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-ray fieldsKaburagi, Masaaki; Kamada, Kei*; Ishii, Junya*; Matsumoto, Tetsuro*; Manabe, Seiya*; Masuda, Akihiko*; Harano, Hideki*; Kato, Masahiro*; Shimazoe, Kenji*
Journal of Instrumentation (Internet), 19(11), p.P11019_1 - P11019_16, 2024/11
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Kuriyama, Yasutoshi*; Iwashita, Yoshihisa*; Fuwa, Yasuhiro; Tongu, Hiromu*; Hayano, Hitoshi*; Geng, R. L.*
Journal of Instrumentation (Internet), 19(9), p.P09037_1 - P09037_15, 2024/09
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Wada, Motoi*; Shibata, Takanori*; Shinto, Katsuhiro
Journal of Instrumentation (Internet), 19(2), p.C02019_1 - C02019_7, 2024/02
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)A negative hydrogen (H
) ion source with the plasma excited by 2 MHz radio frequency (RF) power serves as the beam source for the Japan Proton Accelerator Research Complex (J-PARC). We have been studying the H ion beam intensity modulation at the frequency of plasma excitation RF power since we have found the beam carried the fluctuation at 2 MHz after the RFQ linac. Higher frequency components were found present in the peripheral region of the plasma, and the highspeed emittance measurement system developed to clarify the change of the beam in phase space revealed the existence of diverging halo component oscillating at 2 MHz. The fluctuation amplitude at the beam center was less than about 20%, while there was observed the component oscillating at 4 MHz. The 4 MHz component seems related to the production of high energy electrons by the RF antenna as the intensity of the RF induction electric field takes the maximum twice in each cycle. On the other hand, the direction of RF magnetic field and the direction of electron flow change at 2 MHz frequency. Thus, H ion formation mechanisms in the ion source can be estimated through precisely characterizing the extracted H ion beam. The H ion beam fluctuation can be observed in the H ion current measured with a Faraday cup. Before introducing Cs, the measured beam current showed the fluctuation at 4 MHz frequency when the axial magnetic field correction (AMFC) coil was turned off. The main fluctuation frequency changed to 2 MHz as the voltage to excite the coil to induce AMFC was increased. Injection of Cs into the ion source increased the H ion current, while the 4 MHz component nearly disappeared for both cases of AMFC on and AMFC off. Possible mechanisms responsible for diminishing 4 MHz fluctuation component by Cs injections are discussed.
Shibata, Takanori*; Shinto, Katsuhiro; Nammo, Kesao*; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Oguri, Hidetomo; Ishida, Masaki*; Wada, Motoi*
Journal of Instrumentation (Internet), 19(1), p.C01009_1 - C01009_8, 2024/01
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)From Nov. 2020 to Apr. 2021, the continuous ion source operation for 3,651 hours (5 months) was achieved. As the lifetime of the RF ion source is mainly limited by failure on the enamel coating of the RF antenna, detailed evaluation of the antenna surface is required to ensure feasibility of the further extension of the operation time. In the present study, surface discoloration on the RF antenna coil observed after the 5 months operation is investigated by application of digital microscope and SEM/EDS analyses. The material mapping and the line spectrum obtained by the EDS analysis show that depositions of the sputtered source chamber wall materials and the injected cesium on to the enamel coating are the most possible candidate for the discoloration. The dimension measurements of the RF antenna thickness before and after the long-term operation support the idea that the discoloration is due to the deposited materials and hence insulation of the RF antenna coil by enamel coating is maintained. The emittance measurement after the operation also shows that the RF plasma and the beam formations are not affected by the deposition on the antenna.
-II neutrino targetShin, C. D.*; Dodo, Taku; Haga, Katsuhiro; Harada, Masahide; Hasegawa, Shoichi; Kasugai, Yoshimi; Kinoshita, Hidetaka; Masuda, Shiho; Meigo, Shinichiro; Sakai, Kenji; et al.
