1. Recent Improvements and Development Members

1.1. Recent Improvements

Major upgrade features after version 3.02 are described below.

From ver. 3.36, the following function has been implemented, and some bugs have been fixed. (2026/03/31)

• The PHITS manual has been converted from PDF format to HTML format. In the future, the manuals for ANGEL and DCHAIN are also planned to be migrated to HTML format. As part of this preparation, the directory structure under the manual folder has been reorganized, and the DCHAIN manual, previously located in phits/dchain-sp/manual, has been moved to phits/DCHAIN-jp.

• Added the [ Light ] section. It enables generation, transport, and boundary interactions (reflection and transmission) of scintillation light and Cherenkov light.

• Heating calculations using JENDL-5 and other high-energy nuclear data libraries, including charged-particle libraries, are now available through [t-deposit].

• For the nucleus-nucleus reaction cross-section models specified by icrhi, options based on optimized versions of the Tripathi formula (formerly referred to as the NASA formula) and the KUROTAMA model have been added.

• [Outgoing Particle Bias] function has been implemented. This function splits particles resulting from a reaction into two particles. It forces one particle to scatter in a user-defined direction with reducing its statistical weight according to the differential scattering cross-section and the other is scattered without biasing. Currently, this feature only supports Rutherford scattering within the Track Structure function.

• Added the irelax parameter to the [parameter] section, enabling simulation of characteristic X-rays and Auger electrons induced by protons and heavy charged particles.

• The new tally option ph5out has been introduced to export tally results in the PHITS HDF5 file format (ph5). Currently, this option is supported only for the [t-deposit] and [t-wwg] tallies.

• Three new features have been added to PHIG-3D: accelerated rendering of tetrahedral geometries in TetGen and BDF formats, support for visualization of large-scale lattice structures (e.g., voxel phantoms), and video output in WebM format.

• An AI tutor based on the PHITS manual has been developed and made available both as a public tool and for use in user-specific environments.

• The entire source code has been rewritten from Fortran 77 (.f) to Fortran 90 (.f90) using a newly developed Python conversion program. In this process, the source filenames were reorganized for clarity, and some parts of the code were restructured into a folder hierarchy. To assist users in converting their own legacy files (e.g., usrsors.f, usrtally.f) to Fortran 90 format, the conversion program has been provided in the src/f77_to_f90 directory. For details, please refer to src/F77toF90/readme.txt.

• PHITS has been updated to support building with CMake. While the conventional makefiles and Windows project files are still maintained, the use of the CMake-based build system is recommended going forward. This improvement was made with the valuable support of Dr. K. Furutaka from Japan Atomic Energy Agency.

• DCHAIN has been updated to support both distributed-memory and shared-memory parallel computations. In addition, error messages generated during DCHAIN execution are now written to the standard output.

• New reaction identification (ID) numbers have been implemented, enabling the output of detailed reaction types in user-defined tallies and dump mode. For more information, please see Section 6.7.22.

• The dump mode has been introduced to the [T-Track], [T-Deposit], [T-Point], [T-Interact], and [T-DPA] tallies. This function allows for the output of individual particle information (position, direction, energy, reaction ID, etc.) contributing to these tallies. Furthermore, the history counter control now correctly operates within the dump mode.

• A particle cutoff function based on counter values has been implemented. By setting ctmin(1-3) and ctmax(1-3) in the [Parameters] section, users can terminate the tracking of particles that satisfy specific conditions.

• The ihistout parameter has been introduced to output the calculation progress without dividing the simulation into multiple batches.

• New options (e-type = 41, 42, 51, 52) have been introduced in the [Source] section. These allow users to specify source particles with different distributions for angle and energy without utilizing the multi-source function.

• [t-point] calculations using the charged-particle library and the photonuclear data library are now available. Please note, however, that the particles subject to evaluation are still limited to neutrons and photons only.

• A user-defined mirror function has been added. Details are available in Section 5.14. This improvement was carried out with the cooperation of K. Yamamoto of Japan Atomic Energy Agency.

• Introduced the e-unit parameter. Energy mesh can now be specified in units other than MeV, including wavelength (nm, etc.). Currently available in [t-track], [t-cross], and [t-product].

• Lecture materials on how to create PHITS input files using Flair [1] , which is an input file creation support tool for FLUKA, have been added to lecture\fluka-user .

• The iMeVperU parameter, which toggles energy units during tallying, has been renamed to iMeVperN, and its default value has been changed to 1. Consequently, please note that the default energy unit for ions has switched from MeV to MeV/n (kinetic energy per nucleon) for all tallies. This adjustment aims to resolve the unit inconsistency between the [Source] and tally sections.

• The default value of ides in the [parameters] section has been changed from 1 to 0. The ides parameter controls the generation of Bremsstrahlung photons under photon-only transport conditions ( negs = -1 ); with the previous setting ( ides = 1 ), these photons were not generated. This change results in a difference of a few percent in photon deep-penetration calculations.

• The angular momentum of residual nuclei generated by the JAM model is calculated. This improves the accuracy of gamma-ray emission and isomer production by the reactions induced by nucleons with energies of 3 GeV or higher.

• The event generator mode has been improved. When used with e-mode = 3, it enables explicit reproduction of residual-nucleus excitation states and outgoing-particle emission energies.

• When using the high-energy nuclear data library, recoil nuclei are now emitted for elastic scattering when the target nucleus is 1H, 2H, 3H, 3He, or 4He. In addition, for proton-proton (pp) scattering, the calculation is now performed using the model rather than the nuclear data library even if dmax(1) is specified. If you want to use the nuclear data library also for pp scattering, please explicitly set dmax in the [data max] section.

• 9Be production cross sections for protons incident on a 7Li target, which are important for accelerator-based neutron-source designs, have been added to the yield data. Please note that calculated yields using this data may be overestimated above the 7Li(p,2n) reaction threshold (approximately 14 MeV) because the 7Li(p,xn) reaction cross section in JENDL-5 is used as a substitute,

• A new capability has been implemented to evaluate the impact of activation cross-section uncertainties on RI production. A parameter uncfacnd was introduced to scale the yield using the uncertainty ( UNC ) defined in the XS/yield data. By performing calculations with uncfacnd = -1, 0, +1 , systematic uncertainties can be efficiently evaluated using a three-condition approach. This feature enables consistent propagation of nuclear data uncertainties to RI production and subsequent radioactivity calculations.

• The [magnetic field] section has been integrated into the [electromagnetic field] section. You can now define quadrupole magnetic fields and magnetic fields for neutrons within the [electromagnetic field] section. Additionally, an unlimited number of electric and magnetic field maps can now be used.

• The maximum flight step for electrons and positrons in magnetic fields can now be specified using deltg, consistent with other particles. However, if deltm < deltg, deltm will continue to define the maximum flight step to maintain compatibility with previous versions.

• The combination of particle transport using the Track Structure model with electric fields was enabled.

• The algorithm for determining the corresponding mesh in tally calculations has been improved, accelerating simulations involving tallies with a huge number of meshes.

• By setting the size parameter to 0 in the [Mat Name Color] section, the legend for that material will no longer be displayed in the geometry drawn by ANGEL.

• The Dose Voxel Kernel (DVK) mode has been developed and implemented for dose evaluation in nuclear medicine. This mode is intended for use in combination with RT-PHITS. For details, please refer to utility/RT-PHITS/DVKmode. This development was carried out in collaboration with S.S.Tatu of Philippine Nuclear Research Institute during her post-graduate study in Taylor’s University, Malaysia.

• An Excel file, LISMEC [2] , which is useful for biological dose assessment in boron neutron capture therapy, has been added to utility/usranatal/smk_bnct/nucleus_dose. This development was carried out in collaboration with T. Shigehira of Kyoto University.

• When Windows batch files such as phits.bat and dchain.bat are executed, launching PowerShell causes an error in the time-reading function. Therefore, the calculation start time is now output directly from the PHITS executable, and the batch files no longer output time information.

• The following bugs have been fixed: (Note: The first two items occurred only in version 3.35.)

  • A bug that occurred when nucleus names ending in ‘m’ or ‘n’ were defined using the mass number + element symbol format (e.g., 55Mn).

  • An issue where reactions for pions and kaons above 3 GeV were not considered.

  • A bug causing underestimation of secondary particle energies when projectile fission occurs

  • Three issues related to the cosmic-ray source mode: incorrect normalization when using the reg parameter, failure to correctly read solar activity data prior to 1950, and the ground-level correction for muon fluxes not being applied in blackhole mode.

  • An issue where trcl was ineffective in the [Weight Window] and [t-dchain] section.

  • An issue where emission of positrons could not be considered when proj = all for pure electron-capture nuclei (e.g., Ti-44) where only the daughter nucleus undergoes β+ decay.

  • An error that electrons traveling against an electric field are stopped.

  • An issue where user-defined time-varying magnetic fields were ineffective for electrons and positrons.

  • A failure to output the cross section table for a certain MT number using icntl = 1 and inucr=100.

  • Occurrences of “Lost particle” errors under specific conditions in tetrahedral meshes.

  • An error where anatally and restart calculations did not function correctly when unit = 5 was set in [T-Deposit].

  • A bug in [T-Time] where decay particles were not tallied when output = all, and an issue where cutoff particles were incorrectly tallied when output = decay.

  • A bug that occurred when more than 13 materials were specified in the [T-Dchain] section.

  • An issue in INCL that the number of secondary particles emitted per reaction was limited to 20.

  • An error in drawing geometry using the gshow function where cylinders would disappear when a geometry was constructed by overlapping tetrahedral and cylindrical systems.

  • An issue where the default value of gmumul differed from the manual’s description (D=1).

  • An infinite loop occurring when electrons below 1 keV were accelerated by an electric field and exceeded 1 keV.

  • Occasional access violations when applying [Forced Collision] to charged particles.

  • A bug in sumover occurring under the condition of mesh = tet and axis = tet in [T-Deposit].

  • A failure to correctly consider the angular momentum of residual nuclei during the γ-ray de-excitation process.

  • Bugs in [Frag Data] occurring when the target was 1H or when the incident particle was a heavy ion.

