1 | <!-- ******************************************************** --> |
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2 | <!-- --> |
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3 | <!-- [History] --> |
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4 | <!-- Converted to DocBook: Katsuya Amako, Aug-2006 --> |
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5 | <!-- Changed by: Gabriele Cosmo, 18-Apr-2005 --> |
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6 | <!-- --> |
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7 | <!-- ******************************************************** --> |
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8 | |
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9 | |
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10 | <!-- ******************* Section (Level#2) ****************** --> |
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11 | <sect2 id="sect.Geom.PhysVol"> |
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12 | <title> |
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13 | Physical Volumes |
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14 | </title> |
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15 | |
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16 | <para> |
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17 | Physical volumes represent the spatial positioning of the |
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18 | volumes describing the detector elements. Several techniques can be |
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19 | used. They range from the simple placement of a single copy to the |
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20 | repeated positioning using either a simple linear formula or a user |
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21 | specified function. |
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22 | </para> |
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23 | |
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24 | <para> |
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25 | The simple placement involves the definition of a transformation |
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26 | matrix for the volume to be positioned. Repeated positioning is |
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27 | defined using the number of times a volume should be replicated at |
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28 | a given distance along a given direction. Finally it is possible to |
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29 | define a parameterised formula to specify the position of multiple |
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30 | copies of a volume. Details about these methods are given |
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31 | below. |
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32 | </para> |
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33 | |
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34 | <para> |
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35 | <emphasis role="bold">Note</emphasis> - For geometries which vary between runs and for |
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36 | which components of the old geometry setup are explicitely |
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37 | -deleted-, it is required to consider the proper order of deletion |
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38 | (which is the exact inverse of the actual construction, i.e., first |
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39 | delete physical volumes and then logical volumes). Deleting a |
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40 | logical volume does NOT delete its daughter volumes. |
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41 | </para> |
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42 | |
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43 | <para> |
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44 | It is not necessary to delete the geometry setup at the end of a |
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45 | job, the system will take care to free the volume and solid stores |
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46 | at the end of the job. The user has to take care of the deletion of |
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47 | any additional transformation or rotation matrices allocated |
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48 | dinamically in his/her own application. |
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49 | </para> |
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50 | |
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51 | <!-- ******************* Section (Level#3) ****************** --> |
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52 | <sect3 id="sect.Geom.PhysVol.PlaceSingle"> |
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53 | <title> |
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54 | Placements: single positioned copy |
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55 | </title> |
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56 | |
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57 | <para> |
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58 | In this case, the Physical Volume is created by associating a |
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59 | Logical Volume with a Rotation Matrix and a Translation vector. The |
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60 | Rotation Matrix represents the rotation of the reference frame of |
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61 | the considered volume relatively to its mother volume's reference |
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62 | frame. The Translation Vector represents the translation of the |
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63 | current volume in the reference frame of its mother volume. |
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64 | </para> |
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65 | |
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66 | <para> |
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67 | Transformations including reflections are not allowed. |
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68 | </para> |
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69 | |
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70 | <para> |
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71 | To create a Placement one must construct it using: |
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72 | |
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73 | <informalexample> |
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74 | <programlisting> |
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75 | G4PVPlacement( G4RotationMatrix* pRot, |
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76 | const G4ThreeVector& tlate, |
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77 | G4LogicalVolume* pCurrentLogical, |
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78 | const G4String& pName, |
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79 | G4LogicalVolume* pMotherLogical, |
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80 | G4bool pMany, |
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81 | G4int pCopyNo, |
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82 | G4bool pSurfChk=false ) |
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83 | </programlisting> |
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84 | </informalexample> |
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85 | |
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86 | where: |
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87 | |
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88 | <informaltable> |
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89 | <tgroup cols="2"> |
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90 | <tbody> |
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91 | <row> |
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92 | <entry> |
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93 | <literal>pRot</literal> |
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94 | </entry> |
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95 | <entry> |
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96 | Rotation with respect to its mother volume |
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97 | </entry> |
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98 | </row> |
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99 | <row> |
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100 | <entry> |
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101 | <literal>tlate</literal> |
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102 | </entry> |
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103 | <entry> |
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104 | Translation with respect to its mother volume |
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105 | </entry> |
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106 | </row> |
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107 | <row> |
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108 | <entry> |
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109 | <literal>pCurrentLogical</literal> |
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110 | </entry> |
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111 | <entry> |
