Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

https://doi.org/10.1038/s41550-020-01271-2

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Detection of a gas region in a human body across a therapeutic carbon beam by measuring low-energy photons

Yamaguchi, Mitsutaka; Nagao, Yuto; Kawachi, Naoki; Sato, Takahiro; Fujimaki, Shu; Kamiya, Tomihiro; Torikai, Kota*; Shimada, Hirofumi*; Sugai, Hiroyuki*; Sakai, Makoto*; et al.

International Journal of PIXE, 26(1&2), p.61 - 72, 2016/00

https://doi.org/10.1142/S0129083516500078

no abstracts in English

Time resolution of beam phase distribution measurement system for the JAEA AVF cyclotron

Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1179 - 1181, 2014/10

http://www.pasj.jp/web_publish/pasj2014/proceedings/PDF/SUP0/SUP070.pdf

no abstracts in English

Geometric analysis of phase bunching in the central region of cyclotron

Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro

Nuclear Instruments and Methods in Physics Research A, 715, p.126 - 131, 2013/07

https://doi.org/10.1016/j.nima.2013.03.033

An optimum condition for realizing phase bunching in the central region of a cyclotron was quantitatively clarified by a simplified geometric trajectory analysis of charged particles from the first to the second acceleration gap. The phase-bunching performance was evaluated for a general case of a cyclotron. The phase difference of incident particles at the second acceleration gap depends on the combination of four parameters: the acceleration harmonic number , the span angle of the dee electrode, the span angle from the first to the second acceleration gap, the ratio of the peak acceleration voltage between the cyclotron and ion source. Optimum values of for phase bunching were limited by the relationship between and , which is 90/+/2 180/+/2, and sin 0. The phase difference with respect to the reference particle at the second acceleration gap is minimized for voltage-ratios between two and four for an initial phase difference within 40 RF degrees. Although the slope of the first acceleration gap contributes to the RF phase at which the particles reach the second acceleration gap, phase bunching was not affected. An orbit simulation of the JAEA AVF cyclotron verifies the evaluation based on geometric analysis.

A New method for monitoring beam range by measuring low energy photons

Yamaguchi, Mitsutaka; Torikai, Kota*; Kawachi, Naoki; Shimada, Hirofumi*; Sato, Takahiro; Nagao, Yuto; Fujimaki, Shu; Kokubun, Motohide*; Watanabe, Shin*; Takahashi, Tadayuki*; et al.

Proceedings of 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 2 Pages, 2013/00

https://doi.org/10.1109/NSSMIC.2013.6829328

Beam range estimation by measuring bremsstrahlung

Yamaguchi, Mitsutaka; Torikai, Kota*; Kawachi, Naoki; Shimada, Hirofumi*; Sato, Takahiro; Nagao, Yuto; Fujimaki, Shu; Kokubun, Motohide*; Watanabe, Shin*; Takahashi, Tadayuki*; et al.

Physics in Medicine & Biology, 57(10), p.2843 - 2856, 2012/05

https://doi.org/10.1088/0031-9155/57/10/2843

Analysis on the co-localization of asbestos bodies and Fas or CD163 expression in asbestos lung tissue by in-air micro-PIXE

Dobashi, Kunio*; Shimizu, Yasuo*; Matsuzaki, Shinichi*; Nagamine, Takeaki*; Sato, Takahiro; Okubo, Takeru; Yokoyama, Akihito; Ishii, Yasuyuki; Kamiya, Tomihiro; Arakawa, Kazuo*; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 87, 2012/01

https://doi.org/10.11484/jaea-review-2011-043

Realization of a phase bunching effect for minimization of beam phase width in a central region of an AVF cyclotron

Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Okumura, Susumu; Kashiwagi, Hirotsugu; Nara, Takayuki; Ishibori, Ikuo; Yoshida, Kenichi; Yokota, Wataru; Nakamura, Yoshiteru*; et al.