[1]

https://fluka.cern/documentation/running/flair-gui

[2]

20. Shigehira et al., Development of Linear Interpolation System for SMK Model Parameters Evaluated from Cellular-Scale Simulation (LISMEC) and its application to BNCT dosimetry. J Radiat Res. (2026). DOI: 10.1093/jrr/rraf075

From ver. 3.35, the following function has been implemented, and some bugs have been fixed. (2025/03/28)

• The activation cross-section of JENDL-5 has been converted into the DCHAIN and ndata formats, and they are stored in the dchain-sp/data and XS/yield folders, respectively. Additionally, in accordance with this update, the default values of ndata in [t-yield] and [t-dchain] have been changed to 2. This improvement was performed under the support of Dr. N. Iwamoto of Japan Atomic Energy Agency.

• A particle navigation function and a low-energy unbiased method have been introduced to [t-wwg]. Furthermore, the introduction of a new parameter named pedestal helps prevent excessive particle splitting.

• The #all command has been added to the [cell] section, enabling the easy definition of the region that serves as the background for particle transport, such as vacuum and air. Consequently, some lecture notes, including lec01 and snowman, have been revised.

• The sum-over values for almost all tallies are correctly derived and made it possible to output their statistical errors.

• When performing two-step calculations using a dump source, a new option has been introduced in the dump parameter so that the dump data IDs are automatically read from the header file. These three improvements were performed under support of NAIS Inc.

• PHIG-3D has been improved to be capable of visualizing the tally results with xyz mesh. Additionally, a rendering function based on the Polygon Boolean method has been introduced, which reduces memory usage (excluding geometries with many curved surfaces). These functions were developed under the support of Dr. S. Ohnishi of National Maritime Research Institute (NMRI).

• A chemical simulation code dedicated to PHITS (PHITS-Chem) has been developed. It enables the calculation of the G values for various types of radiation used in radiotherapy. [3] The code is distributed in utility/usrtally/ChemCode.

• We also developed a function to visualize the kinetics of calculated radicals using PHIG-3D. Furthermore, by adopting a space partitioning algorithm, calculation time has been reduced compared to the first version.

• Sample input files for reproducing neutron sources based on \(\alpha\)-emitters have been added to sample/source/NeutronSource/Precise-model.

• ExPORT-PHITS [4] (Excel Program for Integration of Organ dose rates calculated by RT-PHITS) has been developed and stored in utility/RT-PHITS folder.

• The source code has been revised to be compatible with the new Intel compiler (ifx). In addition, Windows project files for each executable file (single, OpenMP, MPI, and debug version) have been developed and stored in the bin folder. Please see document/Install-IntelFortran-OneAPI-en.pdf in more detail.

• The compiler used to create executable files for Mac has been changed from ifort to gfortran, due to the transition from Intel CPUs to Apple Silicon processors.

• The track structure model for protons and ions, ITSART has been updated. In addition to ionization handled in earlier version, Rutherford scattering and electronic excitation are considered. Moreover, accuracy for ion transport has been significantly improved.

• The mother parameter has been introduced for [t-deposit] and [t-dpa], making it possible to calculate kerma and DPA for each target nucleus. Accordingly, we have significantly modified the recommendation settings and lecture notes for BNCT dosimetry.

• In the cosmic-ray source mode, we have added a mode that generates a source from a plane ( s-type=1 and 2). We have also improved the accuracy in calculating the angular distribution of ground-level muon flux (from 1 to 45 degrees) and the proton flux at low altitudes (above 300 g/cm \(^2\)). Additionally, we have ensured that the Oct. 1989 event is correctly reproduced when environ=4 in SPE mode (previously, the Sep. 1989 event was being reproduced).

• The limitation on the number of elements in a single material when using the EGS mode (previously set to 20) has been removed. In addition, electron and positron transport using EGS in the elements Cm, Bk, Cf, and Es (atomic numbers 96, 97, 98, and 99, respectively) becomes available. These improvements were carried out with the cooperation of Dr. K . Furutaka from Japan Atomic Energy Agency and Dr. Y . Namito and Dr. H . Hirayama from High Energy Accelerator Research Organization.

• Interpolation method using 4-point (cubic) Lagrangian interpolation has been implemented for muliplier function in [multiplier]. This work was performed under the support of Dr. Y . Uwamino and Simplified Shielding Calculation Code Review Working Group, Radiation Science and Technology Subcommittee, Atomic Energy Society of Japan.

• A new function to import tetrahedral-mesh geometry in HDF5 format has been introduced to seamlessly treat data converted from CAD in near future.

• INC-ELF has been improved to calculate \(\alpha\) -induced reactions. This work was performed under the support of Dr. Y . Uozumi and Mr. T . Furuta of Kyushu University.

• Changed the default output format in the [ T-4Dtrack ] tally to the T4D format and added several new parameters.

• Some activation cross section libraries included in DCHAIN have been updated to include the data for \((n,n')\) reactions.

• Added application examples for [User Defined Interaction] (Muon pair production, Neutrino reaction, and Energy cutoff for each region).

• A new parameter, lionprd, has been introduced, allowing control over the types of secondary light ions generated from neutron-induced nuclear reaction simulated using nuclear data library without e-mode. Also, the kerma parameter, which had a similar function to this, has been removed.

• The default setting for checking input file consistency in restart, sumtally, and anatally calculations has been set to OFF ( ireschk=1).

• A new function to check zero-volume tetrahedron has been included in the tetrahedral geometry check itgchk=1. OpenMP parallelization becomes available with tetrahedral-mesh geometry check mode itgchk=1.

• Introduction of file(30) parameter to freely specify the file name of the binary file for tetrahedron geometry with itetra=1 and 2.

• File specification for BDF format tetrahedral-mesh geometry has been changed with the file extension. The binary format has been also revised so the old binary files with itetra=2 needs to be recreated.

• A option to extract some tetrahedrons for tallies with mesh=tet has been introduced. This option is useful to save computational time and file sizes when tally results are requested only part of the tetrahedrons for tetrahedral mesh geometry composed by a large number of tetrahedrons.

• A new parameter primary has been introduced to [T-product] tally. When primary particles remain at the final state of atomic & nuclear reactions, you can choose to include or exclude them.

• In [t-product], part parameter accepts isomers in a format, for example, part=Na-24m In-116n where Na-24m is first isomer and In-116n is second isomer. When nucleus with g is specified (e.g. part=Na-24g), only ground state products excluding isomers are tallied.

• A mesh option mesh=tet becomes available in [weight window] for tetrahedral-mesh geometry. Additionally the mesh option mesh=tet becomes available in [T-WWG] and [T-WWBG] for tetrahedral-mesh geometry. A mesh option mesh=xyz becomes available in [T-WWBG].

• When defining a cone with a vertex using a TRC surface (a truncated conical surface), the value of \(R_2\) is now automatically set to 1.0e-5.

• The anatally function has become applicable to [t-dchain].

• Added two angel parameters, cmap and ndis. This allows selecting colormaps for 2D plots and using discrete color bars.

• The lecture notes for ParaView have been updated and stored in the lecture/advanced/paraview folder. These materials were created with the cooperation of Dr. T . Fujibuchi of Kyushu University.

• The following bugs have been fixed.

  • Deposition energy calculated using kerma approximation for fissile nuclei.

  • Wrong frame transform of neutron emission angle and energy in photo-nuclear reactions has been corrected thanks to assistance by Dr. C'edric Jouanne, Mr. Louis Garnaud of CEA France, and Ms. Nathalie Labonnote of INSTN France.

  • Electron trajectory in electro-magnetic fields.

  • Angular distribution in ground-level muon fluxes for relatively small angle (1–45 deg).

  • 2-D geometry drawing function (seldomly occurred only in version 3.341). - [source] output function in the RI source format in DCHAIN.

  • Nuclear reaction induced by deuterons below 1 MeV/n.

  • Various bugs in track-structure modes.

  • Production in high-energy deuteron and \(\alpha\) particle production above their dmax.

  • Angular distribution in s-type=9 source.

  • Function to read nuclear data for meta-stable nuclides.

  • Event generator mode coupled with dir=-1 neutron source. - [t-cross] with samepage=z.

  • Function to read dump source data written in free ASCII format.

  • Several minor bugs in PHITS-Pad.

  • A bug where flux passed to Dchain was wrongly divided by volume when mesh=tet was selected in [T-Dchain] tally without [Volume] section in the PHITS input file has been fixed.

  • Erroneous unit conversion and formulization in NRF cross section calculation have been corrected thanks to assistance by Dr. Toshiyuki Shizuma of QST.

[3]

Matsuya et al., Phys. Chem. Chem. Phys. (2025). DOI: 10.1039/d4cp04216f

[4]

20. Sato et al., EJNMMI Physics (2025). DOI: 10.1186/s40658-025-00743-6

From ver. 3.34, the following function has been implemented, and some bugs have been fixed. (2024/03/26)

• The installer for Windows has been updated. Please see Section 2.1 for details. Support for 32-bit versions of Windows has been discontinued.

• An automatic download and setup program for JENDL-5 has been developed and included in phits/XS/jendl5 folder. These two improvements were performed under support of AdvanceSoft Corporation.

• The files named natural_abundance_20c.dat (for JENDL-5) and natural_abundance_50c.dat (for JENDL-4) that specify stable isotopes to be expanded when natural elements are specified in the [material] section were included in the data folder. These files are selectively used according to the neutron library written at the beginning of the address file (xsdir.jnd). The mass table included in xsdir.jnd has also been updated. This work was performed under the support of Dr . N. Iwamoto of Nuclear Data Center, JAEA.

• A function to read neutron libraries for meta-stable nuclides has been implemented, though it is applicable only to JENDL-5.

• The executable files of PHITS in the debug mode, which checks for memory violations and uninitialized variables, have been included in the bin folder. They can be used when $DBG=1 is written before the 1st section of the input file.

• Output function of extended statistical indicators has been implemented. In addition to statistical errors, variance of variance (VOV), figure of merit (FOM), and probability density function (PDF) can be output for tally results of [t-track] and [t-point]. Please see Section 6.10 for details. This development was performed by the commissioned work from Nuclear Regulation Authority to Japan Atomic Energy Agency.

• PHITS-Chem code, which allows the simulation of the behavior of radicals generated by water radiolysis, has been included to the package. This code can be used in combination with the [track structure] section (currently only available for electron beams). For details, please see utility/usrtally/ChemCode

• A new track-structure modality, Electron Track Structure model applicable to ARbitrary Targets (ETSART) [5] , has been implemented.

• A new function has been introduced in [t-wwg] to create [weight windows] tuned to reduce statistical errors in specific regions using the concept of the history counter.

