Nobuhiro Shigyo

Nuclear Data Evaluations for JENDL High‐Energy File

An overview is presented of recent nuclear data evaluations performed for the JENDL high‐energy (JENDL‐HE) file, in which neutron and proton cross sections for energies up to 3 GeV are included for the whole 132 nuclides. The current version of the JENDL‐HE file consists of neutron total cross sections, nucleon elastic scattering cross sections and angular distributions, nonelastic cross sections, production cross sections and double‐differential cross sections of secondary light particles (n, p, d, t, 3He, α, and π) and gamma‐rays, isotope production cross sections, and fission cross sections in the ENDF6 format. The present evaluations are performed on the basis of experimental data and theoretical model calculations. For the cross section calculations, we have constructed a hybrid calculation code system with some available nuclear model codes and systematics‐based codes, such as ECIS96, OPTMAN, GNASH, JQMD, JAM, TOTELA, FISCAL, and so on. The evaluated cross sections are compared with available experimental data and the other evaluations. Future plans of our JENDL‐HE project are discussed along with prospective needs for high‐energy cross section data.An overview is presented of recent nuclear data evaluations performed for the JENDL high‐energy (JENDL‐HE) file, in which neutron and proton cross sections for energies up to 3 GeV are included for the whole 132 nuclides. The current version of the JENDL‐HE file consists of neutron total cross sections, nucleon elastic scattering cross sections and angular distributions, nonelastic cross sections, production cross sections and double‐differential cross sections of secondary light particles (n, p, d, t, 3He, α, and π) and gamma‐rays, isotope production cross sections, and fission cross sections in the ENDF6 format. The present evaluations are performed on the basis of experimental data and theoretical model calculations. For the cross section calculations, we have constructed a hybrid calculation code system with some available nuclear model codes and systematics‐based codes, such as ECIS96, OPTMAN, GNASH, JQMD, JAM, TOTELA, FISCAL, and so on. The evaluated cross sections are compared with available experi...

Development of SCINFUL-QMD Code to Calculate the Neutron Detection Efficiencies for Liquid Organic Scintillator up to 3 GeV

The Monte Carlo code, designeted SCINFUL-QMD, has been developed to calculate neutron detection efficiency up to 3 GeV for liquid organic scintillators such as NE-213. The existing Monte Carlo code, SCINFUL, is known to reproduce a response function and detection efficiency at incident neutron energies below 80 MeV. We incorporate the quantum molecular dynamics plus statistical decay model (QMD+SDM) into SCINFUL to extend the upper limit of incident neutron energy to 3 GeV. The results by SCINFUL-QMD are compared with experimental data and those of CECIL. The SCINFUL-QMD exhibits an increase in detection efficiency above 300 MeV. This tendency agrees with one of the experimental data. The increase is achived by taking charged pion production into account.

Features of Particle and Heavy Ion Transport code System (PHITS) version 3.02

ABSTRACT We have upgraded many features of the Particle and Heavy Ion Transport code System (PHITS) and released the new version as PHITS3.02. The accuracy and the applicable energy ranges of the code were greatly improved and extended, respectively, owing to the revisions to the nuclear reaction models and the incorporation of new atomic interaction models. Both condense history and track-structure methods were implemented to handle the electron and positron transport, although the latter is reliable only for simulations in liquid water. In addition, several user-supportive functions were developed, such as new tallies to efficiently obtain statistically better results, radioisotope source-generation function, and software tools useful for applying PHITS to medical physics. Owing to the continuous improvement and promotion of the code, the number of registered users has exceeded 3,000, and it is being used in diverse areas of study, including accelerator design, radiation shielding and protection, medical physics, and cosmic-ray research. In this paper, we summarize the basic features of PHITS3.02, especially those of the physics models and the functions implemented after the release of PHITS2.52 in 2013.

Experimental studies of shielding and irradiation effects at high-energy accelerator facilities

Abstract Experimental studies of shielding and radiation effects are carried out at Fermi National Accelerator Laboratory (FNAL) under collaboration between FNAL and Japan, aiming at benchmarking simulation codes and studying irradiation effects for the upgrade and design of new high-energy accelerator facilities. The purposes of this collaboration are (a) acquisition of shielding data in a proton beam energy region above 100 GeV, (b) further evaluation of predictive accuracy of the PHITS and MARS codes, (c) modification of physics models and data in these codes if needed, (d) characterization of radiation fields for studies of radiation effects, and (e) development of a code module for an improved description of radiation effects. The first campaign of the experiment was carried out at the Pbar target station and NuMI experimental station at FNAL, which use irradiation of targets with 120-GeV protons for antiproton and neutrino production, respectively. The generated secondary particles passing through steel, concrete, and rock were measured by activation methods as well as by other detectors such as a scintillator with a veto counter, phoswich detector, and a Bonner ball counter on trial. Preliminary experimental and calculated results are presented.

