研究者詳細 - 清水　裕彦

Current status of the polarized La target development for T-violation search with slow neutron Open Access

Ide I., Fujita M., Hotta H., Iinuma M., Ikeda Y., Ito Y., Iwata T., Kitaguchi M., Kohri H., Miura D., Miyachi Y., Okudaira T., Shimizu H.M., Takanashi Y., Yosoi M.

Proceedings of Science 433 巻 2023年8月

出版者・発行元：Proceedings of Science

We are addressing the development of a polarized lanthanum (139La) target by applying a standard dynamic nuclear polarization (DNP) technique to a single crystal of lanthanum aluminate (LaAlO<inf>3</inf>) doped with neodymium ions (Nd3+), which is very attractive to search for violating effects of the time-reversal invariance with neutrons. The use of the LaAlO<inf>3</inf> crystals as target material is very crucial to extend the spin-lattice relaxation time (T<inf>1</inf>) through the optimization of the Nd3+ concentration. We have almost established a method for precise control of the Nd3+ amount and this method has allowed us to grow the crystal with 0.01 mol% concentration differently from the 0.05 mol% reached before. Simple DNP experiments using a single-shot dewar at 1.3 K and 2.3 T allowed the evaluation of the T<inf>1</inf> and the maximum polarization of these crystals. By that we have found that the 0.01 mol% concentration is the best one among the crystals tested in the past. Both, T<inf>1</inf> and the maximum polarization of the 0.01 mol% crystal, have not been exactly obtained because of the long relaxation time, Thus, the preparation of a new DNP system is in progress toward DNP experiments for long-term measurement.

DOI： 10.22323/1.433.0038

Angular distribution of γ rays from a neutron-induced p -wave resonance of Xe 132 Open Access

Okudaira T., Tani Y., Endo S., Doskow J., Fujioka H., Hirota K., Kameda K., Kimura A., Kitaguchi M., Luxnat M., Sakai K., Schaper D.C., Shima T., Shimizu H.M., Snow W.M., Takada S., Yamamoto T., Yoshikawa H., Yoshioka T.

Physical Review C 107 巻 ( 5 ) 2023年5月

出版者・発行元：Physical Review C

A neutron-energy dependent angular distribution was measured for individual γ rays from the 3.2 eV p-wave resonance of Xe131+n, that shows enhanced parity violation owing to a mixing between s- and p-wave amplitudes. The γ-ray transitions from the p-wave resonance were identified, and the angular distribution with respect to the neutron momentum was evaluated as a function of the neutron energy for 7132 keV γ rays, which correspond to a transition to the 1807 keV excited state of Xe132. The angular distribution is considered to originate from the interference between s- and p-wave amplitudes, and will provide a basis for a quantitative understanding of the enhancement mechanism of the fundamental parity violation in compound nuclei.

DOI： 10.1103/PhysRevC.107.054602

Displacement-noise-free interferometeric gravitational-wave detector using unidirectional neutrons with four speeds Open Access

Iwaguchi S., Nishizawa A., Chen Y., Kawasaki Y., Ishikawa T., Kitaguchi M., Yamagata Y., Wu B., Shimizu R., Umemura K., Tsuji K., Shimizu H., Michimura Y., Kawamura S.

Physics Letters Section A General Atomic and Solid State Physics 458 巻 2023年1月

出版者・発行元：Physics Letters Section A General Atomic and Solid State Physics

For further gravitational wave (GW) detections, it is significant to invent a technique to reduce all kinds of mirror displacement noise dominant at low frequencies for ground-based detectors. The neutron displacement-noise-free interferometer (DFI) is one of the tools to reduce all the mirror displacement noise at lower frequencies. In this paper, we describe a further simplified configuration of a neutron DFI in terms of neutron incidence direction. In the new configuration, neutrons enter the interferometer with unidirectional incidence at four speeds as opposed to two bidirectional incidences of opposite directions at two speeds as reported previously. This simplification of the neutron DFI is significant for proof-of-principle experiments.