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112 | The associated Logical Volume |
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113 | </entry> |
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114 | </row> |
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115 | <row> |
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116 | <entry> |
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117 | <literal>pName</literal> |
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118 | </entry> |
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119 | <entry> |
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120 | String identifier for this placement |
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121 | </entry> |
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122 | </row> |
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123 | <row> |
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124 | <entry> |
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125 | <literal>pMotherLogical</literal> |
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126 | </entry> |
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127 | <entry> |
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128 | The associated mother volume |
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129 | </entry> |
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130 | </row> |
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131 | <row> |
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132 | <entry> |
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133 | <literal>pMany</literal> |
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134 | </entry> |
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135 | <entry> |
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136 | For future use. Can be set to false |
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137 | </entry> |
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138 | </row> |
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139 | <row> |
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140 | <entry> |
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141 | <literal>pCopyNo</literal> |
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142 | </entry> |
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143 | <entry> |
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144 | Integer which identifies this placement |
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145 | </entry> |
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146 | </row> |
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147 | <row> |
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148 | <entry> |
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149 | <literal>pSurfChk</literal> |
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150 | </entry> |
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151 | <entry> |
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152 | if true activates check for overlaps with existing volumes |
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153 | </entry> |
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154 | </row> |
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155 | </tbody> |
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156 | </tgroup> |
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157 | </informaltable> |
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158 | </para> |
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159 | |
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160 | <para> |
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161 | Care must be taken because the rotation matrix is not copied by |
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162 | a <literal>G4PVPlacement</literal>. So the user must not modify it after |
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163 | creating a Placement that uses it. However the same rotation matrix |
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164 | can be re-used for many volumes. |
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165 | </para> |
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166 | |
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167 | <para> |
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168 | Currently Boolean operations are not implemented at the level of |
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169 | physical volume. So <literal>pMany</literal> must be false. However, an |
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170 | alternative implementation of Boolean operations exists. In this |
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171 | approach a solid can be created from the union, intersection or |
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172 | subtraction of two solids. See <xref linkend="sect.Geom.Solids.BoolOp" /> |
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173 | above for an explanation of this. |
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174 | </para> |
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175 | |
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176 | <para> |
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177 | The mother volume must be specified for all volumes |
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178 | <emphasis>except</emphasis> the world volume. |
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179 | </para> |
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180 | |
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181 | <para> |
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182 | An alternative way to specify a Placement utilizes a different |
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183 | method to place the volume. The solid itself is moved by rotating |
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184 | and translating it to bring it into the system of coordinates of |
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185 | the mother volume. This <emphasis>active</emphasis> method can be utilized using |
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186 | the following constructor: |
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187 | |
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188 | <informalexample> |
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189 | <programlisting> |
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190 | G4PVPlacement( G4Transform3D solidTransform, |
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191 | G4LogicalVolume* pCurrentLogical, |
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192 | const G4String& pName, |
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193 | G4LogicalVolume* pMotherLogical, |
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194 | G4bool pMany, |
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195 | G4int pCopyNo, |
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196 | G4bool pSurfChk=false ) |
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197 | </programlisting> |
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198 | </informalexample> |
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199 | </para> |
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200 | |
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201 | <para> |
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202 | An alternative method to specify the mother volume is to specify |
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203 | its placed physical volume. It can be used in either of the above |
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204 | methods of specifying the placement's position and rotation. The |
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205 | effect will be exactly the same as for using the mother logical |
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206 | volume. |
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207 | </para> |
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208 | |
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209 | <para> |
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210 | Note that a Placement Volume can still represent multiple |
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211 | detector elements. This can happen if several copies exist of the |
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212 | mother logical volume. Then different detector elements will belong |
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213 | to different branches of the tree of the hierarchy of geometrical |
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214 | volumes. |
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215 | </para> |
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216 | |
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217 | </sect3> |
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218 | |
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219 | <!-- ******************* Section (Level#3) ****************** --> |
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220 | <sect3 id="sect.Geom.PhysVol.RepeatVol"> |
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221 | <title> |
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222 | Repeated volumes |
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223 | </title> |
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224 | |
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225 | <para> |