Journal of Instrumentation (Internet), 18(12), p.T12001_1 - T12001_9, 2023/12
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)
ion sourceUeno, Akira; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Oguri, Hidetomo
Journal of Instrumentation (Internet), 18(8), p.C08002_1 - C08002_8, 2023/08
Times Cited Count：2 Percentile：33.45(Instruments & Instrumentation)On 2020, the stable operation of the J-PARC cesiated RF-driven H ion source (IS) with a 65 keV 110 mA beam, whose emittances were suitable for the radio-frequency quadrupole LINAC, was reported. In the J-PARC IS operation, the stable plasma production with a 50 kW 2 MHz RF power for more than 3 months, an RF power efficiency higher than 2.6 mA/kW and the possibility of the space charge limited beam intensity pulling up by increasing the extraction and acceleration voltages (V
and V
) were proven. The stable operation results with a 69.9 keV 120 mA beam realized by increasing the withstand voltage around the 2 MHz RF matching circuit are presented. The 107.8 mA of the beam was measured inside the emittances used for the RFQ design.
Jameson, R. A.*; Yee-Rendon, B.
Journal of Instrumentation (Internet), 17(12), p.P12011_1 - P12011_11, 2022/12
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)A new application of vane modulation variation in a Radio Frequency Quadrupole (RFQ) cell has been applied that significantly improves beam bunching and longitudinal emittance control to achieve lower longitudinal rms emittance at the RFQ output. This procedure occurs in the individual cells, is independent of the overall design, and therefore is general, affording an extra parameter for beam manipulation. It can be applied besides the usual goals of vane modulation variation, e.g., to achieve higher acceleration efficiency. Examples of the cumulative effects on the overall design are provided to point out further exploration avenues for the designer.
Yee-Rendon, B.; Meigo, Shinichiro; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Iwamoto, Hiroki; Sugawara, Takanori; Nishihara, Kenji
Journal of Instrumentation (Internet), 17(10), p.P10005_1 - P10005_21, 2022/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)To reduce the hazard of minor actinides in nuclear waste, JAEA proposed an accelerator-driven subcritical system (JAEA-ADS). The JAEA-ADS drives a subcritical reactor 800-MWth by 30-MW proton linac delivering the beam to the spallation neutron target inside the reactor. The beam transport to the target (BTT) is required for high-beam power stability and low peak density to ensure the integrity of the beam window. Additionally, the design should have compatible with the reactor design for the maintenance and replacement of the fuel and the beam window. A robust-compact BTT design was developed through massive multiparticle simulations. The beam optics was optimized to guarantee beam window feasibility requirements by providing a low peak density of less than 0.3 
A/mm. Beam stability was evaluated and improved by simultaneously applying the linac's input beam and element errors. The input beam errors to the reactor were based on the beam degradation obtained by implementing fast fault compensation in the linac. Those results show that the BTT fulfills the requirements for JAEA-ADS.
Mori, Airi; Seguchi, Eisaku*; Futemma, Akira; Iwai, Takeyuki*; Sanada, Yukihisa
Journal of Instrumentation (Internet), 17(10), p.P10015_1 - P10015_11, 2022/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*
Journal of Instrumentation (Internet), 16(10), p.C10008_1 - C10008_8, 2021/10
Times Cited Count：4 Percentile：26.64(Instruments & Instrumentation)Adriani, O.*; Tanida, Kiyoshi; RHICf Collaboration*; 17 of others*
Journal of Instrumentation (Internet), 16(10), p.P10027_1 - P10027_16, 2021/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation) rays from 
LiF tile as an inner wall of a neutron-decay detectorKoga, Jun*; Kimura, Atsushi; Okudaira, Takuya*; 12 of others*
Journal of Instrumentation (Internet), 16(2), p.P02001_1 - P02001_13, 2021/02
Times Cited Count：1 Percentile：6.06(Instruments & Instrumentation)Yamamoto, Seiichi*; Nagao, Yuto*; Kurita, Keisuke; Yamaguchi, Mitsutaka*; Kawachi, Naoki*
Journal of Instrumentation (Internet), 16(1), p.P01007_1 - P01007_9, 2021/01
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Luminescence of water during irradiation with particles having energies below the Cerenkov-light threshold was recently found for various types of radiations. However, the relation between the intensities of Cerenkov light and of the luminescence of water at the beam energy below the Cherenkov threshold is not well known. To clarify this point, we measured the produced light irradiating a water sample with electron beams having maximum energies above and below the Cerenkov-light threshold.
