
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56 | a tree-like structure of G4Hit collections. Each branch represents the |
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57 | hits in given sub-detector. For example, the first level of branches |
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58 | may consist of a tracker, ECAL, and HCAL, while the second level, in HCAL, |
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59 | consists of the barrel and endcaps. Finally the barrel may have phi-slices, |
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60 | Z-slices, etc. |
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61 | </para></listitem> |
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62 | <listitem><para> |
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63 | <emphasis role="bold">G4VSensitiveDetector</emphasis> - |
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64 | an abstract class of all of sensitive volumes. |
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65 | </para></listitem> |
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66 | <listitem><para> |
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67 | <emphasis role="bold">G4HitsCollection</emphasis> - |
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68 | a collection of hits. Instantiates an RWCollection class. |
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69 | </para></listitem> |
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70 | <listitem><para> |
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71 | <emphasis role="bold">G4VHit</emphasis> - |
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72 | this class has all the information about a particular hit caused by a |
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73 | single step. |
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74 | </para></listitem> |
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75 | <listitem><para> |
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76 | <emphasis role="bold">G4VDigitizer</emphasis> - |
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77 | the class of objects which transform the hits deposited by particles into |
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78 | digitizations. |
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79 | </para></listitem> |
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80 | <listitem><para> |
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81 | <emphasis role="bold">G4DigitizerManager</emphasis> - |
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82 | the (single) object dispatching common messages to individual digitizers. |
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83 | </para></listitem> |
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84 | <listitem><para> |
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85 | <emphasis role="bold">G4VDigi</emphasis> - |
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86 | an abstract (base) class for all G4 digitizations. This could be data as |
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87 | simple as a singe byte, or as complex as an Ntuple. |
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88 | </para></listitem> |
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89 | <listitem><para> |
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90 | <emphasis role="bold">G4DigiStructure</emphasis> - |
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91 | digitizations are organized as a structure, which could be anything |
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92 | between a single value and an Ntuple. |
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93 | </para></listitem> |
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94 | </itemizedlist> |
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95 | </para> |
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96 | |
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97 | <para> |
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98 | The object-oriented design of the 'hit' related classes is shown in the |
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99 | following class diagrams. The diagrams are described in the Booch notation. |
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100 | <xref linkend="fig.DsgnFuncHitDig_1" /> shows the general management of hit classes. |
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101 | <xref linkend="fig.DsgnFuncHitDig_2" /> shows the OO design of user-related hit classes. |
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102 | <xref linkend="fig.DsgnFuncHitDig_3" /> shows the OO design of the readout geometry. |
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103 | |
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104 | <figure id="fig.DsgnFuncHitDig_1"> |
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105 | <title> |
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106 | Overview of hit classes management |
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107 | </title> |
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108 | <mediaobject> |
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109 | <imageobject role="fo"> |
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110 | <imagedata |
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111 | fileref="./AllResources/OOAnalysisDesign/Hit/classDgmHitMain.jpg" format="JPG" contentwidth="10.0cm" align="center" /> |
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112 | </imageobject> |
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113 | <imageobject role="html"> |
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114 | <imagedata fileref="./AllResources/OOAnalysisDesign/Hit/classDgmHitMain.jpg" format="JPG" contentwidth="120%" align="center" /> |
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115 | </imageobject> |
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116 | </mediaobject> |
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117 | </figure> |
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118 | |
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119 | |
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120 | <figure id="fig.DsgnFuncHitDig_2"> |
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121 | <title> |
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122 | User hit classes |
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123 | </title> |
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124 | <mediaobject> |
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125 | <imageobject role="fo"> |
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126 | <imagedata |
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127 | fileref="./AllResources/OOAnalysisDesign/Hit/classDgmHitUser.jpg" format="JPG" |
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128 | contentwidth="10.0cm" align="center" /> |
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129 | </imageobject> |
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130 | <imageobject role="html"> |
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131 | <imagedata fileref="./AllResources/OOAnalysisDesign/Hit/classDgmHitUser.jpg" format="JPG" contentwidth="120%" align="center" /> |
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132 | </imageobject> |
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133 | </mediaobject> |
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134 | </figure> |
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135 | |
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136 | <figure id="fig.DsgnFuncHitDig_3"> |
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137 | <title> |
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138 | Readout geometry |
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139 | </title> |
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140 | <mediaobject> |
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141 | <imageobject role="fo"> |
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142 | <imagedata fileref="./AllResources/OOAnalysisDesign/Hit/classDgmReadoutGeom.jpg" format="JPG" contentwidth="10.0cm" align="center" /> |
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143 | </imageobject> |
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144 | <imageobject role="html"> |
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145 | <imagedata fileref="./AllResources/OOAnalysisDesign/Hit/classDgmReadoutGeom.jpg" format="JPG" contentwidth="120%" align="center" /> |
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146 | </imageobject> |
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147 | </mediaobject> |
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148 | </figure> |
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149 | </para> |
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150 | |
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151 | <!-- ******* Bridgehead ******* --> |
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152 | <bridgehead role="revisionHistory" renderas="sect4"> |
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153 | [Status of this chapter] |
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154 | </bridgehead> |
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155 | <para> |
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156 | <simplelist type="var"> |
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157 | <member> |
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158 | 27.06.05 section on design philosophy added (from Geant4 general paper) by |
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159 | D.H. Wright |
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160 | </member> |
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161 | <member> |
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162 | Dec. 2006 Conversion from latex to Docbook verson by K. Amako |
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163 | </member> |
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164 | </simplelist> |
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165 | </para> |
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166 | |
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167 | |
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168 | |
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169 | </sect2> |
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170 | </sect1> |
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