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Journal Articles

Energy-dependent angular distribution of individual $$gamma$$ rays in the $$^{139}$$La($$n, gamma$$)$$^{140}$$La$$^{ast}$$ reaction

Okudaira, Takuya*; Endo, Shunsuke; Fujioka, Hiroyuki*; Hirota, Katsuya*; Ishizaki, Kohei*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Ninomi, Yudai*; Sakai, Kenji; et al.

Physical Review C, 104(1), p.014601_1 - 014601_6, 2021/07

 Times Cited Count:0 Percentile:0.03(Physics, Nuclear)

Journal Articles

Study of neutron-nuclear spin correlation term with a polarized Xe target

Sakai, Kenji; Oku, Takayuki; Okudaira, Takuya; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kakurai, Kazuhisa*; Shimizu, Hirohiko*; Hirota, Katsuya*; et al.

JPS Conference Proceedings (Internet), 33, p.011116_1 - 011116_6, 2021/03

In neutron fundamental physics, study of correlation term $${bf s}cdot{bf I}$$ of a neutron spin $${bf s}$$ and a target nuclear spin $${bf I}$$ is important because $${bf s}cdot{bf I}$$ term interferes to parity non-conserving (PNC) and time reversal non-conserving terms. For this study, a xenon (Xe) is an interesting nucleus because it has been observed an enhancement of PNC effect around neutron resonance peaks, and polarizes up to $$ sim 10^{-1}$$ by using a spin exchange optical pumping (SEOP) method. We would plan to develop a polarized Xe gas target with a compact in-situ SEOP system, and to study $${bf s}cdot{bf I}$$ term by utilizing epithermal neutron beams supplied from a high intense pulsed spallation neutron source. As the first step, we attempted to measure neutron polarizing ability caused by $${bf s}cdot{bf I}$$ term at a 9.6 eV s-wave resonance peak of $$^{129}$$Xe at BL10 in MLF, by detecting change $$Delta R$$ of ratio between neutron transmissions with the polarized and unpolarized Xe target. After demonstrating that our apparatus could detect small change ($$Delta R_{rm DB} , {approx},10^{-2}$$) of neutron transmissions caused by Doppler broadening effect, a signified value of $$Delta R$$ has been obtained as preliminary results. For analyzing the obtained $$Delta R$$ in detail, we are improving our nuclear magnetic resonance and electron paramagnetic resonance systems for evaluating Xe polarization independently of neutron beams.

Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 Times Cited Count:4 Percentile:76.41(Instruments & Instrumentation)

Journal Articles

Measurement of the angular distribution of $$gamma$$-rays after neutron capture by $$^{139}$$La for a T-violation search

Okudaira, Takuya; Shimizu, Hirohiko*; Kitaguchi, Masaaki*; Hirota, Katsuya*; Haddock, C. C.*; Ito, Ikuya*; Yamamoto, Tomoki*; Endo, Shunsuke*; Ishizaki, Kohei*; Sato, Takumi*; et al.

EPJ Web of Conferences, 219, p.09001_1 - 09001_6, 2019/12

Parity violating effects enhanced by up to 10$$^6$$ times have been observed in several neutron induced compound nuclei. There is a theoretical prediction that time reversal (T) violating effects can also be enhanced in these nuclei implying that T-violation can be searched for by making very sensitive measurements. However, the enhancement factor has not yet been measured in all nuclei. The angular distribution of the (n,$$gamma$$) reaction was measured with $$^{139}$$La by using a germanium detector assembly at J-PARC, and the enhancement factor was obtained. From the result, the measurement time to achieve the most sensitive T-violation search was estimated as 1.4 days, and a 40% polarized $$^{139}$$La target and a 70% polarized $$^3$$He spin filter whose thickness is 70 atm$$cdot$$cm are needed. Therefore high quality $$^3$$He spin filter is developed in JAEA. The measurement result of the (n,$$gamma$$) reaction at J-PARC and the development status of the $$^3$$He spin filter will be presented.

Journal Articles

Development of the neutron polarizer for the T-violation search using compound nuclei

Okudaira, Takuya; Oku, Takayuki; Sakai, Kenji; Ino, Takashi*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Shinohara, Takenao; Kakurai, Kazuhisa*; Aizawa, Kazuya; Shimizu, Hirohiko*; et al.

Proceedings of Science (Internet), 356, 5 Pages, 2019/12

The technology development section carries out the development of the neutron polarization device: $$^{3}$$He Spin Filter. It is often used for the fundamental physics region. In order to explain the matter-dominated universe, a time reversal violation is necessary and searches for new physics are conducted in the world. The T-violation search using a polarized neutron beam is planned at J-PARC. A large $$^{3}$$He spin filter is needed to polarize high energy neutrons for the experiment and is developed in JAEA. Recently, we developed the accurate measurement system to evaluate the polarization of $$^{3}$$He and a vacuum system to make the $$^{3}$$He spin filter, and large $$^{3}$$He spin filters for epi-thermal neutron was made using the system. The current status of the development of the $$^{3}$$He spin filter will be talked.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:140 Percentile:99.81(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Angular distribution of $$gamma$$ rays from neutron-induced compound states of $$^{140}$$La

Okudaira, Takuya*; Takada, Shusuke*; Hirota, Katsuya*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Nagamoto, Kosuke*; Nakao, Taro*; Okada, Anju*; Sakai, Kenji; et al.

