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--- software:g4simulation:radiation_studies [2020/07/07 07:13] – [First example] himuser
+++ software:g4simulation:radiation_studies [2022/03/14 13:53] (current) – himuser
@@ Line 58: / Line 58: @@
       * instantiates a sensitive detector and assigns it to the full hall
     * ''class PRIMARadStudiesSD''\\ sensitive detector (derives from ''G4VSensitiveDetector'') holding the radiation map (''PRIMARadStudiesMap'' object).
-      * The ''ProcessHit'' functioning is:
+      * The ''ProcessHit'' functioning:
         * finds the voxel corresponding to the mid point of the step
         * calculates the energy deposit to density ratio
         * creates/updates map entry for that voxels
       * A method ''WriteTextFile'' is provided to dump the map into a ASCII file for testing purposes. Activation and output file name are hard coded so far. Dynamical settings could be added to ''PRIMASimulationConfig'' if needed.
-  * ''rootmacros/rad_studies.C''\\ example macro for reading and handling the radiation map. The example loops over the map entries and makes a 2d map for the region around the yz-plane (vertical plane containing the beam direction).
 ==== First example ====
+In the example a geometry containing only the target, the vacuum volume and parts of the beam pipe downstream of the scattering chamber is defined. The radiation dose is scored over the full hall subdivided in voxels of 1 cm side length.
 == Geometry ==
+  * Two new materials (TGeoMedium) have been defined:
+    * Tantalum for the target
+    * Iron for the octagonal pipe. The density of the pure iron "Armco-Eisen" has been used.
+  * Two support functions are defined and implemented in ''geometry/PRIMABeamPipe.{hh,cc}''
+    * ''TGeoVolume* ConstructVacuumVolume()''\\ defines the vacuum volume, i.e. inner scattering chamber and inner beam pipe, as a single ''TGeoVolume'' from a composite shape. This is important to ensure that the beam electrons inside the vacuum can travel until the end of the hall without unwanted material layers.
+    * ''TGeoVolumeAssembly* ConstructBeamPipe()''\\ places the vacuum volume, the aluminium flange at the target chamber exit, and a simplified "octagonal" pipe (defined as a cone) inside a ''TGeoVolumeAssembly''
-== Settings ==
+  * A new main is implemented in ''geometry/build_beam_pipe.cxx'' for generating the root file with the geometry, containing the assembly described above and the tantalum target inside the hall.
+== Geant4 Settings ==
+  * Geometry: as just described.
+  * Primary generator: the particle gun shooting electrons
+    * from the beam axis upstream of the target
+    * in the beam direction (positive z direction)
+    * with an energy of 1.5 GeV
+  * Simulated events: 10<sup>6</sup>
 == Results ==
+In order to analyse the output map from the geant4 simulation the example macro ''rootmacros/rad_studies.C'' has been introduced. It shows:
+  * how to read and handle the radiation map,
+  * how to loop over the map entries, and
+  * make a 2d map for the region around the yz-plane (vertical plane containing the beam direction).
+{{ :software:g4simulation:rad_map_x0_example.png?nolink&500 |}}
+== FLUKA simulations ==
+A guide to the FLUKA simulations using Flair can be found [[FLUKA#Simulations|here]]