NEA-1857 PHITS-2.88.

PHITS-2.88

PHITS can deal with the transport of almost all particles (nucleons, nuclei, mesons, photons, and electrons) over wide energy ranges, using several nuclear reaction models and nuclear data libraries (Iwase et al 2002, Niita et al 2006, Sihver et al 2010, Niita et al 2010, and Sato et al 2013). Geometrical configuration of the simulation can be set with GG (General Geometry). Various quantities such as heat deposition, track length and production yields can be deduced from the simulation, using implemented estimator functions called "tally". The code also has a function to draw 2D and 3D figures of the calculated results as well as the setup geometries, using a code ANGEL.

The physical processes included in PHITS can be divided into two categories, transport process and collision process. In the transport process, PHITS can simulate motion of particles under external fields such as magnetic and gravity. Without the external fields, neutral particles move along a straight trajectory with constant energy up to the next collision point. However, charge particles interact many times with electrons in the material losing energy and changing direction. PHITS treats ionization processes not as collision but as a transport process, using the continuous-slowing-down approximation. The average stopping power is given by the charge density of the material and the momentum of the particle taking into account the fluctuations of the energy loss and the angular deviation.

In the collision process, PHITS can simulate the elastic and inelastic interactions as well as decay of particles. The total reaction cross section, or the life time of the particle is an essential quantity in the determination of the mean free path of the transport particle. According to the mean free path, PHITS chooses the next collision point using the Monte Carlo method. To generate the secondary particles of the collision, we need the information of the final states of the collision. For neutron induced reactions in low energy region, PHITS employs the cross sections from evaluated nuclear data libraries JENDL-4.0 (Shibata et al 2011). For high energy neutrons and other particles, we have incorporated several models such as JAM (Nara et al 1999), INCL (Cugnon et al 2011), INCL-ELF (Sawada et al 2012) and JQMD (Niita et al 1995) to simulate nuclear reactions up to 100 GeV/u.

The special features of PHITS are the event generator mode (Iwamoto et al 2007) and the microdosimetric function (Sato et al 2009). Owing to the event generator mode, PHITS can determine the profiles of all secondary particles generated from a single nuclear interaction even using nuclear data libraries, taking the momentum and energy conservations into account. The microdosimetric function gives the probability densities of deposition energy in microscopic sites such as lineal energy y and specific energy z, using the mathematical model developed based on the results of the track structure simulation. These features are very important for various purposes such as the estimations of soft-error rates of semi-conductor devices induced by neutrons, and relative biological effectiveness of charged particles.

From version 2.64, Prompt gamma spectrum and isomer production rates can be precisely estimated, owing to the implementation of EBITEM (ENSDF-Based Isomeric Transition and isomEr production Model). The photo-nuclear reaction model was improved up to 140 MeV.

From version 2.76, electron and photon transport algorithm based on EGS5 (Hirayama et al. 2005) was incorporated. Models for describing photo-nuclear reaction above 140 MeV and muon-nuclear reaction were implemented. Event-generator mode version 2 was developed. Relativistic theory can be considered in the JQMD model.

From version 2.82, the function to read tetrahedral geometry (a kind of polygonal geometry) was implemented. Model for describing nuclear resonance florescence (NRF) was implemented. Point estimator tally (t-point) was developed.

From version 2.88, the functions to output the tally results in xyz-mesh in the input format of ParaView has been implemented. The RI source generation function and weight window generator have also been implemented.

The Monte Carlo method is used.

PHITS cannot be used for microscopic track-structure simulation, since PHITS adopts the continuous- slowing-down approximation for the ionization process of charged particle.

24 sec / 2,000 particles for "recommendation/shielding/shielding.inp"
21 sec / 2,000 particles for " recommendation/photontherapy/photontherapy.inp "
on Windows Vista, Intel Core2 Quad Q9550@ 2.83GHz, 4.0GB RAM system.

The distribution package includes:

• ANGEL: graphic software to draw 2D and 3D figures of the calculated results as well as the setup geometries.

