Present status of TIARA at JAEA

Yuyama, Takahiro; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Ishizaka, Tomohisa; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Miyawaki, Nobumasa; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.302 - 304, 2015/09

http://www.pasj.jp/web_publish/pasj2015/proceedings/PDF/FSP0/FSP010.pdf

no abstracts in English

The Nebula Winter; The United view of the snowball Earth, mass extinctions, and explosive evolution in the late Neoproterozoic and Cambrian periods

Kataoka, Ryuho*; Ebisuzaki, Toshikazu*; Miyahara, Hiroko*; Nimura, Tokuhiro*; Tomida, Takayuki*; Sato, Tatsuhiko; Maruyama, Shigenori*

Gondwana Research, 25(3), p.1153 - 1163, 2014/04

https://doi.org/10.1016/j.gr.2013.05.003

We propose the Nebula Winter model to explain catastrophic events of the earth, such as mass extinctions and snowball earth events. Encounters with nebulae, such as supernova remnants and dark clouds in the galaxy, can lead to a catastrophic environmental change on the Earth through the destruction of the ozone layer and climate forcing by enhanced fluxes of cosmic rays and cosmic dust particles.

Current status of electrostatic accelerators at TIARA

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Kitano, Toshihiko*; Takayama, Terumitsu*; Orimo, Takao*; Kanai, Shinji*; Aoki, Yuki*; et al.

Dai-26-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.79 - 81, 2013/07

Three electrostatic accelerators at TIARA were operated on schedule in fiscal year 2012 except changing its schedule by cancellations of users. The yearly operation time of the 3MV tandem accelerator, the 400 kV ion implanter and the 3 MV single-ended accelerator were in the same levels as the ordinary one, whose operation time totaled to 2,073, 1,847 and 2,389 hours, respectively. The tandem accelerator had no trouble, whereas the ion implanter and the single-ended accelerator stopped by any troubles for one day and four days, respectively. The ion implanter generated molecular ion beam of helium hydride by using the Freeman type ion source, because of the request from the user. As a result, its intensity of beam was 50 nA at 200 kV.

Operation of electrostatic accelerators at TIARA

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Nara, Takayuki; Kitano, Toshihiko*; et al.

Dai-7-Kai Takasaki Oyo Kenkyu Shimpojiumu Yoshishu, P. 119, 2012/10

The three electrostatic accelerators at TIARA had no damage when the Tohoku earthquake happened on March 11, 2011. But, they could not be operated until end of April, due to the influence of planned power outage and keep out into the controlled area for radiation. These accelerators additionally operated on Saturday for twelve days in order to compensate for the lost experiment time. Therefore, the yearly operation time had kept the same level as the ordinary one. The tandem accelerator has stopped leakage of the SF gas from the base flange on the tank by the Viton gasket of rectangular cross section at the new type.

Status of TIARA facility

Yamada, Keisuke; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; et al.

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08

http://www.pasj.jp/web_publish/pasj8/proceedings/poster/MOPS012.pdf

no abstracts in English

Quick change of ion species of heavy-ion microbeam by cocktail beam acceleration technique with the JAEA AVF cyclotron

Kurashima, Satoshi; Yoshida, Kenichi; Oikawa, Masakazu*; Sato, Takahiro; Miyawaki, Nobumasa; Yuyama, Takahiro; Okumura, Susumu; Kashiwagi, Hirotsugu; Ishibori, Ikuo; Nara, Takayuki; et al.

Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2024 - 2027, 2009/06

https://doi.org/10.1016/j.nimb.2009.03.083

A heavy-ion microbeam with energy of hundreds of MeV is utilized for research in biotechnology and materials science at the JAEA AVF cyclotron facility. Beam users need microbeams providing a wide range of linear energy transfer (LET). In order to vary LET widely, we have to change the ion species and/or energy. A cocktail beam acceleration technique is frequently used to change the ion species quickly. Ion species and energy can be changed by slightly shifting the acceleration frequency. The cocktail acceleration technique has been applied to microbeam production for quick change of ion species of a microbeam. As a result, we have succeeded to reduce considerably microbeam changing time to within 30 minutes between a 260 MeV Ne and a 520 MeV Ar. No deterioration of a microbeam spot size has been confirmed using a secondary electron microscope image of a copper mesh.

Status of accelerators and technical development at TIARA

Yokota, Wataru; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; et al.

Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.22 - 24, 2008/08

no abstracts in English

Developments at JAEA AVF cyclotron facility for heavy-ion microbeam

Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Ishibori, Ikuo; Yoshida, Kenichi; Sato, Takahiro; Kashiwagi, Hirotsugu; Yuri, Yosuke; Agematsu, Takashi; Nara, Takayuki; et al.

Proceedings of 18th International Conference on Cyclotrons and Their Applications (CYCLOTRONS 2007), p.131 - 133, 2007/00

We have been improving the beam quality of the JAEA (Japan Atomic Energy Agency) AVF cyclotron to form a several-hundred-MeV heavy-ion microbeam by a magnetic focusing lens. An energy spread of the order of 10, obtained by ordinary acceleration using a fundamental dee voltage, makes it difficult to focus an ion beam to a spot size of 1 m in diameter with focusing lens because of the chromatic aberration. A flat-top acceleration system using the fifth-harmonic frequency of the acceleration frequency was installed in the cyclotron in order to reduce to the order of 10. In addition, developments of a new center region, an energy spread measurement system using an analyzing magnet and a high performance beam buncher are in progress. The energy spread of the 260 MeV Ne beam has been reduced to 0.05% by the flat-top acceleration, and the microbeam with a spot size of approximately 1 m has been successfully formed.

Power supply system for JAERI AVF cyclotron

Nakamura, Yoshiteru; Yokota, Wataru; Okumura, Susumu; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Arakawa, Kazuo; Hoshika, Keizo*; *

JAERI-M 94-054, 61 Pages, 1994/03

JAERI-M-94-054.pdf:2.75MB

no abstracts in English

Millimeter wave amplification in a free electron laser with a focusing wiggler

Sakamoto, Keishi; *; Kawasaki, S.*; Kishimoto, Yasuaki; Musyoki, S.*; *; *; Ishizuka, H.*; *;

Journal of Applied Physics, 75(1), p.36 - 42, 1994/01

https://doi.org/10.1063/1.355861

no abstracts in English