Nuclear Instruments and Methods in Physics Research A, 636(1), p.41 - 47, 2011/04

https://doi.org/10.1016/j.nima.2011.01.174

A phase bunching effect has been achieved for the first time using a rising slope of the dee voltage waveform produced at the first acceleration gap between the RF shielding cover of the inflector and the puller in the new central region of the JAEA AVF cyclotron. The feasibility of the phase bunching effect in the central region for a two-dee system with a span angle of 86 in three acceleration harmonic modes was assessed by a simple geometrical analysis of particle trajectories and a three-dimensional beam orbit simulation. The simulation indicated that the initial beam phase width of 40 RF degrees is compressed to 11 RF degrees in the second harmonic mode. A phase width of 1.5 RF degrees FWHM for a 260 MeV Ne beam accelerated in the second harmonic mode was reduced by the bunching effect, compared with the beam phase width of 7.3 RF degrees FWHM in the same harmonic mode for a 10 MeV H beam accelerated in the original central region.

Quantitative analysis of cisplatin sensitivity of human esophageal squamous cancer cell lines using in-air micro-PIXE

Tanaka, Naritake*; Kimura, Hitoshi*; Faried, A.*; Sakai, Makoto*; Sano, Takaaki*; Inose, Takanori*; Soda, Makoto*; Okada, Koji*; Nakajima, Masanobu*; Miyazaki, Tatsuya*; et al.

Cancer Science, 101(6), p.1487 - 1492, 2010/06

https://doi.org/10.1111/j.1349-7006.2010.01542.x

We examined the intracellular localization of cisplatin, a key chemotherapeutic agent, in esophageal cancer cell lines and determined their sensitivity to cisplatin using in-air micro-PIXE. Two human esophageal squamous cell carcinoma (ESCC) cell lines, TE-2 and TE-13, were examined for their response to cisplatin using MTT assay, flow cytometry and DNA fragmentation assays. Real-time reverse transcription-polymerase chain reaction was also used to evaluate the mRNA expression of multidrug resistance protein 2 (MRP2) in both cell lines. Platinum localizations of intracellular and intranuclear were measured using in-air micro-PIXE. TE-2 cells were more sensitive to cisplatin than TE-13 cells. The results of this study suggest that in-air micro-PIXE could be a useful quantitative method for evaluating the cisplatin sensitivity of individual cells. Finally, we speculate that MRP2 in the cell membrane may play an important role in regulating cisplatin sensitivity of ESCC cells.

Single-turn extraction from a K110 AVF cyclotron by flat-top acceleration

Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; Yoshida, Kenichi; Yokota, Wataru; Nakamura, Yoshiteru*; Arakawa, Kazuo; et al.

Review of Scientific Instruments, 80(3), p.033302_1 - 033302_9, 2009/03

https://doi.org/10.1063/1.3093810

Single-turn extraction from the JAEA AVF cyclotron with a K number of 110 using a flat-top (FT) acceleration system has been achieved to reduce the energy spread of an ion beam for microbeam formation with energy up to hundreds of MeV and to increase extraction efficiency from the cyclotron. In order to generate an FT waveform voltage using the fifth-harmonic frequency on a dee electrode, an FT resonator was designed using MAFIA code to achieve downsizing and low power consumption. The FT resonator, coupled to the main resonator through a coupling capacitor, covered the full range of the fifth harmonic frequency from 55 to 110 MHz. Various ion beams, accelerated using different acceleration harmonic mode of h = 1 and 2, such as 220 MeV C (h = 2), 260 MeV Ne (h = 2), and 45 MeV H (h = 1) were developed by FT acceleration. A clear turn separation of the beam bunches was successfully observed at the extraction region of the large-scale AVF cyclotron with number of revolutions greater than 200. As a result, high extraction efficiency (over 95%) from the cyclotron was achieved. Single-turn extraction was confirmed by counting the number of beam bunches out of the cyclotron for an injected beam pulsed by a beam chopping system in the injection line. The energy spread of the 260 MeV Ne beam was measured using an analyzing magnet and we verified a reduction of the energy spread from E/E = 0.1% to 0.05% by single-turn extraction.