Features of PHITS2.82. PHITS development team, Dec. 25, 2015

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Brooke Craig
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1 1 Features of PHITS2.82 PHITS development team, Dec. 25, 2015

2 Map of Models used in PHITS2.82 Low Energy High Neutron Proton, Pion (other hadrons) 1 TeV 1 TeV/n Intra-nuclear cascade (JAM) Evaporation 3.0 GeV (GEM) Intra-nuclear cascade (INCL4.6) Evaporation (GEM) 20 MeV Nuclear Data Library (JENDL-4.0) 10-5 ev 1 MeV 1 kev d t 3 He α Nucleus Muon e - / e Quantum Molecular Dynamics (JQMD) Evaporation (GEM) 10 MeV/n Ionization SPAR or ATIMA Virtual Photo- Nuclear JAM/ JQMD GEM 200 MeV EGS5 Event generator mode: all secondary particles are specified or Atomic Data Library (EEDL / ITS3.0 / EPDL97) (~10GeV) EGS5 or Photon Atomic Data Library JENDL-4.0 / EPDL97 (~100GeV) 1 kev 1 kev 1 TeV Photo- Nuclear JAM/ QMD GEM JENDL NRF 2 MeV Maximum energy is extended up to 1 TeV/n by fixing bugs in high-energy nuclear reaction models *Switching energies can be changed in input file of PHITS 2

3 3 Major Upgraded Features from v2.76 Implementation of function to read tetrahedral geometry Improvement of muon transport algorithm Implementation of nuclear resonance florescence model Extension of sum tally Implementation of function to read user defined cross section Revision of energy straggling calculation procedure Revision of statistical uncertainty calculation procedure using dump source Revision of bugs in EGS5 mode Implementation of point estimator tally [t-point] Implementation of R-θ-Z mesh in [t-track] Implementation of function to generate triangle prism source

Tetrahedral Geometry What s tetrahedral geometry?

Read complicated geometry such as human body Read CAD geometry via tetrahedral geometry How to use?

software such as TetGen* * http://wias-berlin.

4 Tetrahedral Geometry What s tetrahedral geometry? A kind of 3D polygon geometry composed only by tetrahedrons What s the purpose of implementation? Read complicated geometry such as human body Read CAD geometry via tetrahedral geometry How to use? (see utility/tetrageom) Similar to voxel geometry You have to prepare tetrahedral geometry using other software such as TetGen* * Voxel phantom (ICRP [1]) Polygon phantom (Hanyang Univ. [2]) [1] ICRP Publication 110, [2] Y.S. Yeom et al. Phys. Med. Biol. 59, (2014) This implementation was performed under support of Prof. C.H. Kim s group of Hanyang Univ 4

5 Muon Transport Algorithm Virtual photon interaction (ver.2.70) Negative muon capture reaction (ver.2.76) Bremsstrahlung, pair production (ver.2.80) All interaction can be considered!! Bremsstrahlung Characteristic Muon P.P. X-ray Virtual photon Nuclear Reaction Capture Double differential cross section (barn/sr/10mev) deg. (x 0.01) Chazal, 2002 PHITS 45deg. 90deg. (x 0.1) Neutron energy (MeV) Count (/cap/mev) GeV/c 40 Ca(μ captured Sundelin, 1973 PHITS Neutron energy (MeV) Vertical intensity (/cm 2 /sr/s) normalized w/o interaction with interaction Crouch,1987 Aglietta, Underground depth (km) Under ground Muon 5

6 Nuclear Resonance Florescence (NRF) What s NRF? Nucleus can absorb photon with energy equivalent to its excite level, and emit gamma-ray with certain energies (a kind of photo-nuclear reaction) Photo-nuclear X.sec New NRF ~ 8 Giant Resonance QDD etc Old Energy (MeV) How to use Application Estimation of radioactivity after food irradiation Detection of nuclear material 1. Set ipnint = 2 in [parameters] section 2. Set polarization direction in [source] section (for polarized photon) 3. Set igamma = 3 if you would like to calculate isomer production Absorption levels are mostly taken from ENSDF ( 6

idelt=1: New method Reduce computational time in air Calculation of depth-dose distribution for 200 MeV in 10 m

7 Revision of Energy Straggling Problem on calculating energy straggling in large material PHITS2.76 After PHITS2.80 Depth-dose distribution around 200 MeV proton Blue: 1mm x 280 cells Red: 28cm x 1 cell idelt=0: Old methd idelt=1: New method Reduce computational time in air Calculation of depth-dose distribution for 200 MeV in 10 m air idelt=1(new option): Determine maximum flight path / event based on g/cm 2 Reduce computational time by factor 1.6 7

Point Tally [t-point] What s point tally?

region is very small in comparison to whole geometry Simulation Condition

neutron and photon can be estimated Neither event-generator and EGS5 mode

8 Point Tally [t-point] What s point tally? Estimate particle fluence at a certain point (or line) Effective when tally region is very small in comparison to whole geometry Simulation Condition Simulation using only nuclear and atomic data libraries Only fluence of neutron and photon can be estimated Neither event-generator and EGS5 mode cannot be used [t-point] [t-track] Neutron and photon fluence calculated by [t-point] and [t-track] for similar conditions 8

Improvements and developments of physics models in PHITS for radiotherapy and space applications

Improvements and developments of physics models in PHITS for radiotherapy and space applications L. Sihver 1-9, T. Sato 10, S. Hashimoto 10, T. Ogawa 10, K. Niita 11 1 Atominstitut, TU Wien, Austria, 2