• A new parameter deltxyz has been introduced to automatically fine-tune min/max values of xyz-mesh in [weight window] and [t-wwg] when they are defined as integers.

• An adjoint mode applicable to charged particles has been implemented. Please see phits/utility/adjoint/charged folder in more detail.

• A text editor specialized for making PHITS input file (PHITS-Pad) has been developed. Please see phits/phitspad/manual in more detail. This function was developed by Mr. K . Sakamoto and Mr. T . Imaki under the support of Center for Computational Science & e-Systems, JAEA.

• A new tally [T-4Dtrack] has been introduced. Particle track files output by this tally can be loaded in the Particle tracks tab of PHIG-3D, allowing for the creation of images and videos of the tracks. - [User Defined Interaction] section has been introduced, allowing users to relatively easily implement their own interactions into PHITS. - [User Defined Particle] section has been introduced, enabling users to relatively easily implement their own particles into PHITS. Using this feature, it is also possible to modify the properties of existing particles, such as their lifetime or decay patterns.

• The rshow option in tallies for mesh=tet has been implemented.

• A new option to output numbers defined as user-defined variables c \(i\) to file(6)(D=phits.out) has been introduced. The number is output as many times as specified by ncvalout in [paraemters]. It has also been extended to allow definitions up to c999.

• The output parameter of [t-cross] is now automatically determined based on the presence or absence of a-type and e-type.

• Reaction categories ( output) for track-structure modes in [t-interact] have been reorganized. - [Forced collisions] has become applicable to thick targets with variable energy within the target, even when charged-particle nuclear data libraries are used.

• A new parameter mtinfo has been introduced to output the multiplier values used in the multiplier subsection.

• MT numbers 1–3 (total reaction cross sections, elastic scattering cross sections, and inelastic scattering cross sections) are now available in the multiplier subsection even when charged particle or high-energy neutron libraries are used.

• Cross-section output mode ( icntl=1) with inucr=100 has become feasible to output data for all MT numbers (including negative values) that can be defined in the multiplier subsection. In addition, a new parameter epsout has been added to [libout] to generate an image (EPS) file of the output cross section data.

• A sample input file for [frag data] for d-T reaction has been added to phits/sample/fragdata/d-T folder, which was developed based on Nishitani et al. [6]

• New ANGEL parameters ( xdec, xexp, ydec, yexp) have been introduced to specify decimal and exponential types for representing axis values in EPS files.

• The following bugs have been fixed. The first 4 items occurred only after version 3.31 or 3.33.

  • The normalization factor was wrong in the case of factor \(<0\) for [t-deposit] with unit=0.

  • Positrons and their associated annihilation \(\gamma\) -rays were double counted when N-13, O-15, or F-18 was specified in the RI source with proj=all.

  • An error occurred when two or more string variables were used in the same line of an input file.

  • KURBUC mode did not work properly. - [t-interact] did not work properly when ITSART was used.

  • A scattered electron was counted as a produced particle in [t-product] when electron scattering occurs in EGS or track-structure mode.

  • The electron trajectory was shifted slightly after the electrons pass through the magnetic field region.

  • A bug in reflection boundary with tetrahedral-mesh geometry.

[5]

25. Hirata et al., Development of an electron track-structure mode for arbitrary semiconductor materials in PHITS, Jpn. J. Appl. Phys. 62, 106001 (2023).

[6]

20. Nishitani, M. Ishikawa, M.-S. Cheon, S.-H. Hong, R. Rodionov, S. di Sarra, V. Krasilnikov, D. Gin; B. Coriton, “Neutronic simulations of in-vessel neutron calibrations for ITER neutron diagnostics by using simplified ITER model”, J. Fusion Eng. Des. DOI: 10.1016/j.fusengdes.2023.113548

From ver. 3.33, the following function has been implemented, and some bugs have been fixed. (2023/09/01)

• The latest nuclear data library JENDL-5 [7] for neutrons, protons, and deuterons has been included in the PHITS package, while JENDL-4.0/HE and JENDL/DEU-2020 were removed. Consequently, the default values of lib(i) parameter (suffix ID of the primary nuclear data library) have been changed to those for JENDL-5, including photo-nuclear and alpha-particle-induced nuclear reactions. In the case of proton and neutron libraries, the data for approximately 30 nuclei were selected to be included in the PHITS package because the file size of the complete dataset of JENDL-5 is too large - more than 100 GB. Please see “ Section 13.3 Evaluated nuclear data libraries”, in more detail. This work was performed under the support of Dr. C . Konno and Dr. K . Tada of the research group for Research Group for Reactor Physics and Thermal Hydraulics Technology and Dr. S . Nakayama of Nuclear Data Center, JAEA.

• With the partial introduction of JENDL-5, carbon is also expanded to natural abundance ratios. Previously, only carbon was not expanded to natural abundance ratios because JENDL-4 evaluated cross sections as natural carbon.

• A new function to scale the tally output value maximum to be \(factor\) when the factor parameters of corresponding tally is negative, has been implemented.

• A function to consider the detector resolutions has been implemented in [t-deposit2].

• PHIG-3D has been updated to be applicable to input file with user-defined character variable. The opacity of each cell can be defined. These functions were developed under the support of Dr. S. Ohnishi of National Maritime Research Institute (NMRI).

• The maximum character length of the installation folder name (environmental variable PHITSPATH or file(1) parameter) has been extended to approximately 170.

• The default value of iannih has been changed to 1 for avoiding the double count of the contribution from annihilation gamma in the case of proj=all. - jmout has been changed to be automatically set to 1 when [t-dchain] is defined.

• The maximum flight path for charged particles when their energy/angular straggling is considered, deltc, has become independent of the material density in the case that the density is below 1 g/cm \(^3\). Owing to this change, the magnitude of energy/angular straggling in the air (or other gases) becomes slightly smaller in comparison to the previous versions.

• Nuclear reactions are disregarded when the track structure model KURBUC is used in order to precisely reproduce the results of original KURBUC.

• The following bugs have been fixed. Except for the first 2 items, these bugs occurred only after version 3.31.

  • Restart calculation did not work when more than two multiplier subsections were defined in [t-cross].

  • Source locations were wrong when tetra-mesh source ( s-type=24) was used in transformed tetrahedron geometry.

  • CPU time written in phits.out was two-fold overestimated.

  • Access violation occurred when a certain surface in microbody was used (see Table 5.5.4).

  • Access violation occurred when a negative value of nx, ny, or nz was specified in xyz-mesh type source ( s-type=22).

  • Access violation occurred when KURBUC was used. - jmode=-1 did not work in DCHAIN 3.31. - reg parameter in [source] did not work properly when two different values were assigned to the parameters in different multisource.

  • A bug for the geometry with large number repeated lattice structure (\(>\) 10000 in one dimension) showing lost particles has been fixed. Also a bug showing lost particles for tetrahedral-mesh geometry has been fixed.

  • A bug that caused dotted lines to not be displayed on the page after the first page of eps files.

[7]

Iwamoto O, Iwamoto N, Kunieda S, et al. Japanese evaluated nuclear data library version 5: JENDL-5. J Nucl Sci Technol. 2023;60(1):1-60.

In version 3.32, the following bugs have been fixed. Note that the first 4 bugs were occurred only in version 3.31. (2023/05/16)

• A bug in generating neutrons using the RI source function has been fixed.

• A bug that occurred when infl command was used in [surface] and [cell] sections has been fixed.

• A bug in [t-cross] with axis=t has been fixed.

• A bug that rarely occurred when a lot of transformations are used in an input file has been fixed.

• A bug that occurred when dmax(1) was set to below 20 has been fixed.

• A bug that occurred when the incident deuteron or alpha particle energy is exactly the same as their dmax has been fixed.

• A bug in reading neutron data libraries for meta-stable nuclei has been fixed.

• A bug in calculating CPU time has been fixed. This bug was occurred only when the CPU time became longer than 24 hours.

From ver. 3.31, the following function has been implemented, and some bugs have been fixed. (2023/04/07)

• The gamma de-excitation model EBITEM has been upgraded to Ver.2. It uses EGAF(Evaluated Gamma Activation File) to calculate the gamma-rays produced by neutron capture. It also takes into account for atomic de-excitation subsequent to internal conversion. Unless igamma \(\le\) 1 is explicitly specified, Ver.2 is automatically activated.

• A new function to use character variables anywhere in PHITS input file has been introduced. Please see Section 4.5 User-defined character in more detail.

• A new parameter samapage has been introduced for selecting the data types shown in the same page of image output files. Please see samepage in more detail. These two improvements were performed under support of NAIS Inc.

• A new option (inucr=100) to directly output the cross sections contained in nuclear data libraries has been implemented in the cross-section and kerma-factor output mode ( icntl=1). Please see phits/sample/icntl1 in more detail.

• RI source function ( e-type=28,29) has become applicable to self-fission neutron sources.

• Computational time for transporting charged particles has been reduced by storing the maximum nuclear-reaction cross section of charged particles in memory. These three improvements were performed under the support of Dr . N.Furutachi of RIST.

• A new model has been developed in the [t-sed] tally, allowing the calculation of microdosimetric quantitates based on the track-structure mode incorporated in PHITS.

• User Defined Model (PHITS-UDM) has been developed, which allows users to implement their own interactions and particles. Please see https://github.com/sakaki-y/PHITS-UDM for more details.

• A new option itgchk has been introduced to check irregular intersections among tetrahedrons in tetrahedron geometries.

• Anatally function becomes feasible to analyze the results from different tallies. - [t-produce] becomes feasible to score secondary particles generated using nuclear data libraries. These two improvements were performed by Mr. K . Sakamoto and Mr. T . Miura under the support of Center for Computational Science & e-Systems, JAEA.

• A bug that caused electron behavior to be affected by the electromagnetic field even after exiting the field has been fixed. This bug had occurred since version 3.25.

• A bug that occurred when using JENDL4 and other nuclear data (except JENDL-4.0/HE) simultaneously for the same nuclide has been fixed.

• A bug has been fixed in which the thermal motion of target nuclei was not calculated correctly when using [t-point]. This bug was occurred when thermal neutrons were scattered, and the tally result was off by up to 20% in the calculation of the energy-integrated quantities such as the effective dose.

From ver. 3.30, the following function has been implemented, and some bugs have been fixed. (2023/01/10)

• A new option, negs=2, has been introduced for the negs parameter. The maximum energies dmax(12), dmax(13), and dmax(14) for electrons, positrons, and photons are automatically set to 10 TeV when negs=2.