• Cross section data libraries: Neutron nuclear data library and photo- and electro-atomic data libraries evaluated mainly based on Japanese Evaluated Nuclear Data Library version 4 (JENDL-4.0).

• DCHAIN-SP: Program for calculating the time dependence of activation during and after irradiations

• H. Hirayama, Y. Namito, A.F. Bielajew, S.J. Wilderman and W.R. Nelson: “The EGS5 Code System” SLAC-R-730 (2005) and KEK Report 2005-8 (2005)

• Y. Iwamoto, K. Niita, Y. Sakamoto, T. Sato and N. Matsuda: "Validation of the event generator mode in the PHITS code and its application" International Conference on Nuclear Data for Science and Technology 2007, DOI: 10.1051/ndata:07417 (2007)

• H. Iwase, K. Niita, T. Nakamura: "Development of general-purpose particle and heavy ion transport Monte Carlo code", J. Nucl. Sci. and Technol. 39, 1142 (2002).

• Y. Nara, N. Otuka, A. Ohnishi, K. Niita, S. Chiba: "Relativistic nuclear collisions at 10A GeV energies from p+Be to Au+Au with the hadronic cascade model", Phys. Rev. C61, 024901 (1999).

• J. Cugnon, A. Boudard, S. Leray, and D. Mancusi: "New Features of the INCL4 Model for Spallation Reactions", J. Korean Phys. Soc. 59, 955-958 (2011).

• Y. Sawada, Y. Uozumi, S. Nogamine, T. Yamada, Y. Iwamoto, T. Sato and K. Niita: "Intranuclear cascade with emission of light fragment code implemented in the transport code system PHITS", Nucl. Instr. Meth. B 291, 38-44 (2012).

• K. Niita, T. Sato, H. Iwase, H. Nose, H. Nakashima, L. Sihver: "PHITS- a particle and heavy ion transport code system", Radiation Measurements 41, 1080 (2006).

• K. Niita, S. Chiba, T. Maruyama, H. Takada, T. Fukahori, Y. Nakahara and A. Iwamoto: "Analysis of the (N,Xn') reactions by quantum molecular dynamics plus statistical decay model", Phys. Rev. C 52, 2620 (1995)

• T. Sato, Y. Kase, R. Watanabe, K. Niita and L. Sihver: "Biological dose estimation for charged-particle therapy using an improved PHITS code coupled with a microdosimetric kinetic model", Radiat. Res. 171, 107-117 (2009)

• T. 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, 913-923 (2013)

• L. 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).

• K. Shibata, O. Iwamoto, T. Nakagawa, N. Iwamoto, A. Ichihara, S. Kunieda, S. Chiba, K. Furutaka, N. Otuka, T. Ohsawa, H. Matsunobu, A. Zukeran, S. Kamada and J. Katakura: "JENDL-4.0: A New Library for Nuclear Science and Engineering", J. Nucl. Sci. Technol. 48, 1-30 (2011).

• System memory: 1 GB or larger (more than 2 GB is recommended)

• Hard disk: 6 GB or larger

• OS: Windows (XP or higher), Mac (OS X v10.5 or higher), Linux or Unix

• Editor that can show the line number

• EPS viewer such as Ghostscript and Gsview

• Recommended Fortran compiler (optional): Intel Fortran 11.1 (or later) and gfortran 4.7 or 4.8.

Koji Niita

Research Organization for Information Science and Technology, Tokai, Ibaraki, Japan

Norihiro Matsuda, Shintaro Hashimoto, Yosuke Iwamoto, Tatsuhiko Sato, Takuya Furuta, Tatsuhiko Ogawa, Shinichiro Abe, Hiroshi Nakashima, Tokio Fukahori, Keisuke Okumura and Tetsuya Kai

Japan Atomic Energy Agency, Tokai, Ibaraki, Japan

Hiroshi Iwase

High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan

Satoshi Chiba

Tokyo Institute of Technology, Tokyo, Japan

Lembit Sihver

Technische Universität Wien, Austria