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), Said Ahmad (3),  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). By default the entrance surface is set to the coordinates (0,0,0) as respect to the center of the world.
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 An array of Silicon Carbide (SiC) detectors is also implemented as geometry (default number of detectors=40, default center to center distance=3 mm, default single SiC detector size: 2x2 mm2 area, 10 um thickness for the active volume, 370 um thickness for the substrate layer) inside the water phantom and it is placed at 13 mm from the surface of the water phantom (depth of the maximum dose for 9 MeV electron beams).
0057 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 beginning of the class.
0058 The user can change the number of detectors and center to center distance by modifying the parameters (nDet and fDet_ctc respectively) at the beginning of the class. nDet can be set to 1 to have a single SiC detector.
0059 The SiC array is not activated by default and can be activated through the following macro command:
0060
0061 /changeDetector/activateArray true
0062
0063 This macro command must be applied before initialization (/run/initialize).
0064
0065 The user may also change the material of the detector trough macro commands:
0066
0067 /changeDetector/material G4_C
0068 /chageDetector/update
0069
0070
0071 =====================PRIMARY GENERATOR=====================
0072
0073 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).
0074 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")
0075 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
0076 FlashPrimaryGeneratorAction.cc.
0077
0078
0079 =====================SCORING MESH=====================
0080
0081 Two scoring meshes are implemented as default in .mac file commands.
0082 The first one (boxMesh_1) is a 120x4x4 mm3 scorer with 120x1x1 number nbin while second scorer (boxMesh_1) is a 4x4x150 mm3 scorer with 1x1x150 number of beam, simulating a similar volume as the Advanced Markus Chamber 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_longitudinal.out and dose_transversal.out at the end of the simulation and represent the depth dose and transversal dose distributions respectively of the electron beams (9 MeV as default) as reported in Di Martino et al., Front. Phys. 11:1268310.
0083 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).
0084
0085
0086 =====================SENSITIVE DETECTOR=====================
0087 The FlashSensitiveDetector class is also imlemented for the Silicon carbide detector array. It is only activated if the array is activated through the following command: /changeDetector/activateArray true.
0088 The output file is .csv file by default. The user may change the output file format (e.g. .root) by modifying the argument of fAnalysisManager->OpenFile inside FlashRunAction::BeginOfRunAction.
0089
0090 An output csv file (output_0_nt_fSensitiveDetector_t*.csv)  will be produced for each thread (in case of multhidreading=ON) and contains the following information for each Silicon carbide detector composing the array and for each step within the sensitive volume:
0091
0092 detector position x, detector position y, detector position z, dose deposited, energy deposited, eventID, parentID, particle name
0093
0094
0095
0096 =====================ENERGY SPECTRUM AT THE WATER PHANTOM ENTRANCE=====================
0097 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:
0098
0099 parentid eventid kineticEnergy pos_x pos_y pos_z momentum  cos_x cos_y cos_z
0100
0101 If user is not interested on the retrieval of the energy spectrum can easily comment the line in the SteppingAction class.
0102
0103
0104 =====================PHYSICS PROCESSES AND PHYSICS LIST =====================
0105
0106 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
0107 in the FlashDetectorConstruction Class (Default region is the water phantom).
0108
0109
0110