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226 | In this case, a single Physical Volume represents multiple copies |
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227 | of a volume within its mother volume, allowing to save memory. This |
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228 | is normally done when the volumes to be positioned follow a well |
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229 | defined rotational or translational symmetry along a Cartesian or |
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230 | cylindrical coordinate. The Repeated Volumes technique is available |
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231 | for volumes described by CSG solids. |
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232 | </para> |
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233 | |
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234 | <!-- ******* Bridgehead ******* --> |
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235 | <bridgehead renderas='sect4'> |
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236 | Replicas: |
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237 | </bridgehead> |
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238 | |
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239 | <para> |
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240 | Replicas are <emphasis>repeated volumes</emphasis> in the case when the |
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241 | multiple copies of the volume are all identical. The coordinate |
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242 | axis and the number of replicas need to be specified for the |
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243 | program to compute at run time the transformation matrix |
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244 | corresponding to each copy. |
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245 | |
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246 | <informalexample> |
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247 | <programlisting> |
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248 | G4PVReplica( const G4String& pName, |
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249 | G4LogicalVolume* pCurrentLogical, |
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250 | G4LogicalVolume* pMotherLogical, // OR G4VPhysicalVolume* |
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251 | const EAxis pAxis, |
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252 | const G4int nReplicas, |
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253 | const G4double width, |
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254 | const G4double offset=0 ) |
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255 | </programlisting> |
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256 | </informalexample> |
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257 | |
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258 | where: |
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259 | |
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260 | <informaltable> |
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261 | <tgroup cols="2"> |
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262 | <tbody> |
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263 | <row> |
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264 | <entry> |
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265 | <literal>pName</literal> |
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266 | </entry> |
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267 | <entry> |
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268 | String identifier for the replicated volume |
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269 | </entry> |
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270 | </row> |
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271 | <row> |
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272 | <entry> |
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273 | <literal>pCurrentLogical</literal> |
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274 | </entry> |
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275 | <entry> |
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276 | The associated Logical Volume |
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277 | </entry> |
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278 | </row> |
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279 | <row> |
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280 | <entry> |
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281 | <literal>pMotherLogical</literal> |
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282 | </entry> |
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283 | <entry> |
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284 | The associated mother volume |
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285 | </entry> |
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286 | </row> |
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287 | <row> |
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288 | <entry> |
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289 | <literal>pAxis</literal> |
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290 | </entry> |
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291 | <entry> |
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292 | The axis along with the replication is applied |
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293 | </entry> |
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294 | </row> |
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295 | <row> |
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296 | <entry> |
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297 | <literal>nReplicas</literal> |
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298 | </entry> |
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299 | <entry> |
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300 | The number of replicated volumes |
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301 | </entry> |
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302 | </row> |
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303 | <row> |
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304 | <entry> |
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305 | <literal>width</literal> |
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306 | </entry> |
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307 | <entry> |
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308 | The width of a single replica along the axis of replication |
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309 | </entry> |
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310 | </row> |
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311 | <row> |
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312 | <entry> |
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313 | <literal>offset</literal> |
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314 | </entry> |
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315 | <entry> |
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316 | Possible offset associated to mother offset along the axis of |
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317 | replication |
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318 | </entry> |
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319 | </row> |
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320 | </tbody> |
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321 | </tgroup> |
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322 | </informaltable> |
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323 | </para> |
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324 | |
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325 | <para> |
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326 | <literal>G4PVReplica</literal> represents <literal>nReplicas</literal> volumes |
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327 | differing only in their positioning, and completely <emphasis role="bold">filling</emphasis> |
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328 | the containing mother volume. Consequently if a |
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329 | <literal>G4PVReplica</literal> is 'positioned' inside a given mother it |
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330 | <emphasis role="bold">MUST</emphasis> be the mother's only daughter volume. Replica's |
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331 | correspond to divisions or slices that completely fill the mother |
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332 | volume and have no offsets. For Cartesian axes, slices are |
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333 | considered perpendicular to the axis of replication. |
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334 | </para> |
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335 | |
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336 | <para> |
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337 | The replica's positions are calculated by means of a linear |
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338 | formula. Replication may occur along: |
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339 | |
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340 | <itemizedlist spacing="compact"> |
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341 | <listitem><para> |
