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Yokota, Wataru; Yuri, Yosuke; Watanabe, Shinichi*; Oshiro, Yukimitsu*; Kubono, Shigeru*
JAEA-Technology 2016-005, 21 Pages, 2016/03
JAEA-Technology-2016-005.pdf:2.24MB
The Center of Nuclear Science (CNS) of Tokyo University conducts the research on nuclear physics using CNS Radio-Isotope Beam Separator (CRIB) installed at the RIKEN AVF cyclotron. Takasaki Advanced Radiation Research Institute, JAEA has an AVF cyclotron of similar scale and is developing a technology to form a large-area uniform beam by an octupole magnetic field for the research on materials science. They carried out an R&D to increase the cyclotron beam intensity at a target under joint research. The nonlinear beam optics was designed to form a usual cyclotron beam having a large transverse tail into a small-sized tailless distribution so that the beam passes the gas target orifice (6 mm in diameter) of CRIB without a loss. As a result of particle tracking simulations based on the measured beam emittance, it has been found that an octupole magnetic field is effective in tail-folding and a 10-mm-diameter beam can be formed with two octupole magnets added in the present beam line. It has been also found that additional magnets need to be installed and the beam emittance should be reduced for the objective beam size of 6 mm. Moreover, the objective may be attained if the beam path length and configuration of the magnetic lens system are freely chosen.
Yokoyama, Akihito; Kada, Wataru*; Sato, Takahiro; Koka, Masashi; Shimada, Keisuke*; Yokota, Yuya*; Miura, Kenta*; Hanaizumi, Osamu*
Nuclear Instruments and Methods in Physics Research B, 371, p.340 - 343, 2016/03
Times Cited Count：6 Percentile：49.29(Instruments & Instrumentation)no abstracts in English
Yokota, Wataru
JAEA-Review 2015-022, 200 Pages, 2016/02
JAEA-Review-2015-022.pdf:56.06MB
JAEA Takasaki annual report 2014 describes research and development activities performed from April 1, 2014 to March 31, 2015 mainly with Takasaki Ion Accelerators for Advanced Radiation Application (TIARA, four ion accelerators), and electron/
-ray irradiation facilities (an electron accelerator and three 
Co -ray irradiation facilities) at Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA Takasaki). These activities are classified into four research fields:(1)Space, Nuclear and Energy Engineering, (2) Environmental Conservation and Resource Exploitation, (3) Medical and Biotechnological Application, and (4) Advanced Materials, Analysis and Novel Technology. This annual report contains 162 reports consisting of 154 research papers and 8 status reports on operation/maintenance of the irradiation facilities described above, a list of publications, patents, related press-releases, television broadcasting, and the type of research collaborations as appendices.
Ono, Yutaka; Yokota, Wataru
Kasokuki, 12(4), p.189 - 192, 2016/01
Yokoyama, Akihito; Kada, Wataru*; Sato, Takahiro; Koka, Masashi; Yamamoto, Shunya; Kamiya, Tomihiro; Yokota, Wataru
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 168, 2015/03
no abstracts in English
Yokota, Wataru; Sato, Takahiro; Kamiya, Tomihiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Funayama, Tomoo; Sakashita, Tetsuya; et al.
JAEA-Technology 2014-018, 103 Pages, 2014/09
JAEA-Technology-2014-018.pdf:123.66MB
The world's first microbeam focusing technology for heavy ions of hundreds MeV accelerated by a cyclotron has been developed at the TIARA facility in the Takasaki Advanced Radiation Research Institute of the Japan Atomic Energy Agency. The technology enables us to form a microbeam of less than 1 
m in diameter and to shoot a specified point on a target by one ion (single-ion hit) with spatial accuracy of microbeam size. In the course of the development, a cyclotron technology to accelerate a small energy-spread beam of hundres MeV, which is necessary for focusing to 1 m, has been developed as well as a beam focusing apparatus, beam size measurement and so forth based on the several-MeV microbeam/single-ion hit system of the TIARA electrostatic accelerators. Applicability of the technologies was examined by actual use in irradiation experiment and the result were fed back to them. This paper reports the process and the results of the development over ten years.
Yokoyama, Akihito; Kada, Wataru*; Sato, Takahiro; Koka, Masashi; Yamamoto, Shunya; Kamiya, Tomihiro; Yokota, Wataru
Nuclear Instruments and Methods in Physics Research B, 332, p.334 - 336, 2014/08
Times Cited Count：1 Percentile：10.25(Instruments & Instrumentation)A system is developed for the real-time position detection of single-ions which hits a target with spatial accuracy about 1 m. The system combines highly luminescent, sensitive, scintillators with a high sensitivity luminescence detection system. The real-time detection system contains a Al
O
:Eu scintillator, Eu implanting into 
-AlO. A single-crystal scintillator has been selected since position resolution of emission for powdery scintillator is limited by a grain size, several micrometers for ZnS for example. When the material is irradiated with an electron or ion beam, the Eu is activated and strong luminescence occurs. The detection system includes an image intensifier tube and an electron multiplier CCD camera. The results show that our system can be sufficiently sensitive to detect the hit of a single-ion in real time through simple improvement in emission intensity of the scintillator.
