Makii, Hiroyuki; Ota, Shuya*; Ishii, Tetsuro; Wakabayashi, Yasuo*; Furutaka, Kazuyoshi; Nishio, Katsuhisa; Nishinaka, Ichiro; Chiba, Satoshi; Igashira, Masayuki*; Czeszumska, A.*
Nuclear Instruments and Methods in Physics Research A, 797, p.83 - 93, 2015/10
We have installed new experimental apparatus to measure rays from highly excited states populated by the multi-nucleon transfer reactions with heavy-ion projectiles to determine the () cross sections by means of the surrogate reaction method. Apparatus consists of two anti-Compton LaBr(Ce) spectrometers to measure the rays and a Si - detector system to detect outgoing projectile-like particles. Reactions