Features of PHITS3.34
PHITS development team, Apr. 2024

1

Number of PHITS users since 2019
Top 10 countries
Country#users

Japan

2873

Indonesia

410

United States

333

South Korea

249

Philippines

211

China

165

France148

Argentina

129

Number of PHITS users in each country since 2019*

Spain

114

*@03/04/2024, based on the location of users’ affiliation

Malaysia

113

5,890 new users from 76 countries in five years!
https://phits.jaea.go.jp/usermap/PHITS_map_userbase.html

2Map of Models Recommended to Use in PHITS
ProtonLow ← Energy → High

Neutron

NucleusMuon1 TeV

1 TeV/n

1 TeV

JAM + GEM

JAMQMD+ GEM

e- / e+Photon
1 TeV

JAM/
JQMD+GEM

JAM/
JQMD
t
EGS5,
JQMD
+EPDL97
3HeETSINCL4.6 + GEM+GEMororα
200 MeV
200 MeV
GEM+ETSART EGS5JENDLdJENDL-5
20 MeV
ATIMA
10 MeV/n++
1 MeV
NRF
Original ModelJENDL-4
ATIMA oror
1 keV KURBUC / ITSART
1 keV
1 keV
1 keV
JENDL-5 *Only for negative muon capture
ETS or*JQMD +ETSART
GEM
0.01 meV
1 meV
3.0 GeV

Red: Nuclear reaction model or library

Blue: Atomic interaction model or library

Models and libraries highlighted in gray are not used in the default setting

JENDL-5 is recommended to use for neutrons, protons, and deuterons if available

3

Major Upgraded Features in ver. 3.34
Since version 3.31
 A function for calculating extended statistical indicators has been implemented
 A new program for analyzing the chemical reactions (PHITS-Chem) has been developed An electron track-structure model applicable to arbitrary target (ETSART) has been developed [weight window] and [t-wwg] have been improved in various aspects
 [Forced collisions] has become applicable to thick targets for charged particle irradiation*1)
 An adjoint mode applicable to charged particles has been implemented
 An automatic download and setup program for JENDL-5 has been developed*2)
 A text editor specialized for making PHITS input file (PHITS-Pad) has been developed*3)
 A function to visualize 4-dimensional (x,y,z,t) particle trajectory has been implemented in PHIG-3D*4)*1) Under the support of RIST
*2) Under the support of AdvanceSoft Corporation*3) Under the support of CCCE of JAEA*4) Under the support of National Maritime Research Institute4

Major Upgraded Features in ver. 3.34
Since version 3.31
 JENDL-4.0/HE and JENDL/DEU-2020 were replaced by JENDL-5*1)
 A new function to output the multiplier values has been implemented*2)
 The installer for Windows has been updated*3)
 A new function to scale the maximum tally output value to a certain value has been implemented*4)
 A function to consider the detector resolutions has been implemented in [t-deposit2]
 A function to read neutron libraries for meta-stable nuclides has been implemented
 The algorithm of ITSART has been improved Weighting factors defined in [multiplier] as a function of LET can be considered in [t-deposit]
 [User-Defined Interaction] and [User Defined Particle] have been developed Categories of reaction channels for track-structure modes in [t-interact] have been re-organized*1) Under support of Dr. Konno, Dr. Tada, Dr. Nakayama, Dr. Iwamoto of JAEA
*2) Under support of RIST
*3) Under the support of AdvanceSoft Corporation*4) Under the support of CCCE of JAEA

5Extended statistical indicators
1.
2.

Output function of new statistical indicators for tally results: variance of the variance (VOV),
figure of merit (FOM), and probability density function.
Statistical check sheet to confirm convergence of statistical indicators.

Transition of VOV (left panel) and FOM (right panel)as the total history number increases.
••

VOV, variance of statistical error, decreases by 1/N.
FOM, computational efficiency over time, converges to a
constant value.

Statistical check sheet

See Sec. 6.10 of PHITS manual (sample input in phits/sample/itall3)

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Development of chemical code in PHITS Estimate of G values resulting from water radiolysis using track-structure mode Considering the generation, diffusion, and reaction of 13 types of chemical products※ Chemical species ： •OH, eaq–, •H, H3O+, H2, H2O2, HO2, O2,OH–, O2–, HO2–, •O•, O–[Track-structure mode (PHITS-ETS)]
Output of the atomic interaction
e.g.,10 keV esource[Developed code（PHITS-Chem code)]

Consideration ofgeneration, diffusion,and reaction of13 chemical products•OH radicalRegions where track structuremode is activatedscavenger of(Tris, DMSO)
can be considered!