Yokoyama, Akihito; Kada, Wataru*; Sato, Takahiro; Koka, Masashi; Yamamoto, Shunya; Kamiya, Tomihiro; Yokota, Wataru
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 164, 2014/03
no abstracts in English
Yokota, Wataru; Sato, Takahiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Koka, Masashi; Yokoyama, Akihito; Kada, Wataru*; et al.
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 160, 2014/03
no abstracts in English
Yoshida, Kenichi; Nara, Takayuki; Saito, Yuichi; Yokota, Wataru
Review of Scientific Instruments, 85(2), p.02A917_1 - 02A917_3, 2014/02
Times Cited Count：1 Percentile：5.77(Instruments & Instrumentation)Recent studies about ECRIS have revealed that not only the maximum magnetic field (B
) but also the minimum field(B
) has effect on the production ability. A superconducting ECRIS which can change the B distribution with plural solenoids shows that a flat distribution of B (flat B) gives better performance in highly charged ion production than classical B. Superconducting device of conduction cooling type is useful, because a Lq-helium system needs a large quantity of Lq-helium to be supplied at after every quench. However, many refrigerators are necessary to keep low temperature against the heat through the current leads of a number of coils to form flat-B. Therefore, we have designed a coil configuration which can adjust B and flat-B with the minimum lead number of four. The flat-B is formed by three central coils connected one another between the mirror coils. There is another pair of coils to adjust B of the injection side keeping flat B unchanged.
Yamada, Keisuke; Saito, Yuichi; Yokota, Wataru
Review of Scientific Instruments, 85(2), p.02A920_1 - 02A920_3, 2014/02
Times Cited Count：1 Percentile：5.77(Instruments & Instrumentation)Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Sato, Takahiro; Kamiya, Tomihiro; Fukuda, Mitsuhiro*; Yokota, Wataru
Nuclear Instruments and Methods in Physics Research B, 306, p.40 - 43, 2013/07
Times Cited Count：2 Percentile：19.73(Instruments & Instrumentation)no abstracts in English
Yokota, Wataru; Sato, Takahiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Koka, Masashi; Yokoyama, Akihito; Kada, Wataru; et al.
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 156, 2013/01
The fast single-ion hit system installed in the HX course of the TIARA cyclotron was continuously improved for higher quality of microbeam and single-ion hit. The paper reports the progress in three major subjects of (1) reduction of the miss hit in the single-ion-hit irradiation, (2) development of the real-time detection system of single-ion-hit position and (3) new microbeam development, and the impact of the Great East Japan Earthquake on the system.
Yokoyama, Akihito; Kada, Wataru; Sato, Takahiro; Koka, Masashi; Yamamoto, Shunya; Kamiya, Tomihiro; Yokota, Wataru
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 159, 2013/01
no abstracts in English
Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Yokota, Wataru; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 173, 2012/01
Three electrostatic accelerators of TIARA were operated smoothly in FY 2010, and all the planned experiments were carried out except those canceled by users or the impact of Great East Japan Earthquake on March 11, 2011. On the other hand, Saturday operation for experiments was carried out after October on the Global Nuclear-Human Resource Development Initiative. The yearly operation time of the tandem accelerator, the single-ended accelerator and the ion implanter amounted to 2116, 2367 and 1800 hours, respectively, which were similar to those of usual years. Regarding the single-ended accelerator, the generator in the high-voltage terminal failed and was replaced with new one. A switching magnet was installed for a new branch beam line of the ion implanter. As to the tandem accelerator, In ion was generated and accelerated at intensity of 500 nA.
Yokota, Wataru; Sato, Takahiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Koka, Masashi; Takano, Katsuyoshi*; Yokoyama, Akihito; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 159, 2012/01
The development of the fast single-ion hit system was continued from last year in order to improve the quality of microbeam and single-ion hit at the TIARA cyclotron of the Japan Atomic Energy Agency. The major subjects were reduction of miss hit, no hit on the targeted point by any ions in the single-ion-hit irradiation, and development of a real-time detection system of single-ion hit. A new microbeam of 400 MeV-Fe with a spot diameter of about 4 m was also developed and supplied to an experiment.
Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yuri, Yosuke; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 172, 2012/01
no abstracts in English
Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Okumura, Susumu; Kurashima, Satoshi; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Ishibori, Ikuo; Nara, Takayuki; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 157, 2012/01
no abstracts in English
Yokoyama, Akihito; Kada, Wataru; Sato, Takahiro; Koka, Masashi; Yamamoto, Shunya; Kamiya, Tomihiro; Yokota, Wataru
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 160, 2012/01
no abstracts in English
Kurashima, Satoshi; Taguchi, Mitsumasa; Ishibori, Ikuo; Nara, Takayuki; Yokota, Wataru
Proceedings of 19th International Conference on Cyclotrons and their Applications (CYCLOTRONS 2010), p.247 - 249, 2011/12
