Measurements of displacement cross sections of metals for 120-GeV proton beam irradiation

Iwamoto, Yosuke; Matsuda, Hiroki*; Meigo, Shinichiro; Yonehara, Katsuya*; Pellemoine, F.*; Liu, Z.*; Lynch, K.*; Yoshida, Makoto*; Yabuuchi, Atsushi*; Yoshiie, Toshimasa*; et al.

Nuclear Instruments and Methods in Physics Research B, 557, p.165543_1 - 165543_8, 2024/12

https://doi.org/10.1016/j.nimb.2024.165543

The number of displacements per atom is widely used as an indicator of irradiation damage to materials in proton accelerator facilities. Experiments have been carried out on protons below 3 GeV to verify the dpa of metallic materials. However, the dpa for high-energy protons above 3 GeV has not been measured. In order to validate the displacement cross sections of metals in the high-energy region, the electrical resistivity changes of aluminium, copper and tungsten wires at a temperature of 8 K were measured using protons with energy of 120 GeV. The results show that the conventional irradiation damage model of PHITS overestimates the experimental data. On the other hand, the calculation results using the athermal recombination correction model were in agreement with the experimental data.

IAEA Photonuclear Data Library 2019

Kawano, Toshihiko*; Cho, Y. S.*; Dimitriou, P.*; Filipescu, D.*; Iwamoto, Nobuyuki; Plujko, V.*; Tao, X.*; Utsunomiya, Hiroaki*; Varlamov, V.*; Xu, R.*; et al.

Nuclear Data Sheets, 163, p.109 - 162, 2020/01

https://doi.org/10.1016/j.nds.2019.12.002

CIELO collaboration summary results; International evaluations of neutron reactions on uranium, plutonium, iron, oxygen and hydrogen

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.

Nuclear Data Sheets, 148, p.189 - 213, 2018/02

https://doi.org/10.1016/j.nds.2018.02.003

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - U, U, Pu, Fe, O and H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results and outlines plans for the next phase of this collaboration.

Supernova neutrino nucleosynthesis of the radioactive Nb observed in primitive meteorites

Hayakawa, Takehito; Nakamura, Ko*; Kajino, Toshitaka*; Chiba, Satoshi; Iwamoto, Nobuyuki; Cheoun, M. K.*; Mathews, G. J.*

Astrophysical Journal Letters, 779(1), p.L9_1 - L9_5, 2013/12

https://doi.org/10.1088/2041-8205/779/1/L9

Short-lived radioactivities are used as nuclearcosmochronometers for understanding the free decay time from the last nucleosynthesis episode until the time of solar system formation (SSF). Nb (half-life of 34.7 Myr) is one of a short-lived isotope existed at SSF. However, there is a controversy in that the inferred initial abundance ratios for Nb/Nb at the time of SSF cluster around two different values; one is near 10, while the other is near 10. Moreover, the astrophysical mechanism for the synthesis of Nb has remained an unsolved problem. Here we argue that conventional nucleosynthesis mechanisms cannot produce Nb and propose a new mechanism for the nucleosynthesis of this isotopebased upon neutrino induced reactions occurring during core-collapse supernova explosions.

Shielding experiments at high energy accelerators of Fermilab, 3; Neutron spectrum measurements in intense pulsed neutron fields of the 120-GeV proton facility using a current Bonner sphere technique

Hagiwara, Masayuki*; Sanami, Toshiya*; Iwamoto, Yosuke; Arakawa, Hiroyuki*; Shigyo, Nobuhiro*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; Nakamura, Takashi*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.52 - 56, 2011/02

https://doi.org/10.15669/pnst.1.52

In pbar target station, the pulsed proton beam with the power of around 75 kW and the time structure of 1.6 s pulse width and 2.2 s cycle time bombards the pbar production target and produces high instantaneous intensity neutron (burst neutron) fields. The duration of the burst neutrons, which is less than s, is very severe condition to measure neutron spectra with a conventional Bonner sphere technique with pulse readout electronics because of signal pile-up problem. In this study, we have developed a current readout Bonner sphere technique to measure neutron spectra in a burst neutron field. We have measured the neutron spectra on the pbar target and graphite dump. The neutron spectra obtained with the present technique show generally good agreements with the calculation results using MARS code except difference of the thermal neutron flux due to the geometrical problem.

An Update about recent development of the PHITS code

Sihver, L.*; Sato, Tatsuhiko; Gustafsson, K.*; Mancusi, D.*; Iwase, Hiroshi*; Niita, Koji*; Nakashima, Hiroshi; Sakamoto, Yukio; Iwamoto, Yosuke; Matsuda, Norihiro

Advances in Space Research, 45(7), p.892 - 899, 2010/04

https://doi.org/10.1016/j.asr.2010.01.002

We will first present the current status of the General-Purpose Particle and Heavy-Ion Transport code System (PHITS). In particular, we will describe benchmarking of calculated cross sections against measurements; we will introduce a relativistically covariant version of JQMD, called R-JQMD, that features an improved ground-state initialization algorithm, and we will show heavy-ion charge-changing cross sections simulated with R-JQMD and compare them to experimental data and to results predicted by the JQMD model.

Explosive nucleosynthesis in different conditions

Iwamoto, Nobuyuki; Umeda, Hideyuki*; Nomoto, Kenichi*; Tominaga, Nozomu*; Thielemann, F. K.*; Hix, W. R.*

AIP Conference Proceedings 847, p.409 - 411, 2006/07

https://doi.org/10.1063/1.2234441

The observations of metal-poor stars with metallicity [Fe/H] have been extensively performed. The abundance patterns of these stars are well explained by supernova models with extensive material mixing and fallback onto the compact remnant. Nevertheless important deficiencies of odd elements (especially Sc and K) are present in most investigations. Recent simulations of core collapse supernovae showed that innermost ejecta undergo large amounts of neutrino flux and neutrino interactions with materials in these ejecta change electron fraction to . Nucleosynthesis in the proton-rich environments allows Sc and Zn (which are less produced in normal supernova models) to be enriched. Therefore, it is interesting to investigate the influence of a large variation of on explosive nucleosynthesis. We calculate nucleosynthesis with ranging from 0.48 to 0.58 in complete and incomplete Si burning layers in Pop III supernovae. We discuss the production of some important nuclei and compare the abundance patterns with those in observed extremely metal-poor stars.

Prescission and postscission charged particle emissions from the F+Tb reaction

Ikezoe, Hiroshi; Nagame, Yuichiro; ; Sugiyama, Yasuharu; Tomita, Yoshiaki; Ideno, K.; Hamada, S.; ; Iwamoto, Akira;

Physical Review C, 49(2), p.968 - 976, 1994/02

https://doi.org/10.1103/PhysRevC.49.968

no abstracts in English

Charged particle emissions in fission process

Ikezoe, Hiroshi; Shikazono, Naomoto; Nagame, Yuichiro; Otsuki, Tsutomu*; Sugiyama, Yasuharu; Tomita, Yoshiaki; Ideno, K.; Kanno, Ikuo; H.J.Kim*; B.J.Qi*; et al.

Nuclear Physics A, 538, p.299C - 306C, 1992/00

no abstracts in English

Pre-scission He multiplicity in the F + Au reaction

Ikezoe, Hiroshi; Shikazono, Naomoto; Nagame, Yuichiro; Sugiyama, Yasuharu; Tomita, Yoshiaki; Ideno, K.; Iwamoto, Akira;

Physical Review C, 42(1), p.342 - 353, 1990/07

https://doi.org/10.1103/PhysRevC.42.342

no abstracts in English