Sato, Yuki; Minemoto, Kojiro*; Nemoto, Makoto*; Torii, Tatsuo
Journal of Instrumentation (Internet), 16(1), p.P01020_1 - P01020_18, 2021/01
Times Cited Count：2 Percentile：12.79(Instruments & Instrumentation)Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; et al.
Journal of Instrumentation (Internet), 15(7), p.P07022_1 - P07022_16, 2020/07
Times Cited Count：5 Percentile：27.80(Instruments & Instrumentation)no abstracts in English
Sato, Yuki; Terasaka, Yuta; Ozawa, Shingo*; Tanifuji, Yuta; Torii, Tatsuo
Journal of Instrumentation (Internet), 13(8), p.T08011_1 - T08011_10, 2018/08
Times Cited Count：7 Percentile：31.41(Instruments & Instrumentation)Sato, Yuki; Ozawa, Shingo*; Tanifuji, Yuta; Torii, Tatsuo
Journal of Instrumentation (Internet), 13(3), p.P03001_1 - P03001_8, 2018/03
Times Cited Count：7 Percentile：31.41(Instruments & Instrumentation)-rays at the ANNRI in the MLF of the J-PARCTakada, Shusuke*; Okudaira, Takuya*; Goto, Fumiya*; Hirota, Katsuya*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Nakao, Taro*; Sakai, Kenji; Shimizu, Hirohiko*; et al.
Journal of Instrumentation (Internet), 13(2), p.P02018_1 - P02018_21, 2018/02
Times Cited Count：7 Percentile：31.41(Instruments & Instrumentation)Nakamura, Tatsuya; To, Kentaro; Tsutsui, Noriaki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru
Journal of Instrumentation (Internet), 12(12), p.C12025_1 - C12025_9, 2017/12
Times Cited Count：4 Percentile：19.09(Instruments & Instrumentation)A high-spatial-resolution, large-area position-sensitive scintillation-based neutron detector module has been developed for a new time-of-flight Laue single-crystal diffractometer to be constructed at J-PARC MLF. A first prototype detector implementing commercial 
Li:ZnS screens was produced based on a scintillator/wavelength-shifting fibre technology. The detector exhibited a spatial resolution of 2.5 mm with a neutron-sensitive area of 320 
320 mm
. We report on an initial evaluation of the detector performance, including its spatial resolution, detection efficiency and long-term background measurement, and also provide a brief description of a new neutron instrument.
To, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Yamagishi, Hideshi*
Journal of Instrumentation (Internet), 12(12), p.C12011_1 - C12011_8, 2017/12
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)A neutron-detection element using circular cathode bumps was developed for two-dimensional neutron measurement, and an irradiation experiment was performed using a 
Cf neutron source. The element has triangularly arranged small-sized circular cathode bumps, and the bumps are linked together in the x- and y-directions for the detection of incident neutrons. The element was arranged in the pressure vessel with a fill gas of composition He/(15%)CF
at 0.7 MPa. The detector system using bump cathode element exhibited a two-dimensional uniformity with a response of 10.1%. The average intrinsic spatial resolution was 1.89 mm full width at half maximum in the sensitive region, calculated by taking into account the track lengths of the secondary particles.