DOI： 10.1016/j.physleta.2022.128581

Status of the new muonic helium atom HFS measurements at J-PARC MUSE Open Access

Strasser P., Fukumura S., Ino T., Iwai R., Kanda S., Kawamura S., Kitaguchi M., Nishimura S., Oku T., Okudaira T., Seo S., Shimizu H.M., Shimizu K., Shimomura K., Tada H., Tanaka T., Torii H.A., Yamauchi H., Yasuda H.

Journal of Physics Conference Series 2462 巻 ( 1 ) 2023年

出版者・発行元：Journal of Physics Conference Series

Measurements of the muonic helium atom hyperfine structure (HFS) are a sensitive tool to test the theory of three-body atomic systems and bound-state quantum electrodynamics (QED) and to determine fundamental constants of the negative muon magnetic moment and mass. The world's most intense pulsed negative muon beam at J-PARC MUSE brings an opportunity to improve previous measurements and test further CPT invariance by comparing the magnetic moments and masses of positive and negative muons. Test measurements at D-line are now in progress utilizing MuSEUM apparatus at zero field. The first results already have better accuracy than previous measurements in the 1980s. Also, the investigation of a new experimental approach to improve HFS measurements by repolarizing muonic helium atoms using a spin-exchange optical pumping (SEOP) technique was started. If successful, this would drastically improve the measurement accuracy.

DOI： 10.1088/1742-6596/2462/1/012023

139La(n,γ)140La*反応における中性子スピンとγ線運動量の角相関 Open Access

奥泉舞桜, 奥平琢也, 伊東佑起, 遠藤駿典, 奥隆之, 亀田健斗, 北口雅暁, 木村敦, 酒井健二, 嶋達志, 清水裕彦, 高田秀佐, 藤家拓大, 藤岡宏之, 吉岡瑞樹, 吉川大幹, NOPTREXコラボレーション

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 2184 - 2184 2023年

Hybrid-SEOPによる偏極ミューオニックヘリウム生成 Open Access

福村省三, 猪野隆, 奥隆之, 奥平琢也, 神田聡太郎, 北口雅暁, 清水裕彦, 下村浩一郎, 鳥居寛之, 西村昇一郎

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 434 - 434 2023年

J-PARC/BL05における中性子寿命測定実験：γ線背景事象のグローバルフィット Open Access

市川豪, 不破康裕, 長谷川拓郎, 広田克也, 星野公邦, 細川律也, 猪野隆, 岩下芳久, 北口雅暁, 古賀淳, 松崎俊, 三島賢二, 茂木駿紀, 音野瑛俊, 關義親, 関場大一郎, 嶋達志, 清水春樹, 清水裕彦, 角直幸, 角野浩史, 谷田征輝, 山下了, 吉岡瑞樹

日本物理学会講演概要集 78.2 巻 ( 0 ) 頁： 268 - 268 2023年

中性子小角散乱による未知相互作用探索のための重水素吸蔵Vナノ粒子開発 Open Access

近藤亮太, 廣本政之, 嶋達志, 中部倫太郎, 清水裕彦, 北口雅暁, 猪野隆, 三島賢二, 広田克也, 吉岡瑞樹

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 451 - 451 2023年

J-PARC/BL05における中性子寿命測定実験：高統計データを用いた信号抽出効率における系統誤差評価 Open Access

細川律也, 不破康裕, 長谷川拓郎, 広田克也, 星野公邦, 市川豪, 猪野隆, 岩下芳久, 北口雅暁, 古賀淳, 松崎俊, 三島賢二, 茂木駿紀, 音野瑛俊, 關義親, 関場大一郎, 嶋達志, 清水春樹, 清水裕彦, 角直幸, 角野浩史, 谷田征輝, 山下了, 吉岡瑞樹

日本物理学会講演概要集 78.2 巻 ( 0 ) 頁： 269 - 269 2023年

J-PARC/BL05における中性子寿命測定実験：検出器シミュレーションにおける実験結果再現性の向上と検出効率における系統誤差の再評価 Open Access

細川律也, 不破康裕, 長谷川拓郎, 広田克也, 市川豪, 猪野隆, 岩下芳久, 北口雅暁, 古賀淳, 松崎俊, 三島賢二, 茂木駿紀, 音野瑛俊, 關義親, 関場大一郎, 嶋達志, 清水春樹, 清水裕彦, 角直幸, 角野浩史, 谷田征輝, 山下了, 矢野浩大, 吉岡瑞樹

