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Journal Articles

Progress status in fabrication of HBC stripper foil for 3-GeV RCS at J-PARC in Tokai site

Yoshimoto, Masahiro; Yamazaki, Yoshio; Nakanoya, Takamitsu; Saha, P. K.; Kinsho, Michikazu

EPJ Web of Conferences (Internet), 229, p.01001_1 - 01001_7, 2020/02

In the 3-GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), we adopted thick Hybrid type Boron-doped Carbon (HBC) stripper foil for the multi-turn H$$^{-}$$ charge-exchange injection. The HBC stripper foil developed at KEK has been successfully demonstrated to improve the foil lifetime significantly. Early manufacturing process of the stripper foil in the J-PARC had been carried out in following two steps: foil fabrication in KEK Tsukuba-site and foil preparation in JAEA Tokai-site. However, to proceed with the foil manufacturing in a same place efficiently, the carbon discharge arc-evaporation system for HBC stripper foil was removed from the Tsukuba-site and relocated in the Tokai-site. After reassembling of the carbon discharge arc-evaporation system, performance evaluation tests of new HBC foil which are produced at the JAEA Tokai site (J-HBC) are implemented at the TIARA facility of QST-Takasaki. As results of argon beam irradiation for lifetime evaluation, components analysis with RBS method, and impurity evaluation with micro-PIXE method, we can verify that the J-HBC foil performs pretty much equally to the original HBC foil. After the irradiation test by using 400MeV H$$^{-}$$ beam in the J-PARC RCS, user operation by using the J-HBC foil was successfully demonstrated for 10 days.

Journal Articles

Current Status of R&D and PIE Program for ADS Material Development in JAEA

Saito, Shigeru; Okubo, Nariaki; Obayashi, Hironari; Wan, T.; Sugawara, Takanori; Sasa, Toshinobu; Maekawa, Fujio

JPS Conference Proceedings (Internet), 28, p.071003_1 - 071003_6, 2020/02

Japan Atomic Energy Agency (JAEA) proposes transmutation of minor actinides (MA) by accelerator-driven systems (ADS). The ADS designed by JAEA is a system composed by LBE (Lead-Bismuth Eutectic) spallation target and a subcritical core. In the ADS, a beam window (BW) is exposed in complex field of heavy irradiation by proton/neutron and corrosion by flowing LBE. To develop ADS structural materials, it is of critical importance to investigate materials used in such environment. Thus, JAEA plans to construct a proton irradiation facility at the J-PARC to prepare an irradiation database for candidate ADS structural materials and to investigate irradiation effects in flowing LBE environment. In this paper, giving a whole scope of the JAEA ADS development, some results of experimental measurements and the specific program for planed R&D will be presented.

Journal Articles

Consistent description of light composite particle emission in deuteron-induced reactions

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

Physical Review C, 100(4), p.044603_1 - 044603_8, 2019/10

 Times Cited Count:0 Percentile:100(Physics, Nuclear)

The weakly-bound nature of the deuteron brings the complexity of deuteron-induced reactions compared to nucleon-induced ones, and is expected to affect various physical quantities observed in deuteron-induced reactions. Aiming to deep understanding and accurate prediction for the emission of light composite particle (LCP) in deuteron-induced reactions, we revise the computational system dedicated to deuteron-induced reactions, called DEURACS. The model by Iwamoto and Harada describing pre-equilibrium cluster emission which was successfully applied to LCP emission innucleon-induced reactions is integrated into the framework of DEURACS, in which the breakup processes of incident deuteron are explicitly taken into account. The phenomenological model by Kalbach is also adopted to estimate the contribution from the direct pickup process. Using the revised DEURACS, we analyze the $$(d,xt)$$, $$(d,xmathrm{^{3}He})$$, and $$(d,xalpha)$$ reactions in the target mass range $$27 leqslant A leqslant 90$$. Regardless of the targets, the calculation results successfully reproduced the experimental data for each reaction, simultaneously. These results demonstrates that the LCP emission from the pre-equilibrium and compound nucleus processes in deuteron-induced reactions,which occupies a large part of the total LCP emission,can be described by the same theoretical models as used in nucleon-induced reactions when the breakup processes of incident deuteron are properly considered.

Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:3 Percentile:25.77(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Recent progress of the J-PARC RCS beam commissioning and operation; Efforts to realize a higher beam power beyond 1 MW

Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; et al.

