Feasibility study of magnetic-domain observation by means of non-resonant magnetic X-ray diffraction

Inami, Toshiya*; Shobu, Takahisa; Ishii, Kenji*

IEEE Transactions on Magnetics, 57(3, Part 2), p.6400105_1 - 6400105_5, 2021/03

https://doi.org/10.1109/TMAG.2020.3046006

Negative muonium ion production with a C12A7 electride film

Otani, Masashi*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Matoba, Shiro*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Yamazaki, Takayuki*; Hasegawa, Kazuo; et al.

Journal of Physics; Conference Series, 1350, p.012067_1 - 012067_6, 2019/12

https://doi.org/10.1088/1742-6596/1350/1/012067

Negative muonium atom (ee, Mu) has unique features stimulating potential interesting for several scientific fields. Since its discovery in late 1980's in vacuum, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has relatively low-work function (2.9 eV). In this paper, the negative muonium production measurement with several materials including a C12A7 electride film will be presented. Measured production rate of the Mu were 10/s for all the Al, electride, and SUS target. Significant enhancement on electride target was not observed, thus it is presumed that the surface condition should be more carefully treated. There was no material dependence of the Mu averaged energy: it was 0.20.1keV.

Development of the longitudinal beam profile monitor with high time resolution for realization of low-emittance muon beam in the J-PARC E34 muon g-2/EDM experiment

Yotsuzuka, Mai*; Iijima, Toru*; Iinuma, Hiromi*; Inami, Kenji*; Otani, Masashi*; Kawamura, Naritoshi*; Kitamura, Ryo; Kondo, Yasuhiro; Saito, Naohito; Shimomura, Koichiro*; et al.

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.814 - 817, 2019/07

https://www.pasj.jp/web_publish/pasj2019/proceedings/PDF/THPI/THPI031.pdf

The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, thermal muonium is produced and ionized by laser resonance to generate ultra-slow muons, which are then accelerated in a multistage muon linac. In order to satisfy the experimental requirements, suppression of the emittance growth during the acceleration is necessary. Because the main cause of the emittance growth is beam mismatching between the accelerating stages, the transverse and longitudinal beam monitoring is important. The longitudinal beam monitor has to measure the bunch length with the resolution equivalent to tens of picoseconds, which is 1% of the acceleration phase of 324 MHz. In addition, it should be sensitive to single muon because the beam intensity is limited during the commissioning phase. To realize above requirements, we are developing a longitudinal beam monitor with a micro channel plate, and the test bench to evaluate the monitor performance. So far, the time resolution of the beam monitor was obtained to be 65 ps in RMS including the jitter on the test bench. We also succeeded in measuring the longitudinal bunch size of the muon beam accelerated by RFQ using the beam monitor. In this paper, the results of the performance evaluation for this beam monitor are reported.

A Bunch structure measurement of muons accelerated by RFQ using a longitudinal beam-profile monitor with high time resolution

Sue, Yuki*; Iijima, Toru*; Inami, Kenji*; Yotsuzuka, Mai*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Otani, Masashi*; Hasegawa, Kazuo; et al.

Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.37 - 40, 2019/06

https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM2

The result of bunch size measurement of muon accelerated by RFQ up to 89 keV is presented in this paper. A four-stage muon linac for precise measurement of muon property is under construction in the J-PARC. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured in 2017. As one of the remaining issues for the beam diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the microchannel plate is under development. The time resolution of the monitor aims to be around 30 to 40 ps corresponding to 1% of a period of an operating frequency of the accelerator, which is 324 MHz. On November 2018, the bunch size of accelerated negative muonium ion of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The measured bunch width is ns, which is consistent with the simulation.

Instrumental upgrades of the RIXS spectrometer at BL11XU at SPring-8

Ishii, Kenji; Jarrige, I.*; Yoshida, Masahiro*; Ikeuchi, Kazuhiko*; Inami, Toshiya; Murakami, Yoichi*; Mizuki, Junichiro

Journal of Electron Spectroscopy and Related Phenomena, 188, p.127 - 132, 2013/06

https://doi.org/10.1016/j.elspec.2012.12.003

Critical competition between two distinct orbital-spin ordered states in perovskite vanadates

Fujioka, Jun*; Yasue, Toshio*; Miyasaka, Shigeki*; Yamazaki, Yuichi*; Arima, Takahisa*; Sagayama, Hajime*; Inami, Toshiya; Ishii, Kenji; Tokura, Yoshinori*

