[904] | 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.Reflec"> |
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| 12 | <title> |
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| 13 | Reflecting Hierarchies of Volumes |
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| 14 | </title> |
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| 15 | |
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| 16 | <para> |
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| 17 | Hierarchies of volumes based on <emphasis>CSG</emphasis> or |
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| 18 | <emphasis>specific</emphasis> solids can be reflected by means of the |
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| 19 | <literal>G4ReflectionFactory</literal> class and <literal>G4ReflectedSolid</literal>, |
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| 20 | which implements a solid that has been shifted from its original |
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| 21 | reference frame to a new 'reflected' one. The reflection |
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| 22 | transformation is applied as a decomposition into rotation and |
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| 23 | translation transformations. |
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| 24 | </para> |
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| 25 | |
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| 26 | <para> |
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| 27 | The factory is a singleton object which provides the following |
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| 28 | methods: |
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| 29 | |
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| 30 | <informalexample> |
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| 31 | <programlisting> |
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| 32 | G4PhysicalVolumesPair Place(const G4Transform3D& transform3D, |
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| 33 | const G4String& name, |
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| 34 | G4LogicalVolume* LV, |
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| 35 | G4LogicalVolume* motherLV, |
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| 36 | G4bool isMany, |
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| 37 | G4int copyNo, |
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| 38 | G4bool surfCheck=false) |
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| 39 | |
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| 40 | G4PhysicalVolumesPair Replicate(const G4String& name, |
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| 41 | G4LogicalVolume* LV, |
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| 42 | G4LogicalVolume* motherLV, |
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| 43 | EAxis axis, |
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| 44 | G4int nofReplicas, |
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| 45 | G4double width, |
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| 46 | G4double offset=0) |
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| 47 | |
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| 48 | G4PhysicalVolumesPair Divide(const G4String& name, |
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| 49 | G4LogicalVolume* LV, |
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| 50 | G4LogicalVolume* motherLV, |
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| 51 | EAxis axis, |
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| 52 | G4int nofDivisions, |
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| 53 | G4double width, |
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| 54 | G4double offset); |
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| 55 | </programlisting> |
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| 56 | </informalexample> |
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| 57 | </para> |
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| 58 | |
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| 59 | <para> |
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| 60 | The method <literal>Place()</literal> used for placements, evaluates the |
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| 61 | passed transformation. In case the transformation contains a |
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| 62 | reflection, the factory will act as follows: |
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| 63 | |
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| 64 | <orderedlist spacing="compact"> |
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| 65 | <listitem><para> |
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| 66 | Performs the transformation decomposition. |
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| 67 | </para></listitem> |
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| 68 | <listitem><para> |
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| 69 | Creates a new reflected solid and logical volume, or retrieves |
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| 70 | them from a map if the reflected object was already created. |
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| 71 | </para></listitem> |
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| 72 | <listitem><para> |
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| 73 | Transforms the daughters (if any) and place them in the given mother. |
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| 74 | </para></listitem> |
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| 75 | </orderedlist> |
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| 76 | </para> |
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| 77 | |
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| 78 | <para> |
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| 79 | If successful, the result is a pair of physical volumes, where the |
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| 80 | second physical volume is a placement in a reflected mother. |
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| 81 | Optionally, it is also possible to force the overlaps check at the |
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| 82 | time of placement, by activating the <literal>surfCheck</literal> flag. |
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| 83 | </para> |
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| 84 | |
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| 85 | <para> |
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| 86 | The method <literal>Replicate()</literal> creates replicas in the given |
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| 87 | mother. If successful, the result is a pair of physical volumes, |
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| 88 | where the second physical volume is a replica in a reflected |
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| 89 | mother. |
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| 90 | </para> |
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| 91 | |
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| 92 | <para> |
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| 93 | The method <literal>Divide()</literal> creates divisions in the given mother. |
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| 94 | If successful, the result is a pair of physical volumes, where the |
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| 95 | second physical volume is a division in a reflected mother. There |
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| 96 | exists also two more variants of this method which may specify or |
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| 97 | not width or number of divisions. |
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| 98 | </para> |
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| 99 | |
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| 100 | <note> |
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| 101 | <title> |
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| 102 | Notes |
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| 103 | </title> |
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| 104 | <para> |
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| 105 | <itemizedlist spacing="compact"> |
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| 106 | <listitem><para> |
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| 107 | In order to reflect hierarchies containing divided volumes, it |
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| 108 | is necessary to explicitely instantiate a concrete <emphasis>division</emphasis> |
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| 109 | factory -before- applying the actual reflection: (i.e. - |
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| 110 | <literal>G4PVDivisionFactory::GetInstance();</literal>). |
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| 111 | </para></listitem> |
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| 112 | <listitem><para> |
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| 113 | Reflection of generic parameterised volumes is not possible yet. |
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| 114 | </para></listitem> |
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| 115 | </itemizedlist> |
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| 116 | </para> |
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| 117 | </note> |
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| 118 | |
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| 119 | <example id="programlist_Geom.Reflec_1"> |
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| 120 | <title> |
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| 121 | An example of usage of the |
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| 122 | <literal>G4ReflectionFactory</literal> class.</title> |
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| 123 | <programlisting> |
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| 124 | #include "G4ReflectionFactory.hh" |
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| 125 | |
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| 126 | // Calor placement with rotation |
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| 127 | |
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| 128 | G4double calThickness = 100*cm; |
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| 129 | G4double Xpos = calThickness*1.5; |
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| 130 | G4RotationMatrix* rotD3 = new G4RotationMatrix(); |
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| 131 | rotD3->rotateY(10.*deg); |
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| 132 | |
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| 133 | G4VPhysicalVolume* physiCalor = |
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| 134 | new G4PVPlacement(rotD3, // rotation |
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| 135 | G4ThreeVector(Xpos,0.,0.), // at (Xpos,0,0) |
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| 136 | logicCalor, // its logical volume (defined elsewhere) |
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| 137 | "Calorimeter", // its name |
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| 138 | logicHall, // its mother volume (defined elsewhere) |
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| 139 | false, // no boolean operation |
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| 140 | 0); // copy number |
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| 141 | |
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| 142 | // Calor reflection with rotation |
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| 143 | // |
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| 144 | G4Translate3D translation(-Xpos, 0., 0.); |
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| 145 | G4Transform3D rotation = G4Rotate3D(*rotD3); |
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| 146 | G4ReflectX3D reflection; |
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| 147 | G4Transform3D transform = translation*rotation*reflection; |
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| 148 | |
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| 149 | G4ReflectionFactory::Instance() |
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| 150 | ->Place(transform, // the transformation with reflection |
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| 151 | "Calorimeter", // the actual name |
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| 152 | logicCalor, // the logical volume |
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| 153 | logicHall, // the mother volume |
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| 154 | false, // no boolean operation |
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| 155 | 1, // copy number |
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| 156 | false); // no overlap check triggered |
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| 157 | |
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| 158 | // Replicate layers |
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| 159 | // |
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| 160 | G4ReflectionFactory::Instance() |
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| 161 | ->Replicate("Layer", // layer name |
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| 162 | logicLayer, // layer logical volume (defined elsewhere) |
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| 163 | logicCalor, // its mother |
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| 164 | kXAxis, // axis of replication |
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| 165 | 5, // number of replica |
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| 166 | 20*cm); // width of replica |
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| 167 | </programlisting> |
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| 168 | </example> |
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| 169 | |
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| 170 | </sect2> |
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