advanced/eFLASH_radiotherapy/README.txt

0001
0002              =========================================================
0003                      Text version of the eFLASH_radiotherapy README file
0004              =========================================================
0005
0006 Authors:
0007 Jake Harold Pensavalle (1,2), Giuliana Milluzzo (3) and Francesco Romano (3)
0008
0009
0010  (1) Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, ed.18 via Roma 67 Pisa, Italy
0011
0012  (2) Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Largo B. Pontecorvo 3 I Pisa, Italy
0013
0014  (3) Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Via Santa Sofia 64 Catania, Italy
0015
0016
0017 ---Contacts:
0018
0019 Jake Pensavalle: jake.pensavalle@pi.infn.it
0020
0021 Giuliana Milluzzo: giuliana.milluzzo@ct.infn.it
0022
0023 Francesco Romano: francesco.romano@ct.infn.it
0024
0025
0026 WHAT IT IS, WHAT IT DOES AND WHAT IT WILL PROVIDE
0027
0028 This Example "FLASH" simulates the beamline and energy spectra based on the Triode Electron Gun Equipped ElectronFlash Manufactured by Sordina Iort Technologies S.p.A. available at the Centro Pisano Flash Radiotherapy (CPFR) at Pisa.  The linac is able to provide low-energy electron flash beams and is currently the first machine installed in Italy capable of reaching  FLASH dose-rate (MGy/s) and extremely high dose per pulse DPP).
0029
0030
0031 =====================BEAMLINE===============================
0032 The beamline (set along the x-axis) is modelled in the Applicator class, starting from the titanium windows (which is after the RF cavities not modelled in this simulation) ending at the PMMA applicator which acts as a passive collimation of the electron beam.
0033 The applicator has 5mm thick walls and the user can set the inner and outer radius and the total length of the applicatior in the Applicator.cc class by modifying the appropriate parameters (OuterRadiusFirstApplicatorFlash and hightFinalApplicatorFlash)  by means of the SetApplicatorLength and SetOuterRadius functions. The default is the 100mm diameter applicator (inner diameter), but one can
0034 simulate the others as follows:
0035
0036 1) Applicator (internal diameter) 30mm : OuterRadiusFirstApplicatorFlash = 17.5 mm,  hightFinalApplicatorFlash = 175 mm
0037
0038 2) Applicator (internal diameter) 40mm : OuterRadiusFirstApplicatorFlash = 22.5 mm,  hightFinalApplicatorFlash = 200 mm
0039
0040 2) Applicator (internal diameter) 50mm : OuterRadiusFirstApplicatorFlash = 27.5 mm,  hightFinalApplicatorFlash = 225 mm
0041
0042 Optionally one can set the length of the applicator to 0 and simulate the beam at  the exit window, an additional 3cm of air are between the phantom to account for the applicator inserter hooks on the machine.
0043
0044 =====================DETECTOR CONSTRUCTOR===============================
0045
0046 The FlashDetectorConstruction Class creates a cubic water phantom (default dimension 30x30x30 cm3) and a detector volume.
0047 The phantom is placed in contact with the applicator as a typical experimental setup as default. The Phantom sizes can be easily modified by using the SetPhantomSize function at the beginning of the class.
0048 The user can also add an air gap between the end of the final applicator and the entrance of the water phantom by modifying the parameter (AirGap) and the function SetAirGap (default AirGap=0 cm).
0049 The defaul material of the phantom is water (G4_WATER) but the material can be easily changed by using the following macro commands:
0050 Es:
0051 /changePhantom/material G4_AIR
0052 /chagePhantom/update
0053
0054 The user may also select the maximum step length in this class by changing the "maxStep" parameter.
0055
0056 A silicon carbide (SiC) detector (default thickness=10 um, default substrate=370 um, default width=5 mm) is also implemented outside the water phantom and attacched to the exit surface of the water phantom. The width and the thickness of the active layer and of the substrate can be easily modified by means of the SetDetectorThickness, SetDetector_subThickness, SetDetectorWidth functions at the beginnign of the class.
0057 An air gap between the phantom exit and the entrance of the detector can be also added through the SetAirGap_water_detector function.
0058 The user may also change the material of the detector trough macro commands:
0059
0060 /changeDetector/material G4_C
0061 /chageDetector/update
0062
0063
0064 =====================PRIMARY GENERATOR=====================
0065
0066 The source is modelled in the FlashPrimaryGeneratorAction class and fully uses the General Particle Source class (both in .mac commands and directly in c++ code).
0067 The beam spot is gaussian with a slight angular divergence (1.5 deg) and the electron energy spectrum can be loaded from macro commands  chosing the 9MeV mode (using "/control/execute 9MeVEF.mac")
0068 or the 7MeV mode (using "/control/execute 7MeVEF.mac). The geometry of the beam can be set by the user by changing the position, sigma and theta values in
0069 FlashPrimaryGeneratorAction.cc.
0070
0071
0072
0073 =====================SCORING MESH=====================
0074
0075 A scoring mesh is implemented in .mac file commands.
0076 A default 120x4x4 mm3 scorer with 120x1x1 number nbin simulating a similar volume as the Advanced Markus Chamber is created in the position of the water phantom to register the dose in Gy delivered in each voxel. Results are printed in the file dose.out at the end of the simulation. User may change the dimensions and bin number (voxel size) to appropiately score the volume of interest and optimize the simulation (a very finely voxellized volume may increase the simulation time significantly).
0077
0078 =====================ENERGY SPECTRUM=====================
0079 The primary particle energy spectrum at the entrance of the phantom (downstream the beamline) is also registered using the FlashSteppingAction class. An ASCII file is automatically written with the following information:
0080
0081 parentid eventid kineticEnergy pos_x pos_y pos_z momentum  cos_x cos_y cos_z
0082
0083 If user is not interested on the retrieval of the energy spectrum can easily comment the line in the SteppinAction class.
0084
0085
0086 =====================PHYSICS PROCESSES AND PHYSICS LIST =====================
0087
0088 EM Standard option 4 is activated. The user can change the physics list in the physics list class. A production cut for gammas e+ and e- can be applied provided the specification of the Region name defined
0089 in the FlashDetectorConstruction Class (Default region is the water phantom).
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0092