Study on effective average (γ, n) Cross Section for 89Y, 90Zr, 93Nb, and 133Cs and (γ, 3n) cross section for 99Tc

A nondestructive detection technique was proposed for the easy assessment of long-lived radionuclides by the use of bremsstrahlung photons. The nuclide of 99Tc was considered for the assessment over an effective average 99Tc (γ, 3n) 96Tc cross section. For validating the experimental method on 99Tc, photonuclear (γ, n) cross sections of 89Y, 90Zr, 93Nb, and 133Cs were measured. Continuous-energy bremsstralung photons were generated from a platinum target bombarded by an electron beam of 32/36MeV from an electron linac. The photonuclear (γ, n) cross sections were previously measured by Saclay (France) and Livermore (USA) laboratories for 89Y, 90Zr, 93Nb, and 133Cs nuclides. For 89Y, 90Zr, and 133Cs, the present results were in good agreement, within 9% deviation with Saclay and an acceptable deviation of 14–36% from Livermore. In the case of 93Nb, the contribution for 93Nb (γ, n) 92Nb* in the metastable state was 55.2% of the total (γ, n) cross section of Saclay in an averaged form. The present experimental method was thus confirmed to show a good accuracy. The effective average cross section of 99Tc (γ, 3n) 96Tc was obtained as 2.30 mb in the energy range of 25.723–36 MeV.

Parameterization of Proton-induced Neutron Production Double Differential Cross Section up to 3 GeV in Terms of Moving Source Model

The parameterization of double differential cross sections is made for the neutron emission from proton- induced spallation reaction. The emitted neutron data for incident proton energies of 0.8 to 3 GeV are analyzed by the three-component moving source model based on the Maxwell-like energy distribution. In addition, a Gaussian-shaped term is utilized for reproducing the neutron spectrum originating from the quasi-elastic- and quasi-inelastic-like scattering. The systematics of parameters is obtained in the target mass number region from C to Pb.

Measurements of Neutron Spectra Produced from a Thick Tungsten Target Bombarded with 0.5- and 1.5-GeV Protons

For validation of calculation codes that are employed in the design of pulse spallation neutron source and accelerator driven system, spectrum of neutrons produced from a thick target plays an important role. However, appropriate experimental data were scarce for the incident energies higher than 0.8 GeV. In this study, the spectrum from a thick tungsten target was measured The experiment was carried out at the π2 beam line of the 12-GeV proton synchrotron at KEK. The tungsten target was bombarded by the 0.5- and 1.5-GeV secondary protons. Spectrum of neutrons was measured by the time-of-flight technique using organic scintillators of NE213, The calculated result with NMTC/JAM and MCNP-4A is compared with the measured data. It is found that the NMTC/JAM generally gives a good agreement with experiment. The NMTC/JAM, however, gives 50 % lower neutron flux in the energy region 20~80 MeV, which is consistent with the results in previous comparison of lead target. For the neutrons between 20 and 80 MeV, the calculation using with the in-medium nucleon-nucleon cross sections reproduced the experiment fairly well.

Measurement of Neutron-Production Double-Differential Cross Sections for Intermediate Energy Pion Incident Reaction

Neutron-production double-differential cross sections for 870-MeV π+ and π− and 2.1-GeV π+ mesons incident on iron and lead targets were measured with NE213 liquid scintillators by time-of-flight technique. NE213 liquid scintillators 12.7 cm in diameter and 12.7 cm thick were placed in directions of 15, 30, 60, 90, 120 and 150°. The typical flight path length was 1.5 m. Neutron detection efficiencies were derived from the calculation results of SCINFUL and CECIL codes. The experimental results were compared with the JAM code. The double differential cross sections calculated by the JAM code disagree with experimental data at neutron energies below about 30 MeV. JAM overestimates π+-incident neutron-production cross sections in forward angles at neutron energies of 100 to 500 MeV.

Parameterization of Fragmentation Cross Section for Proton-Induced Spallation Reaction

The authors study the systematics of the fragmentation reaction for incident proton energies up to 3GeV. The mass yields of the reaction are successfully described by the liquid-gas phase transition model assuming reasonable values of the nuclear temperature. For representing the kinetic energy spectra, a double integral formula considering the effects of the Coulomb barrier and the fragment excitation energy is confirmed to be usable. Another formula with a simpler form is introduced for reproducing the energy spectra. A formula utilizes five adjustable parameters, and the authors construct empirical expressions to determine them. The nuclear temperature common to both kinetic energy spectra and mass yields of the fragments is found to be useful for describing the fragmentation phenomena. The present systematics are suited for being incorporated as a subroutine set into the High Energy Transport Code.

Nuclear Data Evaluations on Zirconium, Niobium and Tungsten for Neutron and Proton Incidence up to 200 MeV

Nuclear data were evaluated on 90 91 92 94 96Zr, 93Nb and 182 183 184 186W for neutron and proton incidence up to 200 MeV. Optical model potential parameters were searched to give good agreements with experimental values of elastic-scattering, total, and total-reaction cross sections. The GNASH pre-equilibrium/statistical model code was used for evaluations of particle-production cross sections. Since the direct inelastic-scatterings induced by the excitations of giant resonances are not negligible for these nuclei, the calculation was performed to take them into consideration. For composite-particle emission cross sections from pre-equilibrium states, semi-empirical methods were utilized to give good agreements with experimental results. We also calculated isotope-production cross sections. Evaluated cross sections were compared with values by measurements and the LA150 evaluations.