SiC sensor wire test by heavy ion beam irradiation, 2

Meigo, Shinichiro; Yamaguchi, Yuji

Proceedings of 21st Annual Meeting of Particle Accelerator Society of Japan (Internet), p.853 - 858, 2024/10

https://www.pasj.jp/web_publish/pasj2024/proceedings/PDF/FRP0/FRP006.pdf

no abstracts in English

Production cross-sections of residual nuclides from Zr + at 27 MeV/nucleon

Hwang, J.*; Chillery, T.*; Dozono, Masanori*; Imai, Nobuaki*; Michimasa, Shinichiro*; Sumikama, Toshiyuki*; Chiga, Nobuyuki*; Ota, Shinsuke*; Nakayama, Shinsuke; 49 of others*

Progress of Theoretical and Experimental Physics (Internet), 2024(9), p.093D03_1 - 093D03_12, 2024/09

https://doi.org/10.1093/ptep/ptae139

Nuclear transmutation emerges as a promising approach for reprocessing high-level waste, specifically treating long-lived nuclides like Zr from spent fuel. It is essential to accumulate reaction data for these nuclei to advance this prominent treatment and to build a comprehensive understanding of reaction mechanisms. In this study, the residual production cross-sections resulting from proton-induced reactions on Zr were measured at 27 MeV/nucleon in inverse kinematics. At the RIKEN-RIBF facility the OEDO beamline was used to deduce production cross-sections for isotopes, Nb, Zr, and Y. Comparing the results from this study and prior research with calculated excitation functions, a moderate agreement is found with theoretical predictions derived from TALYS and CCONE. Despite the potential limitations of low-energy proton-induced reactions for Zr transmutation, the measured cross-sections offer valuable insights for future considerations in nuclear-waste treatment facilities. This is particularly relevant for facilities exploring innovative methods, such as accelerator-driven systems.

Conceptual study of Post Irradiation Examination (PIE) Facility at J-PARC

Saito, Shigeru; Meigo, Shinichiro; Makimura, Shunsuke*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Maekawa, Fujio

JAEA-Technology 2023-025, 48 Pages, 2024/03

JAEA-Technology-2023-025.pdf:3.11MB

JAEA has been developing Accelerator-Driven Systems (ADS) for research and development of nuclear transmutation using accelerators in order to reduce the volume and hazardousness of high-level radioactive waste generated by nuclear power plants. In order to prepare the material irradiation database necessary for the design of ADS and to study the irradiation effects in Lead-Bismuth Eutectic (LBE) alloys, a proton irradiation facility is under consideration at J-PARC. In this proton irradiation facility, 250 kW proton beams will be injected into the LBE spallation target, and irradiation tests under LBE flow will be performed for candidate structural materials for ADS. Furthermore, semiconductor soft-error tests, medical RI production, and proton beam applications will be performed. Among these, Post Irradiation Examination (PIE) of irradiated samples and RI separation and purification will be carried out in the PIE facility to be constructed near the proton irradiation facility. In this PIE facility, PIE of the equipment and samples irradiated in other facilities in J-PARC will also be performed. This report describes the conceptual study of the PIE facility, including the items to be tested, the test flow, the facilities, the test equipment, etc., and the proposed layout of the facility.

Studying the impact of deuteron non-elastic breakup on Zr + d reaction cross sections measured at 28 MeV/nucleon

Chillery, T.*; Hwang, J.*; Dozono, Masanori*; Imai, Nobuaki*; Michimasa, Shinichiro*; Sumikama, Toshiyuki*; Chiga, Nobuyuki*; Ota, Shinsuke*; Nakayama, Shinsuke; 49 of others*

Progress of Theoretical and Experimental Physics (Internet), 2023(12), p.121D01_1 - 121D01_11, 2023/12

https://doi.org/10.1093/ptep/ptad139

The deuteron is a loosely bound system which can easily break up into its constituent proton and neutron whilst in the presence of Coulomb and nuclear fields. Previous experimental studies have shown that this breakup process has a significant impact on residual nucleus production from deuteron bombardment in the high energy range of 50 - 210 MeV/nucleon. However, there remains a lack of cross-section data at energies below 50 MeV/nucleon. The current study determined Zr + d reaction cross sections under inverse kinematics at approximately 28 MeV/nucleon using the BigRIPS separator, OEDO beamline, and SHARAQ spectrometer. Cross sections from this research were compared with previous measurements and theoretical calculations. The experimental results show a large enhancement of the production cross sections of residual nuclei, especially those produced from a small number of particle emissions, compared to the proton-induced reaction data at similar bombarding energy. The DEURACS calculation, which quantitatively takes deuteron-breakup effects into account, reproduces the data well. As a long-lived fission product, Zr remains a challenge for nuclear waste disposal and treatment. This study's low-energy data may assist future consideration of nuclear-waste treatment facilities, where Zr + d may feasibly transmute the waste into short-lived/stable nuclei.