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.574 - 578, 2019/07

no abstracts in English

Journal Articles

Study of heavy ion acceleration in J-PARC

Harada, Hiroyuki; Saha, P. K.; Kinsho, Michikazu

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.179 - 182, 2019/07

Recently, humankind had big discovery about neutron star, which is great big nuclear in the space. They are discovery of neutron star with twice mass of solar in 2010 and observation of gravity wave when two neutron start incorporate in 2017. In order to understand the high dense matter like the neutron star, project of experimental researches by using accelerated heavy ion beams become heated in the world, such RHIC-BES-II program, FAIR project, NICA project, etc. The J-PARC provides MW class high intensity proton beams to many experiments and researches. We have study of the heavy ion beam in J-PARC to fully utilize high intensity ability of J-PARC. We propose the accelerator scheme of the beam in J-PARC and the intensity will reach to the world record. In our talk, we will report the current status of proton beam and the accelerator scheme for the high-intensity heavy ion beam in J-PARC.

Journal Articles

Evaluation of beam-loss suppression method by nonlinear space charge force in a high intensity linac

Chimura, Motoki*; Harada, Hiroyuki; Moriya, Katsuhiro; Okabe, Kota; Kinsho, Michikazu

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.728 - 732, 2019/07

The increase of space charge effect in high intensity beam causes the increase of the beam-loss. Beam loss limits beam intensity for accelerator equipment activation. Therefore, it is important to suppress the emittance growth due to the space charge effect. I focused on the low energy region in the linac where the space charge effect becomes remarkable. In order to identify the origin of the emittance growth due to the effect, a simulation was performed with a 3-D particle-in-cell simulation code, and evaluated the influence of the effects in the J-PARC medium energy beam transport line (MEBT1) entrance to DTL exit. As a result, it was confirmed that distortion of phase space distribution occurred due to nonlinear space charge force and that leading to emittance growth. I proposed to suppress the emittance growth by using an octupole magnet that gives nonlinear force to the beam. We report the new method and simulation results.

Journal Articles

Progress of long-time operation and industrial use of negative ion source for particle accelerator

Oguri, Hidetomo

Purazuma, Kaku Yugo Gakkai-Shi, 95(7), p.340 - 344, 2019/07

no abstracts in English

Journal Articles

Shape coexistence in $$^{178}$$Hg

M$"u$ller-Gatermann, C.*; Dewald, A.*; Fransen, C.*; Auranen, K.*; Badran, H.*; Beckers, M.*; Blazhev, A.*; Braunroth, T.*; Cullen, D. M.*; Fruet, G.*; et al.

Physical Review C, 99(5), p.054325_1 - 054325_7, 2019/05

 Times Cited Count:3 Percentile:32.71(Physics, Nuclear)

no abstracts in English

Journal Articles

Role of breakup processes in deuteron-induced spallation reactions at 100-200 MeV/nucleon

Nakayama, Shinsuke; Furutachi, Naoya; Iwamoto, Osamu; Watanabe, Yukinobu*

Physical Review C, 98(4), p.044606_1 - 044606_8, 2018/10

 Times Cited Count:6 Percentile:21.88(Physics, Nuclear)

Use of deuteron-induced spallation reactions at intermediate energies has recently been proposed for transmutation of several long-lived fission products (LLFPs). In the design study of a transmutation system using a deuteron primary beam, accurate cross section data of deuteron-induced reactions on the LLFPs are indispensable. In the present study, production cross sections of residual nuclei in the deuteron-induced reactions on $$^{93}$$Zr and $$^{107}$$Pd at $$100-200$$ MeV/nucleon are analyzed using DEURACS, in which the breakup processes are explicitly taken into account. The calculated values reproduced the experimental data quantitatively well. From a component-by-component analysis, it was found that the components of nucleon absorption make the significant contributions to residual nuclei production. This result strongly indicates that consideration of the breakup processes is essentially important to predict production of residual nuclei in deuteron-induced reactions.

Journal Articles

Activation in injection area of J-PARC 3-GeV rapid cycling synchrotron and its countermeasures

Yamamoto, Kazami; Yamakawa, Emi*; Takayanagi, Tomohiro; Miki, Nobuharu*; Kamiya, Junichiro; Saha, P. K.; Yoshimoto, Masahiro; Yanagibashi, Toru*; Horino, Koki*; Nakanoya, Takamitsu; et al.