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 211 - 211 2023年

J-PARC/BL05における中性子寿命測定実験：中性子寿命解析の結果と現状 Open Access

茂木駿紀, 不破康裕, 長谷川拓郎, 広田克也, 星野公邦, 細川律也, 市川豪, 猪野隆, 岩下芳久, 北口雅暁, 古賀淳, 松崎俊, 三島賢二, 音野瑛俊, 關義親, 関場大一郎, 嶋達志, 清水春樹, 清水裕彦, 角直幸, 角野浩史, 谷田征輝, 山下了, 吉岡瑞樹

日本物理学会講演概要集 78.2 巻 ( 0 ) 頁： 270 - 270 2023年

J-PARC/BL05における中性子寿命測定実験：中性子寿命解析の最新結果 Open Access

茂木駿紀, 不破康裕, 長谷川拓郎, 広田克也, 細川律也, 市川豪, 猪野隆, 岩下芳久, 北口雅暁, 古賀淳, 松崎俊, 三島賢二, 音野瑛俊, 關義親, 関場大一郎, 嶋達志, 清水春樹, 清水裕彦, 角直幸, 角野浩史, 谷田征輝, 山下了, 吉岡瑞樹

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 212 - 212 2023年

J-PARC/BL05における中性子寿命測定実験：γ線背景事象測定と系統誤差見積もりの改善 Open Access

市川豪, 不破康裕, 長谷川拓郎, 広田克也, 細川律也, 猪野隆, 岩下芳久, 北口雅暁, 古賀淳, 松崎俊, 三島賢二, 茂木駿紀, 音野瑛俊, 關義親, 関場大一郎, 嶋達志, 清水春樹, 清水裕彦, 角直幸, 角野浩史, 谷田征輝, 山下了, 矢野浩大, 吉岡瑞樹

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 210 - 210 2023年

時間反転対称性の破れの探索に向けた偏極La核偏極開発の現状 Open Access

伊東佑起, 井出郁央, 南部太郎, 石崎貢平, 堀田大稀, 清水裕彦, 北口雅暁, 奥平琢也, 松下琢, 飯沼昌隆, 郡英輝, 藤田全基, 池田陽一, 谷口貴紀, 高田秀佐, 岩田高広, 宮地義之, 高梨雄矢, 三浦大輔, NOPTREX Collaboration

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 435 - 435 2023年

重力波検出のための変位雑音フリー中性子干渉計の開発(8) Open Access

岩口翔輝, 川﨑祐輝, 石川智浩, 西澤篤志, 山形豊, 北口雅暁, 小林和宏, 大西崇文, 清水龍真, 梅村来未, 辻健志, 清水裕彦, 道村唯太, 川村静児

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 659 - 659 2023年

複合核を用いた時間反転対称性の破れの探索とそれに向けた複合核反応の基礎研究 Open Access

奥平琢也, 伊東佑起, 井出郁央, 遠藤駿典, 奥隆之, 奥泉舞桜, 後藤優, 亀田健斗, 北口雅暁, 木村敦, 酒井健二, 嶋達志, 清水裕彦, 南部太郎, 西村岳太郎, 藤家拓大, 藤岡宏之, 吉岡瑞樹, 吉川大幹, NOPTREXコラボレーション

日本物理学会講演概要集 78.1 巻 ( 0 ) 頁： 438 - 438 2023年

Measurement of the transverse asymmetry of γ rays in the Sn 117 (n,γ) Sn 118 reaction Open Access

Endo S., Okudaira T., Abe R., Fujioka H., Hirota K., Kimura A., Kitaguchi M., Oku T., Sakai K., Shima T., Shimizu H.M., Takada S., Takahashi S., Yamamoto T., Yoshikawa H., Yoshioka T.