• The gamma-ray emission subsequent to neutron capture is simulated using EGAF(Evaluated Gamma Activation File). Previously, the evaluated data was used for nuclei with atomic number lower or equal to 32(Ge) whereas the theoretical calculation model EBITEM was used for the other nuclei. With this upgrade, PHITS uses the evaluated data for all the nuclei from Z=33 (As) to Z=83 (Bi), U-235 and U-238, in addition to the nuclei up to Ge, to precisely predict gamma-ray spectra of neutron capture reactions.

• A new option of [t-cross] and [t-product] to output the results as a function of LET has been implemented. This option was developed by Mr. K. Sakamoto and Mr. T. Miura under the support of Center for Computational Science & e-Systems, JAEA.

• The areal portion of DCHAIN’s dose conversion factor units, controlled with the idosunit parameter (when using a nondefault value), has been changed to be more intuitive.

• The calculation methods for the ionization and excitation cross sections in ITSART have been improved to reproduce the stopping powers obtained from ATIMA.

• A new option ( inucr=16) has been implemented in icntl=1 to output the stopping power of any ions and material combination.

• The allocation method of the memory for storing the geometry and source information has been changed from static to dynamic. Due to this change, re-compiling PHITS with enlarged mdas parameter is not necessary anymore even when the PHITS simulation consuming extremely large memory size is performed. This change was mostly programmed by Mr. A. Murofushi and Dr. N. Furutachi of RIST.

• Sample input files for the ICRP adult voxel- and mesh-type reference computational phantoms are prepared and included in sample/icrp folder. These input files were created under supervisions of Dr. Akira Endo of JAEA for the voxel phantoms and Dr. Chan Hyeong Kim and Mr. Bangho Shin of Hanyang University for the mesh phantoms. These phantoms are distributed based on the approval from ICRP. You have to cite ICRP Publication 110/145 when you publish the results using the voxel/mesh phantoms, respectively.

• A function to detect geometry errors such as double definition and undefined region has been implemented in PHIG-3D. This function was developed under the support of Dr. S. Ohnishi of National Maritime Research Institute (NMRI).

• ANGEL has been improved to convert a tally output file to the eps file even when the vertical axis of the tally result has exceeds 20 digits. The ANGEL executable file has been updated.

• Instruction for importing CAD geometry into PHITS via tetrahedral mesh has been prepared and included in utility/CADimport folder.

• Two bugs in [t-point] for neutron transport have been fixed. The first one was occurred when \(\gamma\) -rays having anisotropic angular distribution (e.g. 4.4 MeV \(\gamma\) -rays emitted from carbon target) were tallied. In such cases, the intensities of the corresponding \(\gamma\) -rays were overestimated by several orders of magnitudes. The second one was occurred when the secondary neutrons produced by inelastic scattering of non-thermal neutrons were tallied. This bug disturbed the neutron spectra to some extent, but it had almost no influence (less than 1%) on the energy-integrated quantities such as the effective dose.

• A bug in calculating the \(n\) - \(n\) and \(n\) - \(p\) elastic scattering cross sections above 1 GeV in the case of icxnp=1 has been fixed. This bug was introduced in version 3.25.

• A bug in geometry drawing of tetrahedral-mesh geometry with the gshow option has been fixed.

From ver. 3.29, the following function has been implemented, and some bugs have been fixed. (2022/09/12)

• The angular distribution of ground-level muons above 1 TeV has been improved in the cosmic-ray source mode.

• The sampling algorithm of secondary electron energies in the electron track structure mode has been improved.

• A new function to reconstruct dose distribution in carbon ion radiotherapy (CIRT) using treatment planning data has been developed in RT-PHITS. An original graphical user interface (GUI) has been also developed for RT-PHITS, which enables intuitive parameter setting, visualization of geometry of beam devices and the patient body, and evaluation of dose distributions. Please see /phits/utility/RTphits in more detail.

• A new function to detect and show double-defined or undefined regions has been developed in PHIG-3D.

• A new function to tally a result without contribution from the specified particle in part parameter by putting a minus sign before the particle name has been developed.

• Installation and compilation manual of PHITS using OneAPI Intel Fortran Compiler (“ Install-IntelFortran-OneAPI-en.pdf”) has been prepared and included in document folder. Since OneAPI Intel Fortran Complier is freely available and it can build PHITS with much shorter computational time in comparison to gfortran, we recommend to use Intel Fortran for compiling PHITS and stop the support of compiling PHITS using gfortran.

• A Bug in the tallies for calculating history-by-history information, i.e. [t-deposit] with output=deposit, [t-deposit2], and [t-interact] with MorP=Prob, have been fixed. This bug did NOT influence the tally results when the weights of particles were always 1.0. For [t-deposit] and [t-deposit2], only the uncertainties of the tally results were wrong, while both tallied quantities and uncertainties were wrong in [t-interact].

• A bug in generating dump source using Windows OpenMP version has been fixed. This bug did NOT influence the tally results when PHITS calculation properly finished.

• A bug in the RI source mode by setting part=all for alpha emitter has been fixed.

• A bug in the 2D and 3D geometry drawing with gshow with tetrahedral-mesh geometries has been fixed.

From ver. 3.28, the following function has been implemented, and some bugs have been fixed. (2022/05/09)

• [transform] has become effective for ellipse torus and torus surfaces.

• ITSART, the track-structure model for arbitrary materials, considers molecular excitation of water.

• ITSART calculates Rutherford scattering by Thomas-Fermi model, which effectively considers scattering angle cut-off by taking into account for screening by orbital electrons. The scattering angle cut-off specified by ruth_min (0.01 radian by default) is not necessary anymore.

• A bug in reading the new format of thermal scattering libraries has been fixed.

• Several bugs in [t-yield] (the problems in the MPI version, isomer production calculations, and in the cases of axis \(\ne\) chart or dchain) introduced in version 3.27 have been fixed.

• A bug in reading fission yield data in DCHAIN-PHITS introduced in version 3.27 has been fixed.

• Erroneous energy deposition and ion range overprediction, happened when both [t-deposit] and track-structure mode was used, has been corrected.

• Several bugs in the anatally mode have been fixed.

From ver. 3.27, the following function has been implemented, and some bugs have been fixed. (2022/03/22)

• Neutral Kaons decay as K-long (\(K^0_L\)) or K-short (\(K^0_S\)).

• The generalized track structure mode has been upgraded and renamed as ITSART (Ion Track Structure calculation model for Arbitrary Radiation and Targets). ITSART (1) is about 100 times faster than ITS, (2) consumes less memory in thick targets by flipping particle transport sequence, (3) considers Auger electrons and atomic de-excitation X-rays. These improvements are applied to cells whose mID is set as \(-1\) in the [track structure] section.

• A function to read photo-nuclear data libraries in ACE format has been implemented. A new parameter to specify the maximum energy of the photo-nuclear data library, dpnmax, has been introduced in [parameters] section. This development was performed under support of NAIS Inc.

• A function to automatically determine the maximum library energy of each nucleus from the information given in address file (“ xsdir”) has been implemented. In addition, a new parameter lib(i) has been introduced in [parameters] to specify the extension name of the default nuclear data library file for particle type i. Owning to these improvements, it is not necessary to specified [data max] section by users if they want to use all high-energy nuclear data libraries such as JENDL-4.0/HE defined in their xsdir file.

• High-energy event generator mode has been developed, which determines the reaction point using the total cross section contained in the high-energy nuclear data libraries while the information on secondary particles is evaluated using the nuclear reaction models.

• A new parameter mxnuclei has been introduced in [t-yield], which specifies the maximum number of nuclides whose yields are scored in the case of axis=chart or dchain. The default value of this parameter is 3,000, which is much lower than that actually assigned in the previous versions, i.e., 96,288. Consequently, the allocated memory size and computational time are dramatically reduced when [t-yield] or [t-dchain] with large mesh sizes are defined.

• The limitation of the number of particle types ( part) specified in a tally was removed. Note that this limitation in the other sections such as [counter] does not change. Above five improvements were performed under the support of Dr. N. Furutachi of RIST.

• Treatment of thermal scattering libraries has been improved, with support for continuous energy thermal scattering libraries, mixed elastic thermal scattering libraries and libraries containing SANS models such as nanodiamonds. This improvement has been performed under the support of Dr. Jos'{e} Ignacio Marquez Damian at European Spallation Source. More information is available from elsewhere [8]

• The Low-Earth Orbit (LEO) mode has been added to the cosmic-ray source mode. A function to generate the terrestrial cosmic-rays to a certain direction has been implemented.

• A new option ( M= \(\pm\) 3) has been implemented in [transform].

• The parameter iMeVperU became effective in the cross-section output mode ( icntl=1).

• A new option for ignoring the peak from Auger electrons has been implemented in [t-sed].

• The parameter for specifying the source direction such as dir has become effective when the direction of each source particle is not specified in the case of s-type=17 (dump source mode).

• The anatally function has become applicable to all tallies except for [t-cross] with mesh=r-z, [t-adjoint], [t-deposit2], [t-heat], [t-dchain], [t-wwg], [t-wwbg], [t-volume], [t-userdefined], [t-gshow], [t-rshow], [t-3dshow]. This function was developed by Mr. Takamitsu Miura of RIST, and was supported by Center for Computational Science & e-Systems, JAEA.

• The limitation of the shell numbers used in Doppler broadening of Compton scattering energies was extended from 79 to 500. Consequently, iprofr can be set to 1 (default) even when the number of elements per material is large.

• The deuteron nuclear data library JENDL/DEU-2020 in fragdata format was replaced by that in the ACE format. This development was performed under the support of Dr. S. Nakayama of Nuclear Data Center, JAEA. Please refer the paper [9]

• Bugs in [t-yield] occurred when axis=xy (restart and sumtally functions did not work properly) or ndata=3 & e-mode=0 have been fixed.

• The RI source generation function was improved to generate all kinds of radiation from decay (i.e., \(\alpha\) -, \(\beta\) -, and \(\gamma\) -rays) when proj=all is set. (Note that neutrons from spontaneous fission are not considered.) This function was partially developed by Mr. T. Miura of RIST under the support of Center for Computational Science & e-Systems, JAEA.

• A new parameter ndata was added in [counter]. In the case of ndata=2,3 in [t-yield] or [t-dchain], double-counting of yields can be avoided by the [counter] setting.