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342 | <emphasis>Cartesian axes <literal>(kXAxis,kYAxis,kZAxis)</literal></emphasis> |
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343 | <para> |
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344 | The replications, of specified width have coordinates of form |
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345 | <literal>(-width*(nReplicas-1)*0.5+n*width,0,0)</literal> |
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346 | </para> |
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347 | <para> |
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348 | where <literal>n=0.. nReplicas-1</literal> for the case of <literal>kXAxis</literal>, |
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349 | and are unrotated. |
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350 | </para> |
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351 | </para></listitem> |
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352 | <listitem><para> |
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353 | <emphasis>Radial axis (cylindrical polar) <literal>(kRho)</literal></emphasis> |
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354 | <para> |
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355 | The replications are cons/tubs sections, centred on the origin and |
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356 | are unrotated. |
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357 | </para> |
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358 | <para> |
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359 | They have radii of <literal>width*n+offset</literal> to |
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360 | <literal>width*(n+1)+offset</literal> where |
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361 | <literal>n=0..nReplicas-1</literal> |
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362 | </para> |
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363 | </para></listitem> |
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364 | <listitem><para> |
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365 | <emphasis>Phi axis (cylindrical polar) <literal>(kPhi)</literal></emphasis> |
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366 | <para> |
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367 | The replications are <emphasis>phi sections</emphasis> or |
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368 | <emphasis>wedges</emphasis>, and of cons/tubs form. |
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369 | </para> |
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370 | <para> |
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371 | They have <literal>phi</literal> of <literal>offset+n*width</literal> to |
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372 | <literal>offset+(n+1)*width</literal> where |
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373 | <literal>n=0..nReplicas-1</literal> |
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374 | </para> |
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375 | </para></listitem> |
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376 | </itemizedlist> |
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377 | </para> |
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378 | |
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379 | <para> |
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380 | The coordinate system of the replicas is at the centre of each |
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381 | replica for the cartesian axis. For the radial case, the coordinate |
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382 | system is unchanged from the mother. For the <literal>phi</literal> axis, the |
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383 | new coordinate system is rotated such that the X axis bisects the |
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384 | angle made by each wedge, and Z remains parallel to the mother's Z |
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385 | axis. |
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386 | </para> |
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387 | |
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388 | <para> |
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389 | The solid associated via the replicas' logical volume should |
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390 | have the dimensions of the first volume created and must be of the |
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391 | correct symmetry/type, in order to assist in good |
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392 | visualisation. |
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393 | </para> |
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394 | |
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395 | <para> |
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396 | ex. For X axis replicas in a box, the solid should be another box |
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397 | with the dimensions of the replications. (same Y & Z dimensions |
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398 | as mother box, X dimension = mother's X dimension/nReplicas). |
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399 | </para> |
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400 | |
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401 | <para> |
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402 | Replicas may be placed inside other replicas, provided the above |
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403 | rule is observed. Normal placement volumes may be placed inside |
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404 | replicas, provided that they do not intersect the mother's or any |
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405 | previous replica's boundaries. Parameterised volumes may not be |
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406 | placed inside. |
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407 | </para> |
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408 | |
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409 | <para> |
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410 | Because of these rules, it is not possible to place any other |
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411 | volume inside a replication in <literal>radius</literal>. |
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412 | </para> |
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413 | |
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414 | <para> |
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415 | The world volume <emphasis>cannot</emphasis> act as a replica, therefore it |
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416 | cannot be sliced. |
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417 | </para> |
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418 | |
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419 | <para> |
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420 | During tracking, the translation + rotation associated with each |
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421 | <literal>G4PVReplica</literal> object is modified according to the currently |
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422 | 'active' replication. The solid is not modified and consequently |
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423 | has the wrong parameters for the cases of <literal>phi</literal> and |
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424 | <literal>r</literal> replication and for when the cross-section of the mother |
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425 | is not constant along the replication. |
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426 | </para> |
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427 | |
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428 | <para> |
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429 | Example: |
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430 | |
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431 | <example id="programlist_Geom.PhysVol_1"> |
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432 | <title> |
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433 | An example of simple replicated volumes with <literal>G4PVReplica</literal>. |
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434 | </title> |
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435 | <programlisting> |
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436 | G4PVReplica repX("Linear Array", |
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437 | pRepLogical, |
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438 | pContainingMother, |
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439 | kXAxis, 5, 10*mm); |
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440 | |
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441 | G4PVReplica repR("RSlices", |
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442 | pRepRLogical, |
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443 | pContainingMother, |
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444 | kRho, 5, 10*mm, 0); |
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445 | |
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446 | G4PVReplica repRZ("RZSlices", |
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447 | pRepRZLogical, |