ANS RPSD 2018; 20th Topical Meeting of the Radiation Protection and Shielding Division of ANS (CD-ROM), 9 Pages, 2018/08

The existing beam power of the J-PARC Rapid Cycling Synchrotron is up to 500 kW, and higher radiation doses are concentrated in the injection area. These activations are caused by the interaction between the foil and the beam. To reduce dose exposure to workers near the injection point, we study a new design of the injection scheme. Experience has shown that eddy currents are generated in the metal flange near the magnet owing to the pulsed magnetic field, and the temperature exceeds 100 degrees C. The shield installed in the new injection system needs to have a layer structure, in which an insulator is inserted between iron shields to reduce the eddy current. From the results of the shielding calculation, even if 1 mm of polyethylene was inserted between two 9-mm-thick SUS 316 plates, which serve as shielding material, the shielding performance was reduced only about 5%, and we confirmed that it would function well.

Journal Articles

Development of laser system for a proof-of-principle experiment of laser stripping injection

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Inoue, Shunsuke*; Sato, Atsushi*; Suganuma, Kazuaki; Yamane, Isao*; Kinsho, Michikazu; Irie, Yoshiro*

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.811 - 815, 2018/08

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme can realize high intensity proton beam but the uncontrolled beam losses occur by scattering at the foil. Additionally, the beam collision at the foil may cause the break itself. Therefore, a new injection scheme for higher intensity is needed as an alternative to the foil. We newly propose and develop a laser stripping injection scheme. At the first step, we propose a proof-of-principle (POP) experiment of the scheme in J-PARC and develop a laser system. In this presentation, we will introduce the laser stripping injection scheme and describe an overview of a POP experiment. We will report a current status of the laser system.

Journal Articles

Development of a high-efficiency proton recoil telescope for D-T neutron fluence measurement

Tanimura, Yoshihiko; Yoshizawa, Michio

Radiation Protection Dosimetry, 180(1-4), p.417 - 421, 2018/08

 Times Cited Count:0 Percentile:100(Environmental Sciences)

A high efficiency proton recoil telescope (PRT), which consists of a radiator, a $$Delta$$E detector and an E detector, was developed to determine the neutron fluence in the 14.8 MeV mono-energetic neutron field at the FRS. A 2 mm thick plastic scintillation detector was employed as the radiator to increase the detection efficiency and compensate the energy loss of the recoil proton in the radiator. A thin and a thick silicon detectors with 150 $$mu$$m and 3 mm thick sensitive layers were employed as the $$Delta$$E and E detectors, respectively. The detection efficiency was evaluated by the neutron measurements in the 14.8 MeV field for the distances from the radiator to E detector of 50 mm, 100 mm and 150 mm. The detection efficiency increases up to 3.7 $$times$$ 10$$^{-3}$$ with the decrease in the distance, which is roughly a few orders of magnitude greater than those of common PRTs. These detection efficiencies are high enough to determine the neutron fluence at the 14.8 MeV field within a few hours.

Journal Articles

Joint Session of Nuclear Data Subcommittee and Sigma Special Advisory Committee; Present status and future of nuclear data evaluation code in Japan, 3; Development of DEURACS for prediction of deuteron-induced reaction cross section

Nakayama, Shinsuke

Kaku Deta Nyusu (Internet), (120), p.19 - 25, 2018/06

Toward development of accurate deuteron nuclear data, we have been developing a computational code dedicated for the deuteron-induced reaction, called DEURACS. The author presented the developmental status and the future outlook of DEURACS in the joint session of nuclear data subcommittee and sigma special advisory committee, and contributed the outline of the presentation to Nuclear Data News. From our preceding work, it has become possible to predict the $$(d,xn)$$ reactions on light nuclei and the $$(d,xt)$$ reactions. These reactions are important in relation to evaluation of neutron sources and tritium production, respectively. In the future, we plan to improve theoretical models implemented in DEURACS for accurate prediction of nuclide production cross-section on medium-heavy nuclei.