• A rare bug when many transform matrixes were used in an input file has been fixed.

• A bug that stopped negative pions were not absorbed even in the case of npidk=0 has been fixed. This bug was due to the change of cut-off energy of negative pions from 1 MeV to 1 keV in version 3.13.

• A bug in the cosmic-ray source mode for generating neutrons in the blackhole mode and ground-level muons has been fixed.

• A bug in [elastic option] introduced in version 2.85 has been fixed.

• Several bugs in PHIG-3D have been fixed.

• Electron track structure mode (etsmode) has been slightly modified. We changed the cross sections above 100 keV. Please be careful to simulation results of ionization and excitation events. The results obtained from this version are different from previous ones.

• A bug in the positron transport simulation has been fixed. In the previous versions, some positrons do not emit annihilation gamma-rays when they are stopped in a material.

• Many sample input files have been added to phits/sample folder, such as cosmic-ray sources for various conditions and several neutron sources including those generated by the d-D reaction based on its fragdata prepared by Nishitani et al. [10].

[8]

20. Nishitani, S. Yoshihashi, K. Ogawa, M. Miwa, S. Matsuyama, A. Uritani, “Neutron yield calculation of thin and thick d-D targets by using PHITS with frag data table”, J. Nucl. Sci. Technol. DOI: 10.1080/00223131.2021.1981475

[9]

J.I. Marquez Damian, D. DiJulio, V. Santoro, L. Zanini, G. Muhrer. “ Improvements in thermal neutron scattering data sampling in PHITS”,, UCANS9 Meeting, Riken, Japan (2022).

[10]

https://git.esss.dk/spallation-physics-group/phits-tsl.

[11]

19. Nakayama, O. Iwamoto, Y. Watanabe, and K. Ogata, JENDL/DEU-2020: deuteron nuclear data library for design studies of accelerator-based neutron sources, J. Nucl. Sci. Technol., 805-821 (2021). DOI: 10.1080/00223131.2020.1870010

From ver. 3.26, the following function has been implemented, and some bugs have been fixed. (2021/09/01)

• A function to read nuclear data libraries in ACE format for deuteron and alpha particle has been implemented. Note that [data max] section is not applicable to those libraries. Thus, the nuclear data libraries for all nuclides used in your input file must be prepared even when you want to use the library for a certain nuclide. The libraries can be download from the websites of nuclear data, such as JENDL [11] and TENDL [12] . This improvement has been performed under the support of ASTOM R&D.

• A problem of “ Insufficient virtual memory”, which was observed only in version 3.25, has been fixed. In addition, a parameter to control the relative size of memory space allocated for nuclear data, xsmemory, was introduced in [parameters] section.

• The user defined tally for calculating DNA damage yields contained in /phits/utility/usrtally/DNAdamage has been improved to be capable of estimating the complex DSB yield.

• Track structure mode for arbitrary materials has included Rutherford scattering. This improvement applies to the cells whose mID is -1 in [track structure] section.

• Treatment of escaping protons has been changed in the SCINFUL mode.

• A bug when the dump source mode was used in the OpenMP version has been fixed.

• Calculation method and output unit of arc-DPA in [t-DPA] tally has been revised.

• A bug of unnecessary memory check in the anatally mode has been fixed.

• A bug when the cosmic-ray source mode was used in the MPI version has been fixed.

• Several bugs in PHIG-3D have been fixed.

[12]

https://wwwndc.jaea.go.jp/ftpnd/jendl/jendl-deu-2020.html

[13]

https://tendl.web.psi.ch/tendl_2019/tendl2019.html

From ver. 3.25, the following function has been implemented, and some bugs have been fixed. (2021/07/09)

• The source codes of PHITS have been revised to be compatible with NVIDIA TOOL KIT (former PGI fortran). If you want to compile PHITS with NVIDIA TOOL KIT, please set ENVFLAGS=LinNVIDIA in “ makefile”. This revision was made by Dr. M. Yamaguchi of QST Takasaki and Mr. N. Shirai of Hewlett Packard Japan Inc.

• The memory for containing nuclear data has been changed from static to dynamic one so that PHITS can read extremely large nuclear data without increase mdas parameter. This improvement has been performed under the support of ASTOM R&D.

• DCHAIN-PHITS has been improved to be capable of calculating the fission yields induced by neutrons below 20 MeV. For this improvement, several fission yield data libraries are added in the dchain-sp/data folder. In addition, a new parameter ilchain has been introduced to adjust the maximum chain length independently from the maximum chain number. Please see dchain-sp/manual in more detail.

• A new parameter icxnp has been introduced to select the database of n-p scattering cross sections up to 1 GeV. In the default setting, a new database taken from JENDL/HE-2007 is selected. This improvement has been performed under the support of Dr. D. Satoh of Research Group for Radiation Transport Analysis, JAEA.

• A track structure mode applicable to arbitrary incident ion/material combination has been developed. This mode is applied by assigning mID to be \(-1\) in [track structure] section. By default, this mode assumes that the target comprises a pure element or mixture of pure elements. By specifying the constituent molecules in the [material] section (e.g. chem=CO2), this mode takes into account for the molecular structure of the medium.

• New output options named a-flux and oa-flux have been implemented in [t-cross] for calculating angular differential fluxes.

• The OpenMP parallelization becomes available in the anatally calculation.

• Computational time of PHITS simulation using [t-yield] or [t-dchain] has been dramatically reduced.

• The maximum number of characters to be read in a line of xsdir has been extended from 80 to 130.

• The evaluated high-energy nuclear data libraries JENDL-4.0/HE for twenty-two nuclides stored in the PHITS package have been replaced with the files officially released by the research group for Reactor Physics and Standard Nuclear Code System, JAEA. The proton data files of \(^6\) Li and \(^7\) Li were added in the package. Please see Section 13.3 for more detail. This work and the modification of PHITS related with reading files were performed under the support of Dr. C. Konno of the research group for Reactor Physics and Standard Nuclear Code System.

• A bug in reading proton-Li data of JENDL-4.0/HE has been fixed.

• A bug when spatial size of xyz mesh is too large in [weight window] setting has been fixed.

• A bug in controlling particle weight when a source with weight \(\ne\) 1 is generated in a void cell has been fixed.

• A bug that rarely causes double defined region when a microbody surface is rotated has been fixed.

• Several bugs in PHIG-3D have been fixed.

From ver. 3.24, the following function has been implemented, and some bugs have been fixed. (2021/03/12)

• Estimation of doses from induced-activities by connecting calculation of PHITS using [t-dchain] with xyz mesh \(\to\) DCHAIN-PHITS \(\to\) PHITS becomes feasible. Please see /phits/dchain-sp/sample/3-step_dose_xyz in more detail. This function was partially developed by Mr. T. Miura of RIST under the support of Center for Computational Science & e-Systems, JAEA.

• The concept of history-counter, which is the maximum counter value of all particles generated in one history, has been introduced in tallies. When you define a constraint using this history-counter, you can tally your interested events selectively by tracing back to the generation of their source. Please see /phits/sample/misc/history_counter in more detail. This function was developed under the support of Dr. N. Furutachi of RIST.

• Functions of independently controlling source generations (ibatch in [source]) and summarizing tally results ( itall=4) of each batch have been implemented. Using these functions, you can reduce the computational time when you need to run many simulations with different source conditions. These functions were developed under the support of Dr. N. Furutachi of RIST.

• A function to output the line number, the subroutine and file names where error or warning message is written in the source program has been implemented. This function is activated by setting ierrout=1 in [parameters]. This function was developed by Mr. T. Imaki under the support of Center for Computational Science & e-Systems, JAEA.

• Parameters and equations become usable in the definition of multiplier subsections, except for equations using brackets.

• Sample programs of user-defined anatally for calculating the biological dose for targeted radionuclide therapy and the dose-mean LET have been provided in the /phits/utility/usranatal folder.

• [frag data] files of JENDL Deuteron Reaction Data File 2020 (JENDL/DEU-2020) [13] were contained in /phits/XS/fragdata/. Deuteron-induced reactions on Li \(^{6,7}\), Be \(^9\), and C \(^{12,13}\) can be described well by the data files. This development was performed under the support of Dr. S. Nakayama of Nuclear Data Center, JAEA. Please refer to the paper [14] in your publication using the data files. Furthermore, a sample input file for an accelerator-based neutron source using the data file was contained in /phits/recommendation/NeutronSource.

• RT-PHITS (RadioTherapy package based on PHITS) has been developed by introducing various new functions into DICOM2PHITS, such as a module for converting PET-CT data to the [source] section. Please see /phits/utility/RTphits in more detail. This development was performed under the support of Dr. Y. Koba, Dr. S. Yonai, Dr. S. Matsumoto, Dr. W. Chang of QST, and Dr. T. Watabe and Mr. H. Sasaki of Osaka University. freely use, change, distribute, and relicense to third parties.

• Several bugs are fixed, including the problems in cosmic-ray source mode, [frag data], electron transport in complex electro-magnetic fields. Bugs related to OpenMP and multiple lattice definitions introduced in version 3.23 are fixed. However, a bug in reading dump source file occurred in the Linux-OpenMP version has not been fixed yet.

• Bugs in sample user-defined tallies included in /phits/utility/usrtally have been fixed. These bugs occured only after version 3.22. In addition, your own user-defined tally may not work in tandem with the latest PHITS. In that case, please revise your user-defined tally program by referring /phits/utility/usrtally/readme-en.docx.

[14]

https://wwwndc.jaea.go.jp/ftpnd/jendl/jendl-deu-2020.html

[15]

19. Nakayama, O. Iwamoto, Y. Watanabe, and K. Ogata, JENDL/DEU-2020: deuteron nuclear data library for design studies of accelerator-based neutron sources, J. Nucl. Sci. Technol., 805-821 (2021). DOI: 10.1080/00223131.2020.1870010

[16]

19. Ohnish, Gxsview: Geometry and cross section viewer for calculating radiation transport, SoftwareX, 14, 100681 (2021).

From ver. 3.23, the following function has been implemented, and some bugs have been fixed. (2021/01/12)

• A new source option for reproducing the cosmic-ray environments in space and in the atmosphere has been implemented. Please see the source section for more detail.

• The user-defined anatally function has been implemented for analyzing multiple tally results, using a user-defined program written in usranatal.f. As examples, biological dose calculation programs based on the stochastic microdosimetric kinetic model [15] have been developed. Please see Section 6.9.1 and the utility/usranatal folder in more detail.