Succeeded in developing a chemical code for PHITS that can reproduce
experimental values and other simulation codes!
See phits/utility/usrtally/ChemCode & Y. Matsuya et al. Phys. Med. Biol. 69, 035005 (2024)

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Electron Track Structure for ARbitrary Target (ETSART) ETSART is a function to simulate the behavior of electrons in arbitrary materials down toenergies as low as a few eV. (only the model for solids is implemented in ver.3.34.)
 The bandgap energy can be input to simulate electronic excitations in solids.

x [nm]

1000-100E-h pair distribution in SiO2

The ε values of semiconductor and phosphors

ETSART can compute the production distribution of electron-hole (e-h) pairs on the order of nanometers(left figure) and the required energy to create an e-h pair (ε value), which is important for evaluating theresponse of the output device (right figure).
Y. Hirata, et. al., Jpn. J. Appl. Phys., 62, 106001 (2023)

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Improvements of [weight window] and [t-wwg]
 A function to navigate particles to regions of interest was developed in [t-wwg] using history counter A function to prevent particles from too-much splitting was introduced in [weight window]
 A function to automatically fine-tune min & max values of xyz-mesh was introduced
History counter was
set in this region
Statistical uncertainties
around this region become
smaller due to the particle
navigation function, while
those in other regions
become higher

neutron20 MeV

Concrete[t-wwg] with particle navigation
Conventional [t-wwg]
Statistical uncertainties of the effective doses calculated with [weight window] created bydifferent [t-wwg] with the same computational time See phits/lecture/advanced/weightB in detail
9[Forced collisions] in thick target
1. Divide the target into 50 segments* and calculate the collision probabilities in each segment
2. Determine the collision point using the probabilities
3. Reproduce nuclear reaction using either nuclear reaction model or nuclear data library*Number of segments can be controlled by nfcseg parameter in [parameters]

without[forced collisions]with[forced collisions]

Fluences of outgoing particles from thick Be target (0.9 cm) irradiated with 20 MeV/n deuteronSee phits/recommendation/neutronsource
10Adjoint mode for charged particles
What is adjoint mode?
••••

Time-inverse particle transport simulation
Useful when you want to know the origin of the particle arrived at a certain location
Used to be applicable only to photon, but a new modality for charged particles has been implemented
Only stopping power and magnetic field can be considered (no nuclear reaction)

Where are the particles
stopped here come from?
（e0 = 0.1, dir= -1）

Proton trajectory in water with magnetic field

Energy distribution of protons when they go out

See /phits/utility/adjoint/charged in more detail11

Automatic download and setup program for JENDL-5
Setup Procedures
1. Select the libraries* to be set up
2. Automatically download and extract theselected libraries
3. Copy address information given in xsdir inthe downloaded library to that used inPHITS**
4. Change the natural abundance databaseused in material expansion according toJENDL-5 neutron libraries

Library Selection Window*Neutron for various temperatures, proton, deuteron, alphaparticle, photo-atomic and photo-nuclear libraries as well as
thermal neutron scattering kernels are available**Neutron library will give priority to the last downloaded
data. Thus, please be careful when you selected theneutron data library with temperature other than 300 K.

Setup program is included in phits/XS folder

12Original text editor PHITS-Pad
1.
2.

Color highlighting of PHITS-specific parameters and input values.
Hint function to assist in making input files.

PHITS-Pad window

Hint window（This can be moved by dragging）
See phits/phitspad/manual13

Visualization of 4D (x,y,z,t) tracks in PHIG-3D
1. Create particle track files using [ t-4Dtrack ] section.
2. Render the track files with PHIG-3D.
 Capable of creating images and videos.
PHIG-3D track display screen（Load the output file）
Example of the section[t-4Dtrack]
file = track.outcolor and line widthof the tracks

So Simple!!

Number of frames
Output images/videos

protonneutronphotonRIetc.

Upcoming Futures
We are planning to …

 Improve the track structure mode Extension of the precise mode applicable to other elements/compounds
 Improvement of coupling modules connecting to material & life sciences Improve affinity to nuclear data library Enables dose calculation and event-generate mode using JENDL-5.0

 Develop user support functions
 Improvement of PHITS-Pad (help function)
 Improvement of RT-PHITS

 Improve accuracy and nuclear reaction model Improvement of JQMD ver. 2.0 to be faster and more accurate Improvement in the evaluation methods for both statistical &systematic uncertainty
 Comprehensive V&V15