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.

Synchrotron oscillation relevant to transverse laser cooling in S-LSR

Jimbo, Koichi*; Soda, Hikaru*; Nakao, Masao*; Yuri, Yosuke; Tongu, Hiromu*; Noda, Akira*

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1057 - 1059, 2014/06

http://www.pasj.jp/web_publish/pasj10/proceedings/PDF/SUP0/SUP068.pdf

Simulation study on transverse laser cooling and crystallization of heavy-ion beams at the cooler storage ring S-LSR

Yuri, Yosuke; Osaki, Kazuya*; Okamoto, Hiromi*; He, Z.*; Soda, Hikaru*; Noda, Akira*; Nakao, Masao*; Tongu, Hiromu*; Jimbo, Koichi*

Proceedings of Workshop on Beam Cooling and Related Topics (COOL '13) (Internet), p.162 - 165, 2013/11

http://accelconf.web.cern.ch/AccelConf/COOL2013/papers/tham1ha03.pdf

Parameter optimization for multi-dimensional laser cooling of an ion beam in the storage ring S-LSR

He, Z.*; Wei, J.*; Osaki, Kazuya*; Okamoto, Hiromi*; Noda, Akira*; Nakao, Masao*; Soda, Hikaru*; Yuri, Yosuke; Jimbo, Koichi*

Proceedings of 25th North American Particle Accelerator Conference (NA-PAC '13) (Internet), p.1298 - 1300, 2013/09

http://accelconf.web.cern.ch/AccelConf/PAC2013/papers/thpho01.pdf

Efficiency enhancement of indirect transverse laser cooling with synchro-betatron resonant coupling by suppression of beam intensity

Soda, Hikaru*; Nakao, Masao*; Tongu, Hiromu*; Jimbo, Koichi*; Osaki, Kazuya*; Okamoto, Hiromi*; Yuri, Yosuke; He, Z.*; Grieser, M.*; Noda, Akira*

Japanese Journal of Applied Physics, 52(3), p.030202_1 - 030202_4, 2013/03

https://doi.org/10.7567/JJAP.52.030202

Measurement of transverse laser cooling effect using scrapers

Soda, Hikaru*; Nakao, Masao*; Tongu, Hiromu*; Noda, Akira*; Jimbo, Koichi*; Osaki, Kazuya*; Okamoto, Hiromi*; Yuri, Yosuke; Grieser, M.*; He, Z.*

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.388 - 390, 2012/08

http://www.pasj.jp/web_publish/pasj9/proceedings/PDF/WEPS/WEPS016.pdf

no abstracts in English

Observation of 2-component bunched beam signal with laser cooling

Soda, Hikaru*; Nakao, Masao*; Noda, Akira*; Tongu, Hiromu*; Ito, Kiyokazu*; Okamoto, Hiromi*; Yuri, Yosuke; Jimbo, Koichi*; Grieser, M.*; He, Z.*

Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.397 - 399, 2012/05

http://accelconf.web.cern.ch/accelconf/IPAC2012/papers/moppd013.pdf

Prompt in-line diagnosis of single bunch transverse profiles and energy spectra for laser-accelerated ions

Sakaki, Hironao; Nishiuchi, Mamiko; Hori, Toshihiko; Bolton, P.; Yogo, Akifumi; Katagiri, Masaki*; Ogura, Koichi; Sagisaka, Akito; Pirozhkov, A. S.; Orimo, Satoshi; et al.

Applied Physics Express, 3(12), p.126401_1 - 126401_3, 2010/11

https://doi.org/10.1143/APEX.3.126401

Many applications of laser-accelerated ions will require beamlines with diagnostic capability for validating simulations and machine performance at the single bunch level as well as for the development of controls to optimize machine performance. We demonstrated prompt, in-line, single bunch transverse profile and energy spectrum detection using a thin luminescent diagnostic and scintillator-based time-of-flight spectrometer simultaneously. The Monte Carlo code, particle and heavy ion transport code systems (PHITS) simulation is shown to be reasonably predictive at low proton energy for the observed transverse profiles measured by the thin luminescent monitor and also for single bunch energy spectra measured by time-of-flight spectrometry.

Measured and simulated transport of 1.9 MeV laser-accelerated proton bunches through an integrated test beam line at 1 Hz

Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.

Physical Review Special Topics; Accelerators and Beams, 13(7), p.071304_1 - 071304_7, 2010/07

https://doi.org/10.1103/PhysRevSTAB.13.071304

A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotationcavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weakproton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.

Designing integrated laser-driven ion accelerator systems for hadron therapy at PMRC (Photo Medical Research Center)

Sakaki, Hironao; Hori, Toshihiko; Nishiuchi, Mamiko; Bolton, P.; Daido, Hiroyuki; Kawanishi, Shunichi; Sutherland, K.*; Soda, Hikaru*; Noda, Akira*; Iseki, Yasushi*; et al.

Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.1309 - 1311, 2009/05

The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven hadrons acceleration. The Photo Medical Research Center (PMRC) of JAEA was recently established to address the challenge of laser-driven ion accelerator development for hadron beam cancer therapy. PMRC considers conceptual designs of such a therapeutic instrument based on the current state in the laser-driven acceleration. We describe a conceptual gantry device that is designed by the general-purpose ion accelerator design code, PARMILA.