• The photon reaction cross sections can be outputted using icntl=1. When ipnint=1,2, processes of photo-nuclear reactions are outputted.

• The maximum number of isotopes defined in [material] has been changed from 92 to 300.

• A warning message is shown when a particle is split into more than 10 particles by importance or weight window functions.

• The athermal-recombination-corrected dpa(arc-dpa) can be outputted using idpa=1 in the [t-dpa] section. Details are in the paper [16] .

• DCHAIN-PHITS has been improved by introducing several new parameters and increasing the maximum number of materials in an xyz mesh from 10 to 100. Please see dchain-sp/manual in more detail. Furthermore, the new main DCHAIN reference paper [17] has been published.

• DCHAIN-PHITS has been improved by introducing several new parameters and increasing the maximum number of materials in an xyz mesh from 10 to 100. Please see dchain-sp/manual in more detail. Furthermore, the new main DCHAIN reference paper [18] has been published.

• Memory assignment of lattice strucutre data of geometry has been changed to dynamical allocation. Owing to this improvement, the re-compiling of PHITS to extend the memory space becomes not necessary for the calculation with a large memory voxel data.

• A bug when two (or more) lattice structures are used in an input file has been fixed. This bug occurs only in version 3.22.

• A bug in calculating particle trajectories in the magnetic or electromagnetic fields defined in the data list type with non-uniform meshes has been fixed.

[17]

20. Sato and Y. Furusawa, Radiat. Res. 178, 341-356 (2012).

[18]

25. Iwamoto, S. Meigo, and S. Hashimoto, J. Nucl. Mater. 538 (2020) 152261. https://doi.org/10.1016/j.jnucmat.2020.152261

From ver. 3.22, the following function has been implemented, and some bugs have been fixed. (2020/10/09)

• A new option has been introduced in the phase-space source based on accelerator emittance ( s-type=11). Please see the source section for more detail. This development was performed under the support of Dr. Y. Sakaki of National Institutes for Quantum and Radiological Science and Technology (QST).

• A bug for ignoring the relativistic theory in the calculation of particle trajectory using magnetic field map has been fixed. This bug fix was supported by Mr. N.Tokunaga of Kyushu University.

• A bug in drawing the geometry with cell number has been fixed. This bug occurs only in version 3.21.

From ver. 3.21, the following function has been implemented, and some bugs have been fixed. (2020/09/14)

• A function to use the stopping power of liquid water, graphite, and dry air given in ICRU90 has been developed. For protons and carbon ions, the dedx files for those stopping powers were prepared and contained in data/dedx. For electrons, the database of the density correction factors used in the evaluation of ICRU90 was prepared, and it can be used by setting epstfl=1 in the [parameters] section. Please see utility/icru90 in more detail. This development was performed under the support of Dr. Y. Namito of KEK and Dr. M. Shimizu of AIST.

• A new function for calculating the response function of an organic scintillator based on SCINFUL-QMD [19] has been developed. Please see utility/usrtally/scinful-qmd in more detail. This development was performed under the support of Dr. D. Satoh of Research Group for Radiation Transport Analysis, JAEA.

• An algorithm for adjoint Monte Carlo simulation has been implemented for efficiently estimating the photon fluences in a small region from sources distributed in a large area. Please see the adjoint-mode section as well as utility/adjoint in more detail. This development was performed under the support of Dr. A. Malins of the Center for Computational Science & e-Systems, JAEA.

• A function to output cross sections and kerma factors used in PHITS has been developed as a part of icntl=1. Please see utility/icntl1 in more detail.

• Iwamoto’s fission model has been implemented for fission of sub-actinides (nuclides with atomic number less than 89). This function was developed under the support of Dr. H. Iwamoto of Japan Atomic Energy Agency, Research Group for Nuclear Transmutation System. For future improvement of the actinide fission model, the fission barrier table Fission_barrier_table_PhysRevC_91_024310.dat [20] is placed in phits/data.

• Gamma evaporation model EBITEM is upgraded to use up-to-date RIPL (Reference Input Parameter Library)-3 [21] nuclear structure data placed in phits/data/RIPL. In the old versions, the ENSDF nuclear structure data taken in 2012 was built into the executable. The merits of this upgrade are improvement of calculation accuracy, downsizing of the PHITS executable, saving runtime memory requirements, and reduction of compilation time. The new version of EBITEM is automatically used without any extra operations.

• DCHAIN-PHITS has been improved to output the statistical uncertainties by propagating those of the PHITS simulation. In addition, the mesh option mesh=tet becomes available in [t-dchain].

• Analysis function using autorun was improved to estimate systematic uncertainties of results of [t-deposit] ( output=dose). Furthermore, this function can be applied for two (or more) tally sections written in an input file. This function was developed by Mr. Takamitsu Miura of RIST, and was supported by Center for Computational Science & e-Systems, JAEA.

• An option to select share/non-share of tally variables for OpenMP shared-memory parallel computing has been implemented. A setting to reduce required memory by sharing tally variables among multi threads was chosen in older version of PHITS. However there were cases that computational speed became slow due to a bottle neck of a process required to prevent memory corruption. Thus a new option to select share/non-share of tally variables are introduced.

• A new parameter gsline was introduced in the [parameters] section to control gslat parameter in each tally in a lump. In addition, new options for gslat were added.

• A new parameter icells was introduced in the [parameters] section to read and write binary files of the entire [cell] section for reducing the computational time for reading complex geometry.

• For PHITS simulation using voxel data, echo of the voxel data is excluded from the input echo in the phits.out file to reduce output data file size and computational time. By setting an option ivoxel=3 in the [parameters] section, you can obtain the voxel data echo as before.

• A new parameter ichkmat has been introduced to check material numbers and densities of each cell when different densities are defined for a given material number. When incorrect drawing of the geometry by gshow option occurs, this option may work well. Note that it increases the loading time of complex geometry with a lot of cells.

• Bugs in the use of proton nuclear data library have been fixed. In addition, a new parameter epseudo to control the energy for calculating pseudo reaction cross section has been introduced in [parameters] section. These revisions were performed under the support of Dr. N.Furutachi of RIST.

• Bugs in the electron motions in magnetic fields have been fixed. A bug in the consideration of the magnetic field map for z-direction has been fixed. A bug in reading proton nuclear data libraries has been fixed. If you used these functions in your PHITS simulations, we recommend to re-perform them. A bug in t-deposit tally for tetrahedral-mesh geometry using the next region material by mistake.

[19]

4. Satoh, T. Sato, N. Shigyo and K. Ishibashi, SCINFUL-QMD: Monte Carlo based computer code to calculate response function and detection efficiency of a liquid organic scintillator for neutron energies up to 3 GeV, JAEA-Data/Code, 2006-023 (2006).

[20]

Peter Moller, Arnold J. Sierk, Takatoshi Ichikawa, Akira Iwamoto, and Matthew Mumpower, Fission barriers at the end of the chart of the nuclides, Phys. Rev. C 91, (2015) 024310. DOI: 10.1103/PhysRevC.91.024310

[21]

18. Capote, M. Herman, P. Oblozinsky, P.G. Young, S. Goriely, T. Belgya, A.V. Ignatyuk, A.J. Koning, S. Hilaire, V.A. Plujko, M. Avrigeanu, O. Bersillon, M.B. Chadwick, T. Fukahori, Zhigang Ge, Yinlu Han, S. Kailas, J. Kopecky, V.M. Maslov, G. Reffo, M. Sin, E.Sh. Soukhovitskii and P. Talou, Reference Input Parameter Library (RIPL-3), Nuclear Data Sheets, 110, Issue 12, (2009) 3107-3214

From ver. 3.20, the following function has been implemented, and some bugs have been fixed. (2020/03/19)

• Proton (\(E<300\) MeV) and carbon ion (\(E<10\) MeV/n) track structure codes, KURBUC [22] , have been implemented in this version of PHITS code system. The implementation was performed under collaboration with Prof. Hooshang Nikjoo and Dr. Thiansin Liamsuwan who developed the KURBUC codes. The copyright of KURBUC codes belongs to Prof. Hooshang Nikjoo, and its source code is not included in the PHITS package.

• A function to consider the photon-induced muon-pair production has been implemented. This function was developed under the support of Dr. Y. Sakaki of KEK. See the paper [23] in more detail.

• A new section [repeated collisions] has been implemented to improve the statistics of rarely produced secondary particles. Please see Section 5.22 for more details. This function was developed under the support of Dr. H. Iwamoto of Japan Atomic Energy Agency, Research Group for Nuclear Transmutation System.

• A new parameter iangform has been introduced in [T-Cross] section to choose the reference for formed angle in a-type mesh. In addition to the normal vector to the surface ( iangform=0), x-axis ( iangform=1), y-axis ( iangform=2) and z-axis ( iangform=3) can be chosen.

• A new option opt=5 in [frag data] has been introduced: pointwise data of differential cross sections can be read by this option.

• A function to read the stopping power of each material from the user-supplied table has been implemented. As for the sample data, the stopping power of protons and \(\alpha\) particles in various materials calculated by PSTAR and ASTAR [24] were prepared and included in the phits/data/dedx folder. This development was performed under support of NAIS Inc.

• A new pseudo-random number generator xorshift64 has been implemented. This generator was used in the default settings. The period length of random numbers was extended from \(2^{46}\) to \(2^{64}-1\) by the new generator.

• 2-dimensional geometry drawing function, gshow, has been improved to properly depict complicated geometry defined by voxel or tetrahedron. This improvement was performed under support of NAIS Inc.

• Several activation cross section libraries used for DCHAIN-PHITS have been developed, and their hybrid library has been selected as the default library. In addition, the decrease of target nuclides due to nuclear reaction has been automatically considered by setting the default values of itdecs and itdecn to 1. Please see Section 7.15 for more detail. This development was performed under the support of principal researcher C. Konno of Japan Atomic Energy Agency, Research Group for Reactor Physics and Standard Nuclear Code System.

• A bug of providing particle energy in MeV/n instead of MeV/u with ATIMA was fixed. Owing to this revision, the range of charged particle slightly changed

• approximately 1% at the maximum. In addition, the unit of ion energy in PHITS is not MeV/u but MeV/n, and the PHITS manual as well as input echo were revised accordingly.

• The power index of the Maxwellian energy distribution source (e-type=3, 7) has become changeable, and its default value was set to 0.5. Note that the former versions of PHITS set the power index to 1.0, but they could not properly reproduce the Maxwellian distribution.