Development of new data acquisition system for several beam monitors in J-PARC RCS

Yoshimoto, Masahiro; Takahashi, Hiroki; Harada, Hiroyuki; Chimura, Motoki; Fuwa, Yasuhiro; Hayashi, Naoki; Kuriyama, Yasutoshi*; Sawabe, Yuki*; Hatakeyama, Shuichiro*

Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.839 - 843, 2023/11

https://www.pasj.jp/web_publish/pasj2023/proceedings/PDF/FRP0/FRP08.pdf

In the J -PARC 3GeV synchrotron accelerator (RCS), a new signal processing system for beam monitors is been developing to replace the existing system for the main beam monitors that monitor the stability of the accelerator: beam loss monitor, beam position monitor and beam current monitor. The new system will consist of a TAG server and an ADC module that can be used commonly for the three main monitors. The main design concepts of the new system are: (1) the TAG server divides various beam J-PARC tag information to each ADC module, (2) the ADC module converts acquisition data from beam monitors to digital signals by ADC and performs high-speed analysis by FPGA with switching analysis methods to suit each monitor, (3) the ADC module periodically outputs the analysis data with tag information by packing the signal processing data of all shots for about 10 seconds, and also outputs any one shot data on-demand, and (4) the raw waveform data, the latest four shots of FFT-related data in the process of analysis and bunch data for each cycle are stored in the internal memory of the ADC module, and the data can be read out as needed. In this presentation, we will report on the progress of the data acquisition test of tag information reading and beam monitor signals using the prototype under development.

Development of a single-ended magnetic alloy loaded cavity in the Japan Proton Accelerator Research Complex rapid cycling synchrotron

Yamamoto, Masanobu; Nomura, Masahiro; Okita, Hidefumi; Shimada, Taihei; Tamura, Fumihiko; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Sugiyama, Yasuyuki*; Yoshii, Masahito*

Progress of Theoretical and Experimental Physics (Internet), 2023(7), p.073G01_1 - 073G01_16, 2023/07

https://doi.org/10.1093/ptep/ptad085

The Japan Proton Accelerator Research Complex (J-PARC) Rapid Cycling Synchrotron (RCS) employs Magnetic Alloy (MA) loaded cavities. We realize multi-harmonic rf driving and beam loading compensation owing to the broadband characteristics of the MA. The currently installed cavity is the conventional type one which is designed to be driven by tube amplifiers in a push-pull operation. The push-pull operation has some advantages, i.e., suppressing a higher harmonic distortion without the beam acceleration and shortening the cavity length. However, a disadvantage arises at the high intensity beam acceleration where the multi-harmonic rf driving causes a severe imbalance of the anode voltage swing and restricts the tube operation. Although we have achieved an acceleration for the design beam power of 1 MW, the imbalance becomes an issue to further increase the beam power. We have developed a single-ended MA cavity to avoid such difficulty. The cavity has no tube imbalance intrinsically and it is found that the power consumption to drive the cavity can be reduced compared with the conventional one.