Journal Articles

Systematic shell-model study of $$beta$$-decay properties and Gamow-Teller strength distributions in $$A {approx} 40$$ neutron-rich nuclei

Yoshida, Sota*; Utsuno, Yutaka; Shimizu, Noritaka*; Otsuka, Takaharu*

Physical Review C, 97(5), p.054321_1 - 054321_17, 2018/05

 Times Cited Count:9 Percentile:12.44(Physics, Nuclear)

no abstracts in English

Journal Articles

Cross section measurement in J-PARC for neutronics of the ADS

Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Hiroki

Proceedings of 13th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '17) (Internet), p.396 - 402, 2018/05

no abstracts in English

Journal Articles

Theoretical model analysis of $$(d,xn)$$ reactions on $$^7$$Li at 25, 40, and 102 MeV

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

JAEA-Conf 2017-001, p.135 - 140, 2018/01

In recent years, the demand for intense neutron sources has been increasing in various applications such as nuclear transmutation of high-level radioactive waste and medical radioisotopes production. Deuteron accelerator-based neutron sources are promised as one of the candidates. Therefore, we have developed a code system dedicated for the deuteron-induced reactions, called DEURACS. In the present work, we focus on deuteron-induced neutron production from $$^7$$Li target. The calculated double differential cross sections for $$(d,xn)$$ reactions at incident energies of 25, 40, and 102 MeV are compared with the measured ones, and the applicability of DEURACS is discussed.

Journal Articles

Theoretical model analysis of composite-particle emission from deuteron-induced reactions

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

JAEA-Conf 2017-001, p.91 - 96, 2018/01

Toward evaluation of deuteron nuclear data, we have been developing a code system dedicated for the deuteron-induced reactions, called DEURACS. In the present work, we make an improvement in DEURACS and apply it to composite-particle emission from deuteron-induced reactions. The calculation using DEURACS reproduces the experimental double-differential cross sections of $$(d,xd)$$, $$(d,xt)$$, $$(d,x^3 {rm He})$$, and $$(d,xalpha)$$ reactions on $$^{27}$$Al and $$^{58}$$Ni at incident energy of 80 MeV quantitatively well. From the results of the analyses, it is shown that the treatment of inelastic scattering and pick-up reaction processes is important in the calculation of deuteron-induced composite-particle emission.

Journal Articles

Current status of pulsed spallation neutron source of J-PARC

Takada, Hiroshi

JAEA-Conf 2017-001, p.51 - 56, 2018/01

A pulsed spallation neutron source of Japan Proton Accelerator Research Complex (J-PARC) is aimed at promoting a variety of cutting-edge materials researches at state-of-the-art neutron instruments with neutrons generated by a 3-GeV proton beam with a power of 1-MW at a repetition rate of 25 Hz. In 2015, for the first time it received 1-MW equivalent proton beam pulse, and the beam power for user program was ramped up to 500 kW. The moderator system of the neutron source was optimized to use (1) 100% para-hydrogen for increasing pulse peak intensity with decreasing pulse tail, (2) cylindrical shape with 14 cm diam. $$times$$ 12 cm long for providing high intensity neutrons to wide neutron extraction angles of 50.8 degrees, (3) neutron absorber made from Ag-In-Cd alloy to make pulse widths narrower and pulse tails lower. As a result, it gives highest intensity pulsed neutrons per incident proton in the world. Towards the goal to achieve the target operation at 1-MW for 5000 h in a year, efforts to mitigate cavitation damages at the target vessel front with injecting gas micro-bubbles into the mercury target are under way. Also, improvement of structural target vessel design is an urgent issue since there was failure twice at the water shroud of the mercury target due to the thermal stress during operating periods at 500 kW in 2015.

Journal Articles

Laser storage ring with high power for realization of laser stripping injection

Harada, Hiroyuki; Yamane, Isao*; Saha, P. K.; Suganuma, Kazuaki; Kinsho, Michikazu; Irie, Yoshiro*; Kato, Shinichi

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.684 - 688, 2017/12

The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme can realize high intensity proton beam but the uncontrolled beam losses are caused by scattering between beams and the foil. Additionally, the collision may occur the foil beak. Therefore, a new injection scheme for higher intensity is needed as an alternative to the foil. In the J-PARC 3GeV RCS, we newly propose and develop a laser stripping injection scheme. However, it is necessary that laser power is two order higher than latest laser one. To realize this big issue, we develop the laser storage ring, which can provide laser pulse of high repetition rate by recycling one. In this presentation, we will introduce the laser stripping injection scheme and describe the concept of the laser storage ring with high repetition rate and report the current status.

370 (Records 1-20 displayed on this page)