• A new function was implemented to estimate systematic uncertainties of tally results based on analysis variance (ANOVA). Effects caused by errors of input information can be estimated by this function. Furthermore, script files autorun (autorun.bat & autorun.sh) were improved for analysis function in PHITS. The scripts successively execute PHITS by slightly varying input values. Please see Section 6.9.2 for more detail. This function was developed by Mr. Takamitsu Miura of RIST, and was supported by Center for Computational Science & e-Systems, JAEA.

• Documents for the connection calculation between PHITS and FLUENT were made. See files in /phits/utility/FLUENT in detail.

[22]

Uehara S, Nikjoo H, Goodhead DT, 1993, Cross sections for water vapour for Monte Carlo electron Track structure from 10 eV to 10 MeV region. Phys Med Biol 38: 1841-1858; Liamsuwan T, Uehara S, Emfietzoglou D and Nikjoo H 2011, Physical and biophysical properties of proton tracks of energies 1 keV to 300 MeV in water, Int. J. Radiat. Biol. 87 141-60; Liamsuwan T and Nikjoo H 2013 A Monte Carlo track structure simulation code for the full-slowing-down carbon projectiles of energies 1 keV u \(^{-1}\) - 10 MeV u \(^{-1}\) in water, Phys. Med. Biol. 58 673-701

[23]

Y . Sakaki et al., Implementation of muon pair production in PHITS and verification by comparing with the muon shielding experiment at SLAC, Nucl. Instr. & Meth. A 977, 164323 (2020).

[24]

https://www.nist.gov/pml/stopping-power-range-tables-electrons-protons-and-helium-ions

From ver. 3.17, the following function has been implemented, and some bugs have been fixed. (2019/10/29)

• A new option foamout=2 to output the tetrahedral-mesh tally results in csv format has been implemented.

• The bug in the [t-deposit] calculation using EGS5 was fixed. This bug was due to uninitialization of a certain variable in PHITS, so it occasionally causes a serious influences on the tally results, but in most case not.

• The calculation procedures for sum over in many tallies have been revised.

• The calculation procedures for sum over in many tallies have been revised.

• The parameters used in the biological dose calculation using usrdfn2.f were changed from those given in T.Sato et al. Radiat. Prot. Dosim. 143, 491-496 (2010) to T.Sato et al. Radiat. Res. 171, 107-117 (2009).

From ver. 3.16, the bug for sangel parameter has fixed. The other bug in ver. 3.15 that [t-track] tally does not output _err files has also been fixed. (2019/09/26)

From ver. 3.15, the following bugs have been fixed. (2019/09/12)

• A bug that [t-deposit] overestimates contributions of the energy cut-off in EGS5 has been fixed. Furthermore, another bug when using EGS5 and lattice structure has been fixed. The former and latter bugs occurred from version 3.13 and 3.10, respectively.

• A bug regarding the function when setting itall=3 has been fixed. Segmentation errors occurred depending on input files. This bug occurred from version 3.13.

• A bug of DCHAIN, which occurred only in version 3.14, has been fixed.

From ver. 3.14, the following functions have been implemented, and some bugs have been fixed. (2019/08/18)

• DCHAIN-SP has been improved in terms of the following two features; (1) several neutron activation libraries and decay-data libraries have been developed based on the latest evaluated data, and (2) statistical uncertainties of the induced activities can be evaluated considering those of the production yields calculated by PHITS. Owing to these improvements, some parameters have been added to [t-dchain] section (see Section 7.15 in detail). The new version of DCHAIN will be called DCHAIN-PHITS to be distinguished with the previous versions.

• A new function to calculate DNA damage yields has been developed, using the track structure mode and user-defined tally. Their sample data are contained in “/phits/utility/usrtally/DNAdamage.”

• A new function to calculate DNA damage yields has been developed, using the track structure mode and user-defined tally. Their sample data are contained in phits/utility/usrtally/DNAdamage.

From ver. 3.13, the following functions have been implemented, and some bugs have been fixed. (2019/08/02)

• The default value of the cut-off energy for proton, pion, muon, and ions has been decreased from 1 MeV/n to 1 keV/n.

• A new source type ( s-type=26) has been introduced to define a surface source which generates source particles on the surface(s) that has/have been pre-defined in the [surface] section.

• A new option, itall=3, has been implemented to plot the trend of tally results and their statistical uncertainties for each batch with the ongoing PHITS calculation. This option is available only for [t-track] and [t-point] at this moment.

• A new parameter, istdcut, has been introduced to the [parameter] section. It enables the termination of the tally calculations of which the statistical uncertainties have reached the stdcut setting. This function is particularly useful when the types of tallies which consume much longer computational time, such as [t-point] and [t-sed], are written in the same input file with other tallies. Another new parameter, istdbat, has been introduced to inactivate stdcut at the early stage of the PHITS simulation.

• In stopping power calculations using ATIMA, the ionization potential of water is expected to automatically adjust to 75 eV. However, this function was valid only when the material of water was explicitly specified by the isotope 1H, i.e. material consists of natural abundant hydrogen is not treated as water in this particular respect. We modified the program, so that the material of water which is defined by naturally-abundant hydrogen isotopes, such as in the format of H 2 O 1 and H -0.1111 O -0.8889, is now regard as water for stopping power calculations. Owing to this modification, the ranges of charged particles in water increase slightly (less than 1% in most cases) compared to the results obtained from the previous versions. The valid condition of ih2o parameter has been also revised in the same way.

• Some bugs have been fixed, such as ignorance of stdcut in the MPI version, strange behavior of particles when mirror surfaces are used in lattice structure, and a rare bug in EGS5.

From ver. 3.12, the following functions have been implemented, and some bugs have been fixed. (2019/06/20)

• The new parameters cnt(1), cnt(2), and cnt(3) have been introduced in [source] section to specify the initial counter values for each multi-source subsection <source>. The maximum number of <source> subsections is extended from 200 to 500.

• A function to consider the decrease of target radioactive nuclides due to nuclear reactions has been implemented in [t-dchain]. DCHAIN has also been revised in correspondance to the [t-dchain] improvement. Note that former versions of DCHAIN cannot read the outputs from the improved [t-dchain].

• The itall = 1 option has become available in the Windows OpenMP version of PHITS.

• Some bugs regarding the FLUENT-PHITS coupled calculations have been fixed, including the incorrect translation of the material densities between FLUENT and PHITS.

From ver. 3.11, the following bugs have been fixed. (2019/05/16)

• The bug of MPI parallel calculations with tetrahedral-geometry stopped abruptly in ver. 3.10 has been fixed.

• The bug that the magnetic field maps given in r-z grid ( type = -2 or -4) cannot be properly considered has been fixed.

• Annihilation photons are double counted in the RI source generation function when the production of both positron and photon are considered. To avoid the problem, a new parameter iannih has been introduced to exclude the annihilation photons in the case of proj = photon.

From ver. 3.10, the following functions were implemented, and some bugs were fixed. (2019/03/13)

• Procedure for coupling PHITS with thermal analysis software such as ANSYS Fluent is established. For this purpose, a function to read tetrahedral-mesh geometry written in bulk-data format of NASTRAN is implemented. A new mesh option, mesh=tet, is introduced in [t-track], [t-deposit], [t-yield], [t-product], and [t-dpa] to output the tallied quantities in each tetrahedral mesh. Field-data format used in OpenFoam, which can be directly read by thermal analysis software, has become selected as an output format.

• As a part of the improvements for coupling with thermal analysis software, a new option, unit=5, is introduced in [t-deposit] to output the deposition energy in J/m \(^3\) /source.

• Sample files for using high-energy nuclear data library JENDL-4.0/HE are provided in the PHITS package. Please see phits/recommendation/jendlHE in more detail.

• Sample files for using the high-energy nuclear data library JENDL-4.0/HE are provided in the PHITS package. Please see phits/recommendation/jendlHE in more detail.

• A nuclear reaction model to handle the reactions by electron-, mu-, tau-neutrino and their antiparticles up to 150 MeV of incident energy is incorporated. Neutrinos can interact with orbital electrons, \(^1\) H, and \(^2\) H whereas the nuclei heavier than \(^2\) H are currently out of the range of this model.

• INC-ELF, an intra-nuclear cascade model developed by Kyushu University, is updated to consider collective excitation of the target nucleus and to precisely calculate charged particle emission barriers.

• Electron track-structure mode is improved to consider the production of Auger electrons.

• User-defined energy resolution function has been implemented to [T-deposit] in order to reproduce energy resolution which cannot be realized by dresol and dfano. Users can define the functional forms of energy resolution in usresol.f, which is activated by defining negative dresol. As a sample, the default usresol.f contains a numerical model proposed by Meleshenkovskii et al. to reproduce asymmetric peaks of a CdZnTe detector.

• A new option, gshow=5 and [t-gshow] with output=10, is introduced to visualize the geometry in the pixel format. This option is useful for properly visualize the geometries with fine structure such as voxel and tetrahedral phantoms.

• Time for reading lattice structure such as voxel phantom data is reduced by introducing compressed format.

• Some parameters in the muonic atom cascade program have become adjustable.

• The third user-defined function, usrdfn3.f, is introduced for weighting the results of [t-deposit]. The default program of usrdfn3.f can convert the absorbed dose to the water equivalent dose, which is frequently used in medical physics.

• Remaining batch number has become adjustable using “ batch.out.”

• Remaining batch number has become adjustable using batch.out.

• Deposition energies in the cells with the same ID but placed in different lattice coordinates can be separately analyzed in the case of [t-deposit] with output=deposit.

• Nuclear data libraries containing more than 1000 \(\gamma\) -ray spectra such as the latest version of ENDF and JEFF have become acceptable in PHITS.

• The fixed charge mode, ifixchg=1, is introduced for calculating the stopping power of particles with a certain charge state. Note the charge exchange reaction has not been implemented yet, so the fixed charge mode is appropriate only when target material is extremely thin at this moment.

• Several bugs are fixed, including the problem in positron transport when emin(12) is specified without specifying emin(13), and that in electron and positron transports in the magnetic field defined at a lattice structure.

From ver. 3.08, the following changes have been made. (2018/08/20)

• The user-defined activation cross section data can be used in the [t-yield] and [t-dchain] sections. This new function was supported by the R&D program entitled Reduction and Resource Recycling of High-level Radioactive Wastes through Nuclear Transmutation in the Impulsing Paradigm Change through Disruptive Technologies Program (ImPACT).

