Gabriele Cosmo
62 lines
4.1 KiB
Plaintext
62 lines
4.1 KiB
Plaintext
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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icsd
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Authors: Sylvain Meylan et Carmen Villagrasa (IRSN, France)
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For any question, please contact:
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carmen.villagrasa@irsn.fr
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This example is provided by the Geant4-DNA collaboration
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Any report or published results obtained using the Geant4-DNA software
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shall cite the following Geant4-DNA collaboration publications:
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[1] Med. Phys. 37 (2010) 4692-4708
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[2] Phys. Med. 31 (2015) 861-874
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In addition, for this example using DNA-materials cross-sections, please cite:
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[3] Rad. Phys and Chem. 130 (2017) 459-479
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---->0. INTRODUCTION.
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The icsd name of this example stands for: Ionisation Cluster Size Distribution.
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This example allows the calculation of the distribution concerning the number of ionisations per event in an small cylinder of 2.3 nanometers diameter and 3.4 nanometers heigh, typical dimensions of a 10 base pairs piece of chromatin.
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It constitutes the first use of new DNA-like material's cross-sections that were experimentally obtained at PTB (Rad. Phys and Chem. 130 (2017) 459-479) for electrons and calculated for protons on THF, TMP, PY and PU materials.
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The new physical models corresponding to the DNA materials have recently been implemented in Geant4-DNA thaks to new classes, that allow the use of other materials different from liquid water: G4VDNAModel, G4DNAModelInterface,G4DNADummyModel and other associated classes.
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These new models are further described at:
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http://geant4-dna.org
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---->1. GEOMETRY SET-UP AND PRIMARY PARTICLES
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As indicated in the introduction, the geometry used in this exercise is very simple: a cylinder of 2.3 nanometers diameter and 3.4 nanometers heigh, typical dimensions of a 10 base pairs piece of chromatin that is centered in a cubic world of 10 nanometers side length filled with liquid water.
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This cylinder is filled with THF material. The definition of the THF material must be done using the G4String="THF". Currently, other materials are available than also use the G4Strings to be recognized by the model classes "TMP", "PY" or "PU" for the DNA-like materials and "deoxyribose","adenine", "guanine", "thymine" or "cytosine" for the derived DNA materials.
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Primary particles are electrons starting at (-1.15 nanometers, 0,0) (at the cylinder's edge) and initial momentum (1,0,0)
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---->2. PHYSICS LIST
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The PhysicsList used in this example show how to use the new classes that allow Geant4-DNA to use other materials than liquid water :
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1/ Models are built: classical Geant4-DNA models for liquid water material and PTB models for DNA-like materials
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2/ G4DNAModelInterface object is built for each type of interaction (elastic, ionisation, excitation)
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3/ G4DNAModels are registered within the corresponding G4DNAModelInterface. For liquid water models, the particle name must be added to the RegisterModel function. For DNA-like material models and Vacuum no other parameter is needed.
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4/ G4DNAProcesses objects are built and the corresponding G4DNAModelInterface is registered within. G4DNAModelInterface acts like a classical G4VEmModel
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Remember that new DNA-like material classes are available for:
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electrons from 12 eV-1 keV, including elastic, ionisation and excitation processes
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protons from 70 keV to 10 MeV, only for ionisation processes following a modified HKS formalism
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---->3. SET UP
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Make sure G4LEDATA points to the low energy electromagnetic data files.
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---->4. HOW TO RUN THE EXAMPLE
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./icsd will run in multi-threaded mode with 2 threads by default.
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Two ntuples will be filled in the output file:
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- Ntuple 1 contains the information for calculating the ionisation cluster size distribution per event
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- Ntuple 2 contains interaction information at the step level
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