Physical Review C, 97(3), p.034622_1 - 034622_15, 2018/03

 Times Cited Count:6 Percentile:62.89(Physics, Nuclear)

Journal Articles

Characterization of germanium detectors for the measurement of the angular distribution of prompt $$gamma$$-rays at the ANNRI in the MLF of the J-PARC

Takada, 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:3 Percentile:26.36(Instruments & Instrumentation)

Journal Articles

Removal and recovery of uranium from solid wastes by supercritical carbon dioxide fluid leaching method

Meguro, Yoshihiro; Tomioka, Osamu; Imai, Tomoki*; Fujimoto, Shigeyuki*; Nakashima, Mikio; Yoshida, Zenko; Honda, Tadashi*; Koya, Fumio*; Kitamura, Nobu*; Wada, Ryutaro*; et al.

Proceedings of International Waste Management Symposium 2004 (WM '04) (CD-ROM), 8 Pages, 2004/03

Supercritical CO$$_{2}$$ fluid leaching (SFL) method using supercritical CO$$_{2}$$ fluid containing a complex of HNO$$_{3}$$ - tri-n-butyl phosphate (TBP) was applied to removal of uranium from radioactive solid wastes. Sea sands, incineration ashes and porous alumina bricks were employed as matrixes of simulated solid wastes. Real radioactive incineration ash wastes and firebrick wastes were also subjected to the SFL treatment. It was found that uranium could be efficiently removed from both of the simulated wastes and real wastes by the SFL method. The removal efficiency of uranium from the real waste was lower than that from the corresponding artificial waste. About 1 g and 35 mg of uranium were recovered from 10 g of the real ash waste and 37 g of the real firebrick waste, respectively.

Oral presentation

Study of neutron-nuclear spin correlation term with a polarized xenon target

Sakai, Kenji; Oku, Takayuki; Harada, Masahide; Kai, Tetsuya; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kira, Hiroshi*; Shimizu, Hirohiko*; Hirota, Katsuya*; Okudaira, Takuya*; et al.

no journal, , 

no abstracts in English

Oral presentation

Study of neutron-nuclear spin correlation term with a polarized xenon target

Sakai, Kenji; Oku, Takayuki; Okudaira, Takuya; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke; Hayashida, Hirotoshi*; Shimizu, Hirohiko*; Yamamoto, Tomoki*; Ino, Takashi*; et al.

no journal, , 

In neutron fundamental physics, a study of correlation term $${bf s}cdot{bf I}$$ of a neutron spin s and a target nuclear spin $${bf I}$$ is important because the $${bf s}cdot{bf I}$$ term interferes to parity non-conserving (PNC) and time reversal non-conserving (TRNC) terms. For this study, a xenon (Xe) is an interesting nucleus because it has been observed an enhancement of PNC effect around neutron resonance peaks, and polarizes up to $$10^{-2}sim 10^{-1}$$ by using a spin exchange optical pumping (SEOP) method. We attempted to develop a polarized Xe target in a compact ${it in situ}$ SEOP system and measure neutron polarizing ability caused by the $${bf s}cdot{bf I}$$ term at a 9.6 eV $$s$$-wave resonance peak of $$^{129}$$Xe, by detecting change $$Delta R_P$$ of a ratio between neutron transmissions with the polarized and unpolarized Xe target. As preliminary results, we observed a signified value of $$Delta R_{P} approx 0.01$$ after demonstrating that our apparatus could distinguish Doppler broadening effect as systematic error.

Oral presentation

The Development of the $$^{3}$$He spin filter for the time reversal violation search using compound nuclei at JAEA

Okudaira, Takuya; Oku, Takayuki; Sakai, Kenji; Ino, Takashi*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Shinohara, Takenao; Kakurai, Kazuhisa*; Aizawa, Kazuya; Shimizu, Hirohiko*; et al.

no journal, , 

The technology development section carries out the development of the neutron polarization device: $$^{3}$$He Spin Filter. Since this device is often used for the fundamental physics region, it is important to cooperate with scientists in this region for further development. In order to explain the matter-dominated universe, a time reversal violation is necessary and searches for new physics are conducted in the world. The T-violation search experiment using a polarized neutron beam is planned at J-PARC. A large $$^{3}$$He spin filter is needed to polarize epi-thermal neutron for the experiment and is developed in JAEA. Recently, user's experiments for the T-violation search using $$^{3}$$He spin filter were conducted. The current status of the development of the $$^{3}$$He spin filter and feature plan will be presented.

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