Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 3; Neutron devices and computational and sample environments

Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.

Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09

https://doi.org/10.3390/qubs1020010

Neutron devices such as neutron detectors, optical devices including supermirror devices and He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.

Temperature control system for laser heating; Application for minute asteroidal materials

Osawa, Takahito; Kobayashi, Mikihiko*; Konno, Takeshi*; Egashira, Mitsuru*; Okazaki, Ryuji*; Miura, Yayoi*; Nagao, Keisuke*

Measurement, 50, p.229 - 235, 2014/04

https://doi.org/10.1016/j.measurement.2013.12.044

A temperature control system for a laser heating has been developed to extract noble gases from minute material samples recovered from the asteroid Itokawa by the Hayabusa spacecraft. An ultra-fine thermocouple was produced from 3% Re-W and 26% Re-W wires 25 m in diameter, and its electromotive force was calibrated. A temperature control program was originally produced using LabVIEW 2011 in which proportional-integral-derivative (PID) control was not adopted as an algorithm of the program. The program controlled the temperature of the tiny samples appropriately. The average temperature during heating was slightly lower than the setting temperature and the standard deviation and the maximum overshoot were lower than 2.5% and 6.0% of the setting temperature, respectively. The performance of the temperature control system is high enough to conduct the stepwise heating experiment for minute extraterrestrial material samples.

Construction of a newly designed small-size mass spectrometer for helium isotope analysis; Toward the continuous monitoring of He/He ratios in natural fluids

Bajo, Kenichi*; Sumino, Hirochika*; Toyoda, Michisato*; Okazaki, Ryuji*; Osawa, Takahito; Ishihara, Morio*; Katakuse, Itsuo*; Notsu, Kenji*; Igarashi, Joji*; Nagao, Keisuke*

Mass Spectrometry (Internet), 1(2), p.A0009_1 - A0009_10, 2012/11

https://doi.org/10.5702/massspectrometry.A0009

The construction of a small-size, magnetic sector, single focusing mass spectrometer (He-MS) for the continuous, on-site monitoring of the He isotope ratio (He/He) is described. The instrument is capable of measuring He/Ne ratios dissolved in several different types of natural fluids of geochemical interest, such as groundwater and gas from hot springs, volcanoes and gas well fields. Ion optics of the He-MS was designed by using the ion trajectory simulation program TRIO so as to measure He and He simultaneously with a double collector system under mass resolution power of 500. Presently attained specifications of the He-MS are; (1) mass resolving power of ca. 490, enough to separate He from interfering ions, HD and H, (2) ultra-high vacuum condition, and (3) high sensitivity enough to detect He amount 3000000 atoms).

Anomalous low-field diamagnetic response in ultraclean URuSi superconductor

Okazaki, Ryuji*; Shimozawa, Masaaki*; Shishido, Hiroaki*; Konczykowski, M.*; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Onuki, Yoshichika; Yanase, Yoichi*; Shibauchi, Takasada*; et al.

Journal of Physics; Conference Series, 273, p.012081_1 - 012081_4, 2011/02

https://doi.org/10.1088/1742-6596/273/1/012081

Lower critical fields and the anisotropy in PrFeAsO single crystals

Okazaki, Ryuji*; Konczykowski, M.*; Van der Beek, C. J.*; Kato, Tomonari*; Hashimoto, Kenichiro*; Shimozawa, Masaaki*; Shishido, Hiroaki*; Yamashita, Minoru*; Ishikado, Motoyuki; Kito, Hijiri*; et al.

Physica C, 470(Suppl.1), p.S485 - S486, 2010/12

https://doi.org/10.1016/j.physc.2009.12.041

We report the lower critical fields measurements on Fe-based oxipnictide PrFeAsO single crystals for and -planes. To avoid the difficulty of determinations due to the flux pinning, we developed a novel method using a miniature hall-sensor array which can evaluate the local magnetic induction ai each sensor position. The hall sensor which is placed on the edge of the crystal clearly resolves the first flux penetration from the Meissner state. The temperature dependence of for is well scaled by the in-plane penetration depth and is consistent with a full-gap superconducting state. The anistropy of at low temperatures is estimated to be 3, which is much smaller than of . This indicates the multiband superconductivity, in which the active bands for superconductivity are more two-dimensional.

Exotic superconducting state embedded in the hidden order state of URuSi

Matsuda, Yuji*; Okazaki, Ryuji*; Kasahara, Yuichi*; Shishido, Hiroaki*; Shibauchi, Takasada*; Haga, Yoshinori; Matsuda, Tatsuma; Onuki, Yoshichika

Physica C, 470(20), p.1013 - 1017, 2010/11

https://doi.org/10.1016/j.physc.2010.05.023

Flux pinning in PrFeAsO and NdFeAsOF superconducting crystals

Van der Beek, C. J.*; Rizza, G.*; Konczykowski, M.*; Fertey, P.*; Monnet, I.*; Klein, T.*; Okazaki, Ryuji*; Ishikado, Motoyuki; Kito, Hijiri*; Iyo, Akira*; et al.

Physical Review B, 81(17), p.174517_1 - 174517_11, 2010/05

https://doi.org/10.1103/PhysRevB.81.174517

Local magnetic measurements are used to quantitatively characterize heterogeneity and flux line pinning in PrFeAsO and NdFeAs(O,F)superconducting single crystals. In spite of spatial fluctuations of the critical current density on the macroscopic scale, it is shown that the major contribution comes from collective pinning of vortex lines by microscopic defects by the mean-free path fluctuation mechanism. The defect density extracted from experiment corresponds to the dopant atom density, which means that dopant atoms play an important role both in vortex pinning and in quasi-particle scattering.

Flux line lattice melting and the formation of a coherent quasiparticle bloch state in the ultraclean URuSi superconductor

Okazaki, Ryuji*; Kasahara, Yuichi*; Shishido, Hiroaki*; Konczykowski, M.*; Behnia, K.*; Haga, Yoshinori; Matsuda, Tatsuma; Onuki, Yoshichika; Shibauchi, Takasada*; Matsuda, Yuji*

Physical Review Letters, 100(3), p.037004_1 - 037004_4, 2008/01

https://doi.org/10.1103/PhysRevLett.100.037004

Muonic X-ray analysis for Ryugu samples

Osawa, Takahito; Ninomiya, Kazuhiko*; Nakamura, Tomoki*; Takahashi, Tadayuki*; Terada, Kentaro*; Yurimoto, Hisayoshi*; Noguchi, Takaaki*; Okazaki, Ryuji*; Yabuta, Hikaru*; Naraoka, Hiroshi*; et al.

no journal, , 

I report on the muonic X-ray analysis experiment conducted at J-PARC from 2020 to 2021, in which the analytical method was significantly developed through four preliminary experiments and successfully analyzed samples from the asteroid Ryugyu in July 2021. The experimental process is described from a radiochemical point of view.