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448 | &repR, |
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449 | kZAxis, 5, 10*mm); |
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450 | |
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451 | G4PVReplica repRZPhi("RZPhiSlices", |
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452 | pRepRZPhiLogical, |
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453 | &repRZ, |
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454 | kPhi, 4, M_PI*0.5*rad, 0); |
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455 | </programlisting> |
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456 | </example> |
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457 | </para> |
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458 | |
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459 | <para> |
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460 | <literal>RepX</literal> is an array of 5 replicas of width 10*mm, |
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461 | positioned inside and completely filling the volume pointed by |
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462 | <literal>pContainingMother</literal>. The mother's X length must be |
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463 | 5*10*mm=50*mm (for example, if the mother's solid were a Box of |
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464 | half lengths [25,25,25] then the replica's solid must be a box of |
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465 | half lengths [25,25,5]). |
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466 | </para> |
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467 | |
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468 | <para> |
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469 | If the containing mother's solid is a tube of radius 50*mm and |
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470 | half Z length of 25*mm, <literal>RepR</literal> divides the mother tube into |
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471 | 5 cylinders (hence the solid associated with <literal>pRepRLogical</literal> |
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472 | must be a tube of radius 10*mm, and half Z length 25*mm); |
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473 | <literal>repRZ</literal> divides it into 5 shorter cylinders (the solid |
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474 | associated with <literal>pRepRZLogical</literal> must be a tube of radius |
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475 | 10*mm, and half Z length 5*mm); finally, <literal>repRZPhi</literal> divides |
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476 | it into 4 tube segments with full angle of 90 degrees (the solid |
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477 | associated with <literal>pRepRZPhiLogical</literal> must be a tube segment of |
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478 | radius 10*mm, half Z length 5*mm and delta phi of |
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479 | M_PI*0.5*rad). |
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480 | </para> |
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481 | |
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482 | <para> |
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483 | No further volumes may be placed inside these replicas. To do so |
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484 | would result in intersecting boundaries due to the <literal>r</literal> |
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485 | replications. |
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486 | </para> |
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487 | |
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488 | <!-- ******* Bridgehead ******* --> |
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489 | <bridgehead renderas='sect4'> |
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490 | Parameterised Volumes: |
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491 | </bridgehead> |
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492 | |
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493 | <para> |
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494 | Parameterised Volumes are <emphasis>repeated volumes</emphasis> in the case in |
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495 | which the multiple copies of a volume can be different in size, |
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496 | solid type, or material. The solid's type, its dimensions, the |
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497 | material and the transformation matrix can all be parameterised in |
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498 | function of the copy number, both when a strong symmetry exist and |
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499 | when it does not. The user implements the desired parameterisation |
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500 | function and the program computes and updates automatically at run |
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501 | time the information associated to the Physical Volume. |
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502 | </para> |
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503 | |
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504 | <para> |
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505 | An example of creating a parameterised volume (by dimension and |
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506 | position) exists in novice example N02. The implementation is |
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507 | provided in the two classes <literal>ExN02DetectorConstruction</literal> and |
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508 | <literal>ExN02ChamberParameterisation</literal>. |
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509 | </para> |
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510 | |
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511 | <para> |
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512 | To create a parameterised volume, one must first create its |
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513 | logical volume like <literal>trackerChamberLV</literal> below. Then one must |
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514 | create his own parameterisation class |
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515 | (<emphasis>ExN02ChamberParameterisation</emphasis>) and instantiate an object of |
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516 | this class (<literal>chamberParam</literal>). We will see how to create the |
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517 | parameterisation below. |
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518 | |
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519 | <example id="programlist_Geom.PhysVol_2"> |
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520 | <title> |
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521 | An example of Parameterised volumes. |
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522 | </title> |
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523 | <programlisting> |
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524 | //------------------------------ |
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525 | // Tracker segments |
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526 | //------------------------------ |
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527 | // An example of Parameterised volumes |
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528 | // dummy values for G4Box -- modified by parameterised volume |
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529 | G4VSolid * solidChamber = |
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530 | new G4Box("chamberBox", 10.*cm, 10.*cm, 10.*cm); |
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531 | |
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532 | G4LogicalVolume * trackerChamberLV |
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533 | = new G4LogicalVolume(solidChamber, Aluminum, "trackerChamberLV"); |
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534 | G4VPVParameterisation * chamberParam |
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535 | = new ExN02ChamberParameterisation( |
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536 | 6, // NoChambers, |
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537 | -240.*cm, // Z of centre of first |
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538 | 80*cm, // Z spacing of centres |
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539 | 20*cm, // Width Chamber, |
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540 | 50*cm, // lengthInitial, |
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541 | trackerSize*2.); // lengthFinal |
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542 | |
---|
543 | G4VPhysicalVolume *trackerChamber_phys |
---|
544 | = new G4PVParameterised("TrackerChamber_parameterisedPV", |
---|
545 | trackerChamberLV, // Its logical volume |
---|
546 | logicTracker, // Mother logical volume |
---|
547 | kUndefined, // Allow default voxelising -- no axis |
---|
548 | 6, // Number of chambers |
---|
549 | chamberParam); // The parameterisation |
---|
550 | // "kUndefined" is the suggested choice, giving 3D voxelisation (i.e. along the three |
---|
551 | // cartesian axes, as is applied for placements. |
---|
552 | // |