Development of secondary GeV protons utilization using scattering at beam window

Meigo, Shinichiro; Yamaguchi, Yuji; Nakano, Keita*; Sugihara, Kenta*

Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.132 - 136, 2023/01

https://www.pasj.jp/web_publish/pasj2022/proceedings/PDF/THOB/THOB01.pdf

J-PARC accelerator facility is the only accelerator facility in Japan that can provide proton beams in the energy range of 400 MeV or higher. In the J-PARC accelerator facility, it is difficult to install users' experimental equipment inside the proton beam duct in order to maintain stable user operation. In addition, due to the characteristics of the synchrotron accelerator, it is not possible to supply a low-intensity beam enough to confirm the detector. In addition, it is important to improve the intranuclear cascade model (INCL) for high-intensity proton accelerator facilities such as accelerator-driven transmutation systems (ADS), etc. In order to improve the INCL, DDX of the forward-most emitted particles is important, but new data should be obtained since there are few experimental data available. In order to promote space utilization and to improve the accuracy of the INCL, energy spectra of scattered protons at the Al beam window placed at the inlet of the 3NBT dump were measured. In the experiment, plastic scintillators were used with 400 MeV proton beam. The results show that the spectra have sharp peaks due to elastic scattering. The calculation of the PHITS code using INCL reproduced the sharp peak due to elastic scattering well, although it overestimated the contribution of quasi-elastic scattering in the experimental data. In conclusion, it is clear that the present method can be used to utilize protons in several GeV regions for space exploration.

Paper award of Atomic Energy Society of Japan in 2021; JENDL/DEU-2020: deuteron nuclear data library for design studies of accelerator-based neutron sources

Nakayama, Shinsuke

Kaku Deta Nyusu (Internet), (133), p.88 - 99, 2022/10

http://www.aesj.or.jp/~ndd/ndnews/No133.html

The content of the paper that received the Paper Award of Atomic Energy Society of Japan in 2021 is outlined. Although the use of deuteron accelerator-based neutron sources has been proposed in various fields, deuteron nuclear database accurate enough to be applied to the design study of such neutron sources had not been developed. Under these situations, we had developed a deuteron nuclear database, JENDL/DEU-2020. It contains evaluated deuteron nuclear data for light nuclei (Li, Be, C), which are candidates for deuteron beam irradiation targets of the neutron sources. Evaluation of JENDL/DEU-2020 was performed by using the code system DEURACS with further modifications. In order to validate the accuracy of the database, simulations using the particle transport code were performed under various conditions with different target nuclides and incident deuteron energies, and the results were compared with the available experimental data. As a result, it was found that JENDL/DEU-2020 significantly improves the prediction accuracy of experimental data under a wider range of conditions than other nuclear reaction databases or the nuclear reaction models implemented in transport calculation codes.

Beam emittance growth due to the strong space-charge field at low energy of a high-intensity ion linac and its mitigation using an octupole magnetic field

Chimura, Motoki; Harada, Hiroyuki; Kinsho, Michikazu

Progress of Theoretical and Experimental Physics (Internet), 2022(6), p.063G01_1 - 063G01_26, 2022/06

https://doi.org/10.1093/ptep/ptac077

In the low-energy region of a high-intensity ion linac, a strong space-charge field causes a rapid beam emittance growth over a short distance of only few meters. The beam emittance growth leads to a beam loss and the machine activation raising a serious issue for regular maintenance of the accelerator component and beam power ramp up. In this work, we studied the mechanism of beam emittance growth due to the space-charge field based on three-dimensional particle-tracking simulation and theoretical considerations. Numerical simulations done for the high-intensity linac at J-PARC shows that the nonlinear terms in the space-charge field directly cause a beam emittance growth and beam halo formation. Then, we also propose a method to mitigate the beam emittance growth by using an octupole magnetic field, which arises as one of the nonlinear terms in the space-charge field. By applying this method in the simulation, we have succeeded mitigating the beam emittance growth.

Theoretical study of deuteron-induced reactions in the nuclear data field

Nakayama, Shinsuke; Iwamoto, Osamu; Watanabe, Yukinobu*; Ogata, Kazuyuki*

Few-Body Systems, 63(1), p.4_1 - 4_6, 2022/03

https://doi.org/10.1007/s00601-021-01712-2

Intensive neutron sources using deuteron accelerators have been proposed for not only science and engineering fields but also medical applications. For the engineering design of such facilities, accurate and comprehensive nuclear data of deuteron-induced reactions are indispensable. However, it is difficult to meet the requirement by employing experimental data alone. Thus, theoretical model calculations play a key role in completing the necessary nuclear data by interpolation and extrapolation of experimental data. Under the above situations, we have been developing a code system dedicated for deuteron-induced reactions, called DEURACS. In the present work, calculations using DEURACS are compared with available experimental data and validation of the present modelling in DEURACS is discussed. Moreover, the importance of consideration of the breakup processes for accurate prediction of deuteron-induced reactions is also presented.