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

1Map of Models used in PHITS2.82
NeutronProton, Pion(other hadrons)

NucleusLow ← Energy → High

1 TeVMuone- / e+Photon

1 TeV/n

1 TeV

EGS5 EGS5
VirtualQuantum
PhotoNuclear
Molecular Photoor
orJAM/
Dynamics Nuclear
QMD
JAM/
Intra-nuclear cascade (INCL4.6) d (JQMD)
AtomicAtomic+JQMD++Data
GEM
Data+t+Evaporation (GEM)
Evaporation GEM Library Library
3He(EEDL / JENDL-4.0 JENDL(GEM)
20 MeV
200 MeV
Intra-nuclear cascade (JAM)+ Evaporation
3.0 GeV (GEM)

NuclearData Library(JENDL-4.0)
10-5 eV

α1 MeV
1 keV

10 MeV/nIonization
SPAR or ATIMA+ITS3.0 / / EPDL97
EPDL97) (~100GeV) NRF(~10GeV)
2 MeV

1 keV

1 keV

Event generator mode: all secondary particles are specified

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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 source3Tetrahedral Geometry What’s tetrahedral geometry?
A kind of 3D polygon geometrycomposed only by tetrahedrons
 What’s the purpose of implementation?
Read complicated geometry such as
human body
Read CAD geometry via tetrahedralgeometry
 How to use? (see utility/TetraGeom)
Similar to voxel geometry
You have to prepare tetrahedral geometry
using other software such as TetGen** http://wias-berlin.de/software/tetgen/

Voxel phantom Polygon phantom(ICRP [1])(Hanyang Univ. [2])[1] ICRP Publication 110, [2] Y.S. Yeom et al. Phys. Med. Biol. 59, 3173-3185 (2014)This implementation was performed under support of Prof. C.H. Kim’s group of Hanyang Univ4Muon Transport Algorithm
 Virtual photon interaction (ver.2.70)
 Negative muon capture reaction (ver.2.76)

Bremsstrahlung
CharacteristicMuon
P.P. X-ray

 Bremsstrahlung, pair production (ver.2.80) Virtual photon

0-3-5

1045deg.

-610-710-81090deg.
(x 0.1)135deg.
-9 (x 0.01)
101
23101010
Neutron energy (MeV)

12C(μ,n) @ 190GeV/c-1

10Sundelin, 1973
PHITS

2Chazal, 2002
PHITS

10-2

10-310-410-5

100

Vertical intensity (/cm /sr/s)-410Capture-5

1010Count (/cap/MeV)

Double differential cross section(barn/sr/10MeV)

All interaction can be considered!!

NuclearReaction

10 20 30 40 50 60
Neutron energy (MeV)

40Ca(μ-,n) @ captured

w/o interaction
with interaction
Crouch,1987
Aglietta,1998

-6

10-7

10

normalized
-8

10-9

100.5

1.0 1.5 2.0 2.5 3.0
Underground depth (km)Under ground Muon
5

Nuclear Resonance Florescence (NRF)
What’s NRF?
Photo-nuclear X.sec

Nucleus can absorb photon with energy equivalent to its excite level, andemit gamma-ray with certain energies (a kind of photo-nuclear reaction)
・Giant Resonance
・QDD etc

NRFNewOld~8Application
 Estimation of radioactivity after
food irradiation
 Detection of nuclear material

Energy (MeV)

How to use

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 (http://www.nndc.bnl.gov/nudat2/)
6

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

Reduce computational time in air
Calculation of depth-dose distribution for 200
MeV in 10 m air
idelt=0:
Old methd
idelt=1:
New method

idelt=1(new option): Determine maximum
flight path / event based on g/cm2
Reduce computational time by factor 1.6
7

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