Physical Review C 106 巻 ( 6 ) 2022年12月

出版者・発行元：Physical Review C

Largely enhanced parity-violating effects observed in compound resonances induced by epithermal neutrons are currently attributed to the mixing of parity-unfavored partial amplitudes in the entrance channel of the compound states. Furthermore, it is proposed that the same mechanism that enhances the parity violation also enhances the breaking of time-reversal invariance in the compound nucleus. The entrance-channel mixing induces energy-dependent spin-angular correlations of individual γ rays emitted from the compound nuclear state. For a detailed study of the mixing model, the γ-ray yield in the reaction of Sn117(n,γ)Sn118 was measured using a pulsed beam of polarized epithermal neutrons and Ge detectors. An angular dependence of asymmetric γ-ray yields for the orientation of the neutron polarization was observed.

DOI： 10.1103/PhysRevC.106.064601

Displacement-noise-free neutron interferometer for gravitational wave detection using a single Mach-Zehnder configuration Open Access

Iwaguchi S., Nishizawa A., Chen Y., Kawasaki Y., Kitaguchi M., Morimoto T., Ishikawa T., Wu B., Watanabe I., Shimizu R., Shimizu H., Michimura Y., Kawamura S.

Physics Letters Section A General Atomic and Solid State Physics 441 巻 2022年7月

出版者・発行元：Physics Letters Section A General Atomic and Solid State Physics

The improvement of sensitivity to gravitational waves (GWs) at lower frequencies is still challenging on account of displacement noise. One of the solutions is the neutron displacement-noise-free interferometer (DFI). We focus on a simplification of the detector configuration by taking advantage of the ability to adjust the neutron speed depending on the configuration. The new configuration consists of two beamsplitters and two mirrors, which constitute a single Mach-Zehnder interferometer (MZI). It is simpler than the configuration with two MZIs in previous research. All displacement noise of mirrors and beamsplitters can be canceled in the frequency domain. This cancellation can be explained intuitively using a phasor diagram.

DOI： 10.1016/j.physleta.2022.128150

A novel nuclear emulsion detector for measurement of quantum states of ultracold neutrons in the Earth's gravitational field Open Access

Muto N., Abele H., Ariga T., Bosina J., Hino M., Hirota K., Ichikawa G., Jenke T., Kawahara H., Kawasaki S., Kitaguchi M., Micko J., Mishima K., Naganawa N., Nakamura M., Roccia S., Sato O., Sedmik R.I.P., Seki Y., Shimizu H.M., Tada S., Umemoto A.

Journal of Instrumentation 17 巻 ( 7 ) 2022年7月

出版者・発行元：Journal of Instrumentation

Hypothetical short-range interactions could be detected by measuring the wavefunctions of gravitationally bound ultracold neutrons (UCNs) on a mirror in the Earth's gravitational field. Searches for them with higher sensitivity require detectors with higher spatial resolution. We developed and have been improving an UCN detector with a high spatial resolution, which consists of a Si substrate, a thin converter layer including 10B4C, and a layer of fine-grained nuclear emulsion. Its resolution was estimated to be less than 100 nm by fitting tracks of either 7Li nuclei or α-particles, which were created when neutrons interacted with the 10B4C layer. For actual measurements of the spatial distributions, the following two improvements were made. The first improvement was to establish a method to align microscopic images with high accuracy within a wide region of 65 mm × 0.2 mm. We created reference marks of 1 μm and 5 μm diameter with an interval of 50 μm and 500 μm, respectively, on the Si substrate by electron beam lithography and realized a position accuracy of less than 30 nm. The second improvement was to build a holder for the detector that could maintain the atmospheric pressure around the nuclear emulsion to utilize it under a vacuum during exposure to UCNs. The intrinsic resolution of the improved detector was estimated to be better than 0.56(8) μm by evaluating the blur of a transmission image of a gadolinium grating taken by cold neutrons. The evaluation included the precision of the gadolinium grating. A test exposure was conducted to obtain the spatial distribution of UCNs in the quantized states on a mirror in the Earth's gravitational field. The distribution was obtained, fitted with the theoretical curve, and turned out to be reasonable for UCNs in quantized states when we considered a blurring of 6.9 μm. The blurring was well explained as a result of neutron refraction due to the large surface roughness on the upstream side of the Si substrate. By using a double-side-polished Si substrate, a resolution of less than 0.56 μm is expected to be achieved for UCNs.

DOI： 10.1088/1748-0221/17/07/P07014