---|
553 | // Note: In some cases where volume have clear separation along a single axis, |
---|
554 | // this axis (eg kZAxis) can be used to choose (force) optimisation only along |
---|
555 | // this axis in geometrical calculations. |
---|
556 | // When an axis is given it forces the use of one-dimensional voxelisation. |
---|
557 | </programlisting> |
---|
558 | </example> |
---|
559 | </para> |
---|
560 | |
---|
561 | <para> |
---|
562 | The general constructor is: |
---|
563 | |
---|
564 | <informalexample> |
---|
565 | <programlisting> |
---|
566 | G4PVParameterised( const G4String& pName, |
---|
567 | G4LogicalVolume* pCurrentLogical, |
---|
568 | G4LogicalVolume* pMotherLogical, // OR G4VPhysicalVolume* |
---|
569 | const EAxis pAxis, |
---|
570 | const G4int nReplicas, |
---|
571 | G4VPVParameterisation* pParam, |
---|
572 | G4bool pSurfChk=false ) |
---|
573 | |
---|
574 | </programlisting> |
---|
575 | </informalexample> |
---|
576 | </para> |
---|
577 | |
---|
578 | <para> |
---|
579 | Note that for a parameterised volume the user must always |
---|
580 | specify a mother volume. So the world volume can <emphasis>never</emphasis> be a |
---|
581 | parameterised volume, nor it can be sliced. The mother volume can |
---|
582 | be specified either as a physical or a logical volume. |
---|
583 | </para> |
---|
584 | |
---|
585 | <para> |
---|
586 | <literal>pAxis</literal> specifies the tracking optimisation algorithm to |
---|
587 | apply: if a valid axis (the axis along which the parameterisation |
---|
588 | is performed) is specified, a simple one-dimensional voxelisation |
---|
589 | algorithm is applied; if "kUndefined" is specified instead, the |
---|
590 | default three-dimensional voxelisation algorithm applied for normal |
---|
591 | placements will be activated. In the latter case, more voxels will |
---|
592 | be generated, therefore a greater amount of memory will be consumed |
---|
593 | by the optimisation algorithm. |
---|
594 | </para> |
---|
595 | |
---|
596 | <para> |
---|
597 | <literal>pSurfChk</literal> if <literal>true</literal> activates a check for |
---|
598 | overlaps with existing volumes or paramaterised instances. |
---|
599 | </para> |
---|
600 | |
---|
601 | <para> |
---|
602 | The parameterisation mechanism associated to a parameterised |
---|
603 | volume is defined in the parameterisation class and its methods. |
---|
604 | Every parameterisation must create two methods: |
---|
605 | |
---|
606 | <itemizedlist spacing="compact"> |
---|
607 | <listitem><para> |
---|
608 | <literal>ComputeTransformation</literal> defines where one of the copies |
---|
609 | is placed, |
---|
610 | </para></listitem> |
---|
611 | <listitem><para> |
---|
612 | <literal>ComputeDimensions</literal> defines the size of one copy, and |
---|
613 | </para></listitem> |
---|
614 | <listitem><para> |
---|
615 | a constructor that initializes any member variables that are |
---|
616 | required. |
---|
617 | </para></listitem> |
---|
618 | </itemizedlist> |
---|
619 | |
---|
620 | <para> |
---|
621 | An example is <literal>ExN02ChamberParameterisation</literal> that |
---|
622 | parameterises a series of boxes of different sizes |
---|
623 | |
---|
624 | <example id="programlist_Geom.PhysVol_3"> |
---|
625 | <title> |
---|
626 | An example of Parameterised boxes of different sizes. |
---|
627 | </title> |
---|
628 | <programlisting> |
---|
629 | class ExN02ChamberParameterisation : public G4VPVParameterisation |
---|
630 | { |
---|
631 | ... |
---|
632 | void ComputeTransformation(const G4int copyNo, |
---|
633 | G4VPhysicalVolume *physVol) const; |
---|
634 | |
---|
635 | void ComputeDimensions(G4Box& trackerLayer, |
---|
636 | const G4int copyNo, |
---|
637 | const G4VPhysicalVolume *physVol) const; |
---|
638 | ... |
---|
639 | } |
---|
640 | </programlisting> |
---|
641 | </example> |
---|
642 | </para> |
---|
643 | |
---|
644 | <para> |
---|
645 | These methods works as follows: |
---|
646 | </para> |
---|
647 | |
---|
648 | <para> |
---|
649 | The <literal>ComputeTransformation</literal> method is called with a copy |
---|
650 | number for the instance of the parameterisation under |
---|
651 | consideration. It must compute the transformation for this copy, |
---|
652 | and set the physical volume to utilize this transformation: |
---|
653 | |
---|
654 | <informalexample> |
---|
655 | <programlisting> |
---|
656 | void ExN02ChamberParameterisation::ComputeTransformation |
---|
657 | (const G4int copyNo,G4VPhysicalVolume *physVol) const |
---|
658 | { |
---|
659 | G4double Zposition= fStartZ + copyNo * fSpacing; |
---|
660 | G4ThreeVector origin(0,0,Zposition); |
---|
661 | physVol->SetTranslation(origin); |
---|
662 | physVol->SetRotation(0); |
---|
663 | } |
---|
664 | </programlisting> |
---|
665 | </informalexample> |
---|
666 | </para> |
---|
667 | |
---|
668 | <para> |
---|
669 | Note that the translation and rotation given in this scheme are |
---|
670 | those for the frame of coordinates (the <emphasis>passive</emphasis> method). |
---|
671 | They are <emphasis role="bold">not</emphasis> for the |
---|
672 | <emphasis>active</emphasis> method, in which the |
---|
673 | solid is rotated into the mother frame of coordinates. |
---|
674 | </para> |
---|
675 | |
---|
676 | <para> |
---|
677 | Similarly the <literal>ComputeDimensions</literal> method is used to set |
---|
678 | the size of that copy. |
---|
679 | |
---|
680 | <informalexample> |
---|
681 | <programlisting> |
---|
682 | void ExN02ChamberParameterisation::ComputeDimensions |
---|
683 | (G4Box & trackerChamber, const G4int copyNo, |
---|
684 | const G4VPhysicalVolume * physVol) const |
---|
685 | { |
---|
686 | G4double halfLength= fHalfLengthFirst + (copyNo-1) * fHalfLengthIncr; |
---|
687 | trackerChamber.SetXHalfLength(halfLength); |
---|
688 | trackerChamber.SetYHalfLength(halfLength); |
---|
689 | trackerChamber.SetZHalfLength(fHalfWidth); |
---|
690 | } |
---|
691 | </programlisting> |
---|
692 | </informalexample> |
---|
693 | </para> |
---|
694 | |
---|
695 | <para> |
---|
696 | The user must ensure that the type of the first argument of this |
---|
697 | method (in this example <literal>G4Box &</literal>) corresponds to the |
---|
698 | type of object the user give to the logical volume of parameterised |
---|
699 | physical volume. |
---|
700 | </para> |
---|
701 | |
---|
702 | <para> |
---|
703 | More advanced usage allows the user: |
---|
704 | |
---|
705 | <itemizedlist spacing="compact"> |
---|
706 | <listitem><para> |
---|
707 | to change the type of solid by creating a <literal>ComputeSolid</literal> |
---|
708 | method, or |
---|
709 | </para></listitem> |
---|
710 | <listitem><para> |
---|
711 | to change the material of the volume by creating a |
---|
712 | <literal>ComputeMaterial</literal> method. This method can also utilise |
---|
713 | information from a parent or other ancestor volume (see the Nested |
---|
714 | Parameterisation below.) |
---|
715 | </para></listitem> |
---|
716 | </itemizedlist> |
---|
717 | |
---|
718 | for the parameterisation. |
---|
719 | </para> |
---|
720 | |
---|
721 | <para> |
---|
722 | Example N07 shows a simple parameterisation by material. A more |
---|
723 | complex example is provided in |
---|
724 | <literal>examples/extended/medical/DICOM</literal>, where a phantom grid of |
---|
725 | cells is built using a parameterisation by material defined through |
---|
726 | a map. |
---|
727 | </para> |
---|
728 | |
---|
729 | <note> |
---|
730 | <title>Note</title> |
---|
731 | <para> |
---|
732 | Currently for many cases it is not possible to add |
---|
733 | daughter volumes to a parameterised volume. Only parameterised |
---|
734 | volumes all of whose solids have the same size are allowed to |
---|
735 | contain daughter volumes. When the size or type of solid varies, |
---|
736 | adding daughters is not supported. |
---|
737 | So the full power of parameterised volumes can be used only for |
---|
738 | "leaf" volumes, which contain no other volumes. |
---|
739 | </para> |
---|
740 | <para> |
---|
741 | A hierarchy of volumes included in a parameterised volume cannot |
---|
742 | vary. Therefore, it is not possible to implement a parameterisation |
---|
743 | which can modify the hierachy of volumes included inside a specific |
---|
744 | parameterised copy. |
---|
745 | </para> |
---|
746 | </note> |
---|
747 | |
---|
748 | |
---|
749 | <!-- ******* Bridgehead ******* --> |
---|
750 | <bridgehead renderas='sect4'> |
---|
751 | Advanced parameterisations for 'nested' parameterised volumes |
---|
752 | </bridgehead> |
---|
753 | |
---|
754 | <para> |
---|
755 | A new type of parameterisation enables a user to have the |
---|
756 | daughter's material also depend on the copy number of the parent |
---|
757 | when a parameterised volume (daughter) is located inside another |
---|
758 | (parent) repeated volume. The parent volume can be a replica, a |
---|
759 | parameterised volume, or a division if the key feature of modifying |
---|
760 | its contents is utilised. (Note: a 'nested' parameterisation inside |
---|
761 | a placement volume is not supported, because all copies of a |
---|
762 | placement volume must be identical at all levels.) |
---|
763 | </para> |
---|
764 | |
---|
765 | <para> |
---|
766 | In such a " nested" parameterisation , the user must provide a |
---|
767 | <literal>ComputeMaterial</literal> method that utilises the new argument that |
---|
768 | represents the touchable history of the parent volume: |
---|
769 | |
---|
770 | <informalexample> |
---|
771 | <programlisting> |
---|
772 | // Sample Parameterisation |
---|
773 | class SampleNestedParameterisation : public G4VNestedParameterisation |