• For RI sources, characteristics x-ray and internal conversion electron are now considered.

• Tetrahedral geometries that are converted from CAD can now be used, even when the surface of tetrahedron does not perfectly match the boundary surfaces.

• The parameters (c1-c99) specified in the input file can be used in the user-defined source file (“ usrsors.f”).

• The parameters (c1-c99) specified in the input file can be used in the user-defined source file (usrsors.f).

• For cylindrical sources ( s-type=1), a few bugs, such as the bug occurring when a source particle is sampled between 0 and r1 with the setting of r0=r1, have been fixed.

From ver. 3.07, mesh=xyz became available in [weight window] for EGS5. Conversion coefficients for soft error rates on semiconductor devices were added to default data of [multiplier]. In addition, some bugs for JAM were fixed. (2018/07/05)

From ver. 3.06, the following functions were implemented, and some bugs were fixed. (2018/05/29)

• By defining igamma as negative, Doppler effect owing to the motion of the emitter nuclei is disregarded. Specific gamma-rays are observed as mono-energetic peak in the energy spectrum.

• GEM Ver.2 including nucleon-gamma emission competition was developed. This version is available by setting ngem=2 in [parameters] section.

• New format of [transform] was implemented to define rotation around z,y,x axes simply.

• The distributed-memory parallel computing using a MPI protocol became available on Windows. This development was performed under support of NAIS Inc.

From ver. 3.05, the following functions were implemented, and some bugs were fixed. (2018/03/14)

• The function to calculate the deposition energy using kerma approximation, which used to be implemented only in [t-heat], became available in [t-deposit]. Necessity of the use of kerma approximation in the energy deposition calculation is automatically judged based on the status of e-mode and negs specified in [parameters] section. Owing to this improvement, we recommend to use [t-deposit] instead of [t-heat] in all situations of deposition energy calculations. - [t-deposit] with output=deposit can be used in the case that weight is not always 1 unless weights of energy depositing particles change within one history. Then, this mode works in the cases that you set s-type=9 and dir=-all in [source] section, or you use [forced collisions] for neutral particles.

• The graph style for [t-cross] with axis=z is changed from histogram to dot & line.

• Specification of z-type=1 and nz=0 is allowed for [t-cross] to calculate fluences of particles passing through a certain surface.

• Numbers of delta-rays produced by ions (including protons) and knock-on electrons produced by electron scattering can be separately calculated in [t-interact] section. In addition, they can be distinguished in [counter] section too.

• RI source function was improved to produce Auger electrons even when the Auger electron spectrum data are not included in RIsource.ack.

• A bug in [t-product] in the case of iMeVperu=1 was fixed.

From version 3.04, the probability density of the number of interactions by individual history can be outputted from [t-star]. The number of interactions occurred in the track-structure mode can be also counted in the tally. In addition, the tally name was changed to [t-interact] in order to explicitly state that it is the tally for counting the number of interactions, though the former name [t-star] can still be accepted. (2018/02/16)

From ver. 3.03, the following functions were implemented, and some bugs were fixed. (2018/02/01)

• A new function to generate source particles from tetrahedron geometry was implemented.

• mesh = xyz became available in [weight window] and [t-wwg] sections.

• Coefficients depending on particle type can be defined in [multiplier] section, using part parameter. Owing to this improvement, several types of radiation doses can be directly calculated using pre-defined [multiplier] sections. - [t-deposit] with output=deposit can be used in the case that source weight is not 1.

• A bug in [t-deposit] in the cases of output=deposit, dresol \(\ne0\), and part \(\ne\) all was fixed.

• A bug in the range calculation of charged nuclei in some tallies when iMeVperu=1 was fixed.

From ver. 3.02, the following functions were implemented, and some bugs were fixed. (2017/12/01)

• New parameters nudtvar and udtvar \((i)\) were introduced for [t-userdefined]. After variables udtvar \((i)\), (\(i=1,\cdots,\) nudtvar) was set in an input file, these can be used in subroutine usrtally. There is no upper limit of the number of udtvar \((i)\) unlike udtpara before ver. 3.01. udtpara can be also set after this version.

• New options were implemented for the unit of [t-let] and [t-sed].

• Position of the source generation was adjusted to just on the spherical surface for s-type=9 with dir=iso. This revision influences only when some materials are placed outside the source sphere.

• A bug related to [counter] section was revised. Before this revision, occurrence of atomic interactions were ignored in calculating counter when negs was set to -1 (only photon transport mode).

• A bug in the calculation of the restricted stopping power when \(\delta\) -rays are generated by [delta ray] was fixed.

• The bug in the calculation of angular straggling using nspred = 2 was fixed. This bug was introduced in PHITS2.96, and calculation results for charged particle beam using the versions between 2.96 and 3.01 might be strange.

1.2. Development members

• Tatsuhiko Sato, Yosuke Iwamoto, Shintaro Hashimoto, Tatsuhiko Ogawa, Takuya Furuta, Shinichiro Abe, Takeshi Kai, Yuho Hirata, Takuya Sekikawa, Seiki Ohnishi, Norihiro Matsuda, and Lan Yao: JAEA, Japan

• Yusuke Matsuya: Hokkaido University, Japan

• Hiroshi Iwase, Yasuhito Sakaki, and Kenta Sugihara: KEK, Japan

• Nobuhiro Shigyo : Kyushu University, Japan

• Hunter N. Ratliff : Western Norway University of Applied Sciences, Norway

• Lembit Sihver : The University of Texas Rio Grande Valley, USA

• Koji Niita : RIST, Japan

The following members also contributed to the development of PHITS

• Tsai Pi-En, Hiroshi Nakashima, Tokio Fukahori, Keisuke Okumura, Tetsuya Kai, Shusaku Noda, Yukio Sakamoto, Hiroshi Takada, Shin-ichiro Meigo, Makoto Teshigawara, Fujio Maekawa, Masahide Harada, Yujiro Ikeda : JAEA, Japan

• Satoshi Chiba : TITech, Japan

• Takashi Nakamura : Tohoku Univ., Japan

• Davide Mancusi : Chalmers Univ. of Tech., Sweden

1.3. References of PHITS

Please refer the following document in context of using any version of PHITS.

• 20. Sato, Y. Iwamoto, S. Hashimoto, T. Ogawa, T. Furuta, S. Abe, T. Kai, Y. Matsuya, N. Matsuda, Y. Hirata, T. Sekikawa, L. Yao, P.E. Tsai, R.N. Hunter, H. Iwase, Y. Sakaki, K. Sugihara, N. Shigyo, L. Sihver and K. Niita, Recent improvements of the Particle and Heavy Ion Transport code System - PHITS version 3.33, J. Nucl. Sci. Technol. 61, 127-135 (2024). DOI: 10.1080/00223131.2023.2275736. This is an open access article.

Benchmark studies of PHITS are described in the following articles:

• 25. Iwamoto, T. Sato, S. Hashimoto, T. Ogawa, T. Furuta, S. Abe, T. Kai, N. Matsuda, R. Hosoyamada, and K. Niita, Benchmark study of the recent version of the PHITS code, J. Nucl. Sci. Technol. 54:5, 617-635 (2017). DOI: 10.1080/00223131.2017.1297742

• 25. Iwamoto, S. Hashimoto, T. Sato, N. Matsuda, S. Kunieda, Y. Çelik, N. Furutachi and K. Niita, Benchmark study of particle and heavy-ion transport code system using shielding integral benchmark archive and database for accelerator-shielding experiments, J. Nucl. Sci. Technol. 59, 665-675 (2022). DOI: 10.1080/00223131.2021.1993372

Other articles that describe the features of PHITS are:

• 8. Iwase, K. Niita, T.Nakamura, Development of general purpose particle and heavy ion transport Monte Carlo code. J Nucl Sci Technol. 39, 1142-1151 (2002). DOI: 10.1080/18811248.2002.9715305

• 11. Niita, T. Sato, H. Iwase, H. Nose, H. Nakashima and L. Sihver, Particle and Heavy Ion Transport Code System; PHITS, Radiat. Meas. 41, 1080-1090 (2006). DOI: 10.1016/j.radmeas.2006.07.013

• 12. Sihver, D. Mancusi, T. Sato, K. Niita, H. Iwase, Y. Iwamoto, N. Matsuda, H. Nakashima, Y. Sakamoto, Recent developments and benchmarking of the PHITS code, Adv. Space Res. 40, 1320-1331 (2007). DOI: 10.1016/j.asr.2007.02.056

• 12. Sihver, T. Sato, K. Gustafsson, D. Mancusi, H. Iwase, K. Niita, H. Nakashima, Y. Sakamoto, Y. Iwamoto and N. Matsuda, An update about recent developments of the PHITS code, Adv. Space Res. 45, 892-899 (2010). DOI: 10.1016/j.asr.2010.01.002

• 11. Niita, N. Matsuda, Y. Iwamoto, H. Iwase, T. Sato, H. Nakashima, Y. Sakamoto and L. Sihver, PHITS: Particle and Heavy Ion Transport code System, Version 2.23, JAEA-Data/Code 2010-022 (2010).

• 11. Niita, H. Iwase, T. Sato, Y. Iwamoto, N. Matsuda, Y. Sakamoto, H. Nakashima, D. Mancusi and L. Sihver, Recent developments of the PHITS code, Prog. Nucl. Sci. Technol. 1, 1-6 (2011). DOI: 10.15669/pnst.1.1

• 20. Sato, K. Niita, N. Matsuda, S. Hashimoto, Y. Iwamoto, S. Noda, T. Ogawa, H. Iwase, H. Nakashima, T. Fukahori, K. Okumura, T. Kai, S. Chiba, T. Furuta and L. Sihver, Particle and Heavy Ion Transport Code System PHITS, Version 2.52, J. Nucl. Sci. Technol. 50:9, 913-923 (2013). DOI: 10.1080/00223131.2013.814553

• 20. Sato, Y. Iwamoto, S. Hashimoto, T. Ogawa, T. Furuta, S. Abe, T. Kai, P.-E. Tsai, N. Matsuda, H. Iwase, H. Shigyo, L. Sihver, and K. Niita, Features of Particle and Heavy Ion Transport code System (PHITS) version 3.02, J. Nucl. Sci. Technol. 55, 684-690 (2018). DOI: 10.1080/00223131.2017.1419890