Physical Review B, 82(14), p.144425_1 - 144425_12, 2010/10

https://doi.org/10.1103/PhysRevB.82.144425

Development of maintenance technology for rotating equipment; Condition based maintenance by shock pulse method

Takeuchi, Kenji; Sanyoshi, Hirotaka; Fukuari, Yoshihiro; Inami, Shinichi

Proceedings of 7th International Conference on NDE in relation to Structural Integrity for Nuclear and Pressurized Components (CD-ROM), p.37 - 44, 2010/00

In the Tokai Reprocessing Plant (TRP), lots of blowers are used for enclosing radioactive materials in a controlled area, and pumps are used for circulating cooling water to keep temperature under appropriate conditions of vessels, which contain high-level radioactive liquid waste. These rotating equipments play an important role in safety management of the nuclear facilities, where they are required stable conditions all the time. To improve the reliability of rotating equipments, the condition based maintenance for detecting the deterioration is one of the effective measures. According to the analyses of the past maintenance data obtained in TRP, it has been found that about 90% troubles related to the rotating equipment are caused in the bearing works, in which the lubrication was defective in almost every case. So, it is very important for stable operation of the rotating equipment to monitor the lubrication conditions in bearings. The vibration method facilitates to detect defects and abrasion of bearings by measuring a vibration signal. However, this method has a disadvantage that quantitative management for the lubrication conditions of bearings is not possible. Therefore, the shock pulse method, which is widely used for diagnosis of the bearings, is applied to assess the deterioration of rolling bearing. The shock pulse method can detect the change of the lubrication condition and the presence of defects in bearings, by a pressure wave generated from rotating rolling bearing. The method can also evaluate the oil slick thickness and the condition of deterioration in the bearing. As one of maintenance activities performed after monitoring, replenishment with a suitable amount of oil for a lubricant was able to be conducted with a proper timing. As a result, the number of the troubles on bearings has significantly reduced because proper maintenance for keeping the oil slick thickness can be carried out, which resulted in stable operation of the rotary equipmen

X-ray magnetic circular dichroism of a valence fluctuating state in Eu at high magnetic fields

Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Inami, Toshiya; Owada, Kenji; Suzuki, Motohiro*; Kawamura, Naomi*; Mitsuda, Akihiro*; Wada, Hirofumi*

Physical Review Letters, 103(4), p.046402_1 - 046402_4, 2009/07

https://doi.org/10.1103/PhysRevLett.103.046402

X-ray magnetic circular dichroism (XMCD) at the Eu L edge in two compounds exhibiting valence fluctuation, namely EuNi(SiGe) and EuNiP, has been investigated at high magnetic fields of up to 40T. A distinct XMCD peak corresponding to the trivalent state (Eu), whose ground state is nonmagnetic (J = 0), was observed in addition to the main XMCD peak corresponding to the magnetic (J = 7/2) divalent state (Eu). This result indicates that the 5 electrons belonging to both valence states are magnetically polarized. It was also found that the ratio (3+)/(2+) between the polarization of 5 electrons() in the Eu state and that of Eu depends on the material. The possible origin of the XMCD and an explanation of the material dependence of (3+)/(2+) are discussed in terms of hybridization between the conduction electrons and the f electrons.

Interlaboratory comparison of positron annihilation lifetime measurements

Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.

Materials Science Forum, 607, p.248 - 250, 2009/00

So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring the equivalency and reliability of data from different laboratories. As a first, we conducted an interlaboratory comparison of PAL measurements for metal, polymer and silica glass with agreed procedures for data recording and analysis. The PAL data recorded at different laboratories were analyzed with a single lifetime component for the metal sample and with three components for the others, respectively. Based on the results of the reported positron and ortho-positronium lifetimes, the possible sources of the uncertainties in the PAL measurements are discussed. To reduce the effect of scattered rays, a lead shield was placed between the detectors. The uncertainty was significantly decreased, signifying that placing lead shields between the detectors effectively reduced the false signals due to the scattered rays.

Interlaboratory comparison of positron annihilation lifetime measurements for synthetic fused silica and polycarbonate

Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.

Journal of Applied Physics, 104(2), p.026102_1 - 026102_3, 2008/07

https://doi.org/10.1063/1.2957074

Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.