---|
774 | { |
---|
775 | public: |
---|
776 | // .. other methods ... |
---|
777 | // Mandatory method, required and reason for this class |
---|
778 | virtual G4Material* ComputeMaterial(G4VPhysicalVolume *currentVol, |
---|
779 | const G4int no_lev, |
---|
780 | const G4VTouchable *parentTouch); |
---|
781 | private: |
---|
782 | G4Material *material1, *material2; |
---|
783 | }; |
---|
784 | </programlisting> |
---|
785 | </informalexample> |
---|
786 | </para> |
---|
787 | |
---|
788 | <para> |
---|
789 | The implementation of the method can utilise any information |
---|
790 | from a parent or other ancestor volume of its parameterised |
---|
791 | physical volume, but typically it will use only the copy |
---|
792 | number: |
---|
793 | |
---|
794 | <informalexample> |
---|
795 | <programlisting> |
---|
796 | G4Material* |
---|
797 | SampleNestedParameterisation::ComputeMaterial(G4VPhysicalVolume *currentVol, |
---|
798 | const G4int no_lev, |
---|
799 | const G4VTouchable *parentTouchable) |
---|
800 | { |
---|
801 | G4Material *material=0; |
---|
802 | |
---|
803 | // Get the information about the parent volume |
---|
804 | G4int no_parent= parentTouchable->GetReplicaNumber(); |
---|
805 | G4int no_total= no_parent + no_lev; |
---|
806 | // A simple 'checkerboard' pattern of two materials |
---|
807 | if( no_total / 2 == 1 ) material= material1; |
---|
808 | else material= material2; |
---|
809 | // Set the material to the current logical volume |
---|
810 | G4LogicalVolume* currentLogVol= currentVol->GetLogicalVolume(); |
---|
811 | currentLogVol->SetMaterial( material ); |
---|
812 | return material; |
---|
813 | } |
---|
814 | </programlisting> |
---|
815 | </informalexample> |
---|
816 | </para> |
---|
817 | |
---|
818 | <para> |
---|
819 | Nested parameterisations are suitable for the case of regular, |
---|
820 | 'voxel' geometries in which a large number of 'equal' volumes are |
---|
821 | required, and their only difference is in their material. By |
---|
822 | creating two (or more) levels of parameterised physical volumes it |
---|
823 | is possible to divide space, while requiring only limited |
---|
824 | additional memory for very fine-level optimisation. This provides |
---|
825 | fast navigation. Alternative implementations, taking into account |
---|
826 | the regular structure of such geometries in navigation are under |
---|
827 | study. |
---|
828 | </para> |
---|
829 | |
---|
830 | <!-- ******* Bridgehead ******* --> |
---|
831 | <bridgehead renderas='sect4'> |
---|
832 | Divisions of Volumes |
---|
833 | </bridgehead> |
---|
834 | |
---|
835 | <para> |
---|
836 | Divisions in Geant4 are implemented as a specialized type of |
---|
837 | parameterised volumes. |
---|
838 | </para> |
---|
839 | |
---|
840 | <para> |
---|
841 | They serve to divide a volume into identical copies along one of |
---|
842 | its axes, providing the possibility to define an <emphasis>offset</emphasis>, and |
---|
843 | without the limitation that the daugthers have to fill the mother |
---|
844 | volume as it is the case for the replicas. In the case, for |
---|
845 | example, of a tube divided along its radial axis, the copies are |
---|
846 | not strictly identical, but have increasing radii, although their |
---|
847 | widths are constant. |
---|
848 | </para> |
---|
849 | |
---|
850 | <para> |
---|
851 | To divide a volume it will be necessary to provide: |
---|
852 | |
---|
853 | <orderedlist spacing="compact"> |
---|
854 | <listitem><para> |
---|
855 | the axis of division, and |
---|
856 | </para></listitem> |
---|
857 | <listitem><para> |
---|
858 | either |
---|
859 | <itemizedlist spacing="compact"> |
---|
860 | <listitem><para> |
---|
861 | the number of divisions (so that the width of each division |
---|
862 | will be automatically calculated), or |
---|
863 | </para></listitem> |
---|
864 | <listitem><para> |
---|
865 | the division width (so that the number of divisions will be |
---|
866 | automatically calculated to fill as much of the mother as |
---|
867 | possible), or |
---|
868 | </para></listitem> |
---|
869 | <listitem><para> |
---|
870 | both the number of divisions and the division width (this is |
---|
871 | especially designed for the case where the copies do not fully fill |
---|
872 | the mother). |
---|
873 | </para></listitem> |
---|
874 | </itemizedlist> |
---|
875 | </para></listitem> |
---|
876 | </orderedlist> |
---|
877 | </para> |
---|
878 | |
---|
879 | <para> |
---|
880 | An <emphasis>offset</emphasis> can be defined so that the first copy will |
---|
881 | start at some distance from the mother wall. The dividing copies |
---|
882 | will be then distributed to occupy the rest of the volume. |
---|
883 | </para> |
---|
884 | |
---|
885 | <para> |
---|
886 | There are three constructors, corresponding to the three input |
---|
887 | possibilities described above: |
---|
888 | |
---|
889 | <itemizedlist spacing="compact"> |
---|
890 | <listitem><para> |
---|
891 | Giving only the number of divisions: |
---|
892 | |
---|
893 | <informalexample> |
---|
894 | <programlisting> |
---|
895 | G4PVDivision( const G4String& pName, |
---|
896 | G4LogicalVolume* pCurrentLogical, |
---|
897 | G4LogicalVolume* pMotherLogical, |
---|
898 | const EAxis pAxis, |
---|
899 | const G4int nDivisions, |
---|
900 | const G4double offset ) |
---|
901 | </programlisting> |
---|
902 | </informalexample> |
---|
903 | </para></listitem> |
---|
904 | <listitem><para> |
---|
905 | Giving only the division width: |
---|
906 | |
---|
907 | <informalexample> |
---|
908 | <programlisting> |
---|
909 | G4PVDivision( const G4String& pName, |
---|
910 | G4LogicalVolume* pCurrentLogical, |
---|
911 | G4LogicalVolume* pMotherLogical, |
---|
912 | const EAxis pAxis, |
---|
913 | const G4double width, |
---|
914 | const G4double offset ) |
---|
915 | </programlisting> |
---|
916 | </informalexample> |
---|
917 | </para></listitem> |
---|
918 | <listitem><para> |
---|
919 | Giving the number of divisions and the division width: |
---|
920 | |
---|
921 | <informalexample> |
---|
922 | <programlisting> |
---|
923 | G4PVDivision( const G4String& pName, |
---|
924 | G4LogicalVolume* pCurrentLogical, |
---|
925 | G4LogicalVolume* pMotherLogical, |
---|
926 | const EAxis pAxis, |
---|
927 | const G4int nDivisions, |
---|
928 | const G4double width, |
---|
929 | const G4double offset ) |
---|
930 | </programlisting> |
---|
931 | </informalexample> |
---|
932 | </para></listitem> |
---|
933 | </itemizedlist> |
---|
934 | |
---|
935 | where: |
---|
936 | |
---|
937 | <informaltable> |
---|
938 | <tgroup cols="2"> |
---|
939 | <tbody> |
---|
940 | <row> |
---|
941 | <entry> |
---|
942 | <literal>pName</literal> |
---|
943 | </entry> |
---|
944 | <entry> |
---|
945 | String identifier for the replicated volume |
---|
946 | </entry> |
---|
947 | </row> |
---|
948 | <row> |
---|
949 | <entry> |
---|
950 | <literal>pCurrentLogical</literal> |
---|
951 | </entry> |
---|
952 | <entry> |
---|
953 | The associated Logical Volume |
---|
954 | </entry> |
---|
955 | </row> |
---|
956 | <row> |
---|
957 | <entry> |
---|
958 | <literal>pMotherLogical</literal> |
---|
959 | </entry> |
---|
960 | <entry> |
---|
961 | The associated mother Logical Volume |
---|
962 | </entry> |
---|
963 | </row> |
---|
964 | <row> |
---|
965 | <entry> |
---|
966 | <literal>pAxis</literal> |
---|
967 | </entry> |
---|
968 | <entry> |
---|
969 | The axis along which the division is applied |
---|
970 | </entry> |
---|
971 | </row> |
---|
972 | <row> |
---|
973 | <entry> |
---|
974 | <literal>nDivisions</literal> |
---|
975 | </entry> |
---|
976 | <entry> |
---|
977 | The number of divisions |
---|
978 | </entry> |
---|
979 | </row> |
---|
980 | <row> |
---|
981 | <entry> |
---|
982 | <literal>width</literal> |
---|
983 | </entry> |
---|
984 | <entry> |
---|
985 | The width of a single division along the axis |
---|
986 | </entry> |
---|
987 | </row> |
---|
988 | <row> |
---|
989 | <entry> |
---|
990 | <literal>offset</literal> |
---|
991 | </entry> |
---|
992 | <entry> |
---|
993 | Possible offset associated to the mother along the axis of division |
---|
994 | </entry> |
---|
995 | </row> |
---|
996 | </tbody> |
---|
997 | </tgroup> |
---|
998 | </informaltable> |
---|
999 | </para> |
---|
1000 | |
---|
1001 | <para> |
---|
1002 | The parameterisation is calculated automatically using the |
---|
1003 | values provided in input. Therefore the dimensions of the solid |
---|
1004 | associated with <literal>pCurrentLogical</literal> will not be used, but |
---|
1005 | recomputed through the |
---|
1006 | <literal>G4VParameterisation::ComputeDimension()</literal> method. |
---|
1007 | </para> |
---|
1008 | |
---|
1009 | <para> |
---|
1010 | Since <literal>G4VPVParameterisation</literal> may have different |
---|
1011 | <literal>ComputeDimension()</literal> methods for each solid type, the user |
---|
1012 | must provide a solid that is of the same type as of the one |
---|
1013 | associated to the mother volume. |
---|
1014 | </para> |
---|
1015 | |
---|
1016 | <para> |
---|
1017 | As for any replica, the coordinate system of the divisions is |
---|
1018 | related to the centre of each division for the cartesian axis. For |
---|
1019 | the radial axis, the coordinate system is the same of the mother |
---|
1020 | volume. For the phi axis, the new coordinate system is rotated such |
---|
1021 | that the X axis bisects the angle made by each wedge, and Z remains |
---|
1022 | parallel to the mother's Z axis. |
---|
1023 | </para> |
---|
1024 | |
---|
1025 | <para> |
---|
1026 | As divisions are parameterised volumes with constant dimensions, |
---|
1027 | they may be placed inside other divisions, except in the case of |
---|
1028 | divisions along the radial axis. |
---|
1029 | </para> |
---|
1030 | |
---|
1031 | <para> |
---|
1032 | It is also possible to place other volumes inside a volume where a |
---|
1033 | division is placed. |
---|
1034 | </para> |
---|
1035 | |
---|
1036 | <para> |
---|
1037 | The list of volumes that currently support divisioning and the |
---|
1038 | possible division axis are summarised below: |
---|
1039 | |
---|
1040 | <informaltable> |
---|
1041 | <tgroup cols="2"> |
---|
1042 | <tbody> |
---|
1043 | <row> |
---|
1044 | <entry> |
---|
1045 | <literal>G4Box</literal> |
---|
1046 | </entry> |
---|
1047 | <entry> |
---|
1048 | <literal>kXAxis</literal>, <literal>kYAxis</literal>, <literal>kZAxis</literal> |
---|
1049 | </entry> |
---|
1050 | </row> |
---|
1051 | <row> |
---|
1052 | <entry> |
---|
1053 | <literal>G4Tubs</literal> |
---|
1054 | </entry> |
---|
1055 | <entry> |
---|
1056 | <literal>kRho</literal>, <literal>kPhi</literal>, <literal>kZAxis</literal> |
---|
1057 | </entry> |
---|
1058 | </row> |
---|
1059 | <row> |
---|
1060 | <entry> |
---|
1061 | <literal>G4Cons</literal> |
---|
1062 | </entry> |
---|
1063 | <entry> |
---|
1064 | <literal>kRho</literal>, <literal>kPhi</literal>, <literal>kZAxis</literal> |
---|
1065 | </entry> |
---|
1066 | </row> |
---|
1067 | <row> |
---|
1068 | <entry> |
---|
1069 | <literal>G4Trd</literal> |
---|
1070 | </entry> |
---|
1071 | <entry> |
---|
1072 | <literal>kXAxis</literal>, <literal>kYAxis</literal>, <literal>kZAxis</literal> |
---|
1073 | </entry> |
---|
1074 | </row> |
---|
1075 | <row> |
---|
1076 | <entry> |
---|
1077 | <literal>G4Para</literal> |
---|
1078 | </entry> |
---|
1079 | <entry> |
---|
1080 | <literal>kXAxis</literal>, <literal>kYAxis</literal>, <literal>kZAxis</literal> |
---|
1081 | </entry> |
---|
1082 | </row> |
---|
1083 | <row> |
---|
1084 | <entry> |
---|
1085 | <literal>G4Polycone</literal> |
---|
1086 | </entry> |
---|
1087 | <entry> |
---|
1088 | <literal>kRho</literal>, <literal>kPhi</literal>, <literal>kZAxis</literal> |
---|
1089 | </entry> |
---|
1090 | </row> |
---|
1091 | <row> |
---|
1092 | <entry> |
---|
1093 | <literal>G4Polyhedra</literal> |
---|
1094 | </entry> |
---|
1095 | <entry> |
---|
1096 | <literal>kRho</literal>, <literal>kPhi</literal>, <literal>kZAxis</literal> (*) |
---|
1097 | </entry> |
---|
1098 | </row> |
---|
1099 | </tbody> |
---|
1100 | </tgroup> |
---|
1101 | </informaltable> |
---|
1102 | </para> |
---|
1103 | |
---|
1104 | |
---|
1105 | <para> |
---|
1106 | (*) - <literal>G4Polyhedra</literal>: |
---|
1107 | |
---|
1108 | <itemizedlist spacing="compact"> |
---|
1109 | <listitem><para> |
---|
1110 | <literal>kPhi</literal> - the number of divisions has to be the same as |
---|
1111 | solid sides, (i.e. <literal>numSides</literal>), the width will |
---|
1112 | <emphasis>not</emphasis> be taken into account. |
---|
1113 | </para></listitem> |
---|
1114 | </itemizedlist> |
---|
1115 | </para> |
---|
1116 | |
---|
1117 | <para> |
---|
1118 | In the case of division along <literal>kRho</literal> of <literal>G4Cons</literal>, |
---|
1119 | <literal>G4Polycone</literal>, <literal>G4Polyhedra</literal>, if width is provided, it |
---|
1120 | is taken as the width at the <literal>-Z</literal> radius; the width at other |
---|
1121 | radii will be scaled to this one. |
---|
1122 | </para> |
---|
1123 | |
---|
1124 | <para> |
---|
1125 | Examples are given below in listings |
---|
1126 | <xref linkend="programlist_Geom.PhysVol_3" /> and |
---|
1127 | <xref linkend="programlist_Geom.PhysVol_4" />. |
---|
1128 | |
---|
1129 | <example id="programlist_Geom.PhysVol_4"> |
---|
1130 | <title> |
---|
1131 | An example of a box division along different axes, with or without offset. |
---|
1132 | </title> |
---|
1133 | <programlisting> |
---|
1134 | G4Box* motherSolid = new G4Box("motherSolid", 0.5*m, 0.5*m, 0.5*m); |
---|
1135 | G4LogicalVolume* motherLog = new G4LogicalVolume(motherSolid, material, "mother",0,0,0); |
---|
1136 | G4Para* divSolid = new G4Para("divSolid", 0.512*m, 1.21*m, 1.43*m); |
---|
1137 | G4LogicalVolume* childLog = new G4LogicalVolume(divSolid, material, "child",0,0,0); |
---|
1138 | |
---|
1139 | G4PVDivision divBox1("division along X giving nDiv", |
---|
1140 | childLog, motherLog, kXAxis, 5, 0.); |
---|
1141 | |
---|
1142 | G4PVDivision divBox2("division along X giving width and offset", |
---|
1143 | childLog, motherLog, kXAxis, 0.1*m, 0.45*m); |
---|
1144 | |
---|
1145 | G4PVDivision divBox3("division along X giving nDiv, width and offset", |
---|
1146 | childLog, motherLog, kXAxis, 3, 0.1*m, 0.5*m); |
---|
1147 | </programlisting> |
---|
1148 | </example> |
---|
1149 | |
---|
1150 | <itemizedlist spacing="compact"> |
---|
1151 | <listitem><para> |
---|
1152 | <literal>divBox1</literal> is a division of a box along its <literal>X</literal> |
---|
1153 | axis in 5 equal copies. Each copy will have a dimension in meters |
---|
1154 | of <literal>[0.2, 1., 1.]</literal>. |
---|
1155 | </para></listitem> |
---|
1156 | <listitem><para> |
---|
1157 | <literal>divBox2</literal> is a division of the same box along its |
---|
1158 | <literal>X</literal> axis with a width of <literal>0.1</literal> meters and |
---|
1159 | an offset of <literal>0.5</literal> meters. As the mother dimension along |
---|
1160 | <literal>X</literal> of |
---|
1161 | <literal>1</literal> meter (<literal>0.5*m</literal> of halflength), |
---|
1162 | the division will |
---|
1163 | be sized in total <literal>1 - 0.45 = 0.55</literal> meters. Therefore, |
---|
1164 | there's space for 5 copies, the first extending from <literal>-0.05</literal> |
---|
1165 | to <literal>0.05</literal> meters in the mother's frame and the last from |
---|
1166 | <literal>0.35</literal> to <literal>0.45</literal> meters. |
---|
1167 | </para></listitem> |
---|
1168 | <listitem><para> |
---|
1169 | <literal>divBox3</literal> is a division of the same box along its |
---|
1170 | <literal>X</literal> axis in 3 equal copies of width <literal>0.1</literal> |
---|
1171 | meters and an offset of <literal>0.5</literal> meters. |
---|
1172 | The first copy will extend from |
---|
1173 | <literal>0.</literal> to <literal>0.1</literal> meters in the mother's frame |
---|
1174 | and the last from <literal>0.2</literal> to <literal>0.3</literal> |
---|
1175 | meters. |
---|
1176 | </para></listitem> |
---|
1177 | </itemizedlist> |
---|
1178 | </para> |
---|
1179 | |
---|
1180 | <example id="programlist_Geom.PhysVol_5"> |
---|
1181 | <title> |
---|
1182 | An example of division of a polycone. |
---|
1183 | </title> |
---|
1184 | <programlisting> |
---|
1185 | G4double* zPlanem = new G4double[3]; |
---|
1186 | zPlanem[0]= -1.*m; |
---|
1187 | zPlanem[1]= -0.25*m; |
---|
1188 | zPlanem[2]= 1.*m; |
---|
1189 | G4double* rInnerm = new G4double[3]; |
---|
1190 | rInnerm[0]=0.; |
---|
1191 | rInnerm[1]=0.1*m; |
---|
1192 | rInnerm[2]=0.5*m; |
---|
1193 | G4double* rOuterm = new G4double[3]; |
---|
1194 | rOuterm[0]=0.2*m; |
---|
1195 | rOuterm[1]=0.4*m; |
---|
1196 | rOuterm[2]=1.*m; |
---|
1197 | G4Polycone* motherSolid = new G4Polycone("motherSolid", 20.*deg, 180.*deg, |
---|
1198 | 3, zPlanem, rInnerm, rOuterm); |
---|
1199 | G4LogicalVolume* motherLog = new G4LogicalVolume(motherSolid, material, "mother",0,0,0); |
---|
1200 | |
---|
1201 | G4double* zPlaned = new G4double[3]; |
---|
1202 | zPlaned[0]= -3.*m; |
---|
1203 | zPlaned[1]= -0.*m; |
---|
1204 | zPlaned[2]= 1.*m; |
---|
1205 | G4double* rInnerd = new G4double[3]; |
---|
1206 | rInnerd[0]=0.2; |
---|
1207 | rInnerd[1]=0.4*m; |
---|
1208 | rInnerd[2]=0.5*m; |
---|
1209 | G4double* rOuterd = new G4double[3]; |
---|
1210 | rOuterd[0]=0.5*m; |
---|
1211 | rOuterd[1]=0.8*m; |
---|
1212 | rOuterd[2]=2.*m; |
---|
1213 | G4Polycone* divSolid = new G4Polycone("divSolid", 0.*deg, 10.*deg, |
---|
1214 | 3, zPlaned, rInnerd, rOuterd); |
---|
1215 | G4LogicalVolume* childLog = new G4LogicalVolume(divSolid, material, "child",0,0,0); |
---|
1216 | |
---|
1217 | G4PVDivision divPconePhiW("division along phi giving width and offset", |
---|
1218 | childLog, motherLog, kPhi, 30.*deg, 60.*deg); |
---|
1219 | |
---|
1220 | G4PVDivision divPconeZN("division along Z giving nDiv and offset", |
---|
1221 | childLog, motherLog, kZAxis, 2, 0.1*m); |
---|
1222 | </programlisting> |
---|
1223 | </example> |
---|
1224 | |
---|
1225 | <itemizedlist spacing="compact"> |
---|
1226 | <listitem><para> |
---|
1227 | <literal>divPconePhiW</literal> is a division of a polycone along its |
---|
1228 | <literal>phi</literal> axis in equal copies of width 30 degrees with an |
---|
1229 | offset of 60 degrees. As the mother extends from 0 to 180 degrees, |
---|
1230 | there's space for 4 copies. All the copies have a starting angle of |
---|
1231 | 20 degrees (as for the mother) and a <literal>phi</literal> extension of 30 |
---|
1232 | degrees. They are rotated around the <literal>Z</literal> axis by 60 and 30 |
---|
1233 | degrees, so that the first copy will extend from 80 to 110 and the |
---|
1234 | last from 170 to 200 degrees. |
---|
1235 | </para></listitem> |
---|
1236 | <listitem><para> |
---|
1237 | <literal>divPconeZN</literal> is a division of the same polycone along |
---|
1238 | its <literal>Z</literal> axis. As the mother polycone has two sections, it |
---|
1239 | will be divided in two one-section polycones, the first one |
---|
1240 | extending from -1 to -0.25 meters, the second from -0.25 to 1 |
---|
1241 | meters. Although specified, the offset will not be used. |
---|
1242 | </para></listitem> |
---|
1243 | </itemizedlist> |
---|
1244 | </para> |
---|
1245 | |
---|
1246 | |
---|
1247 | </sect3> |
---|
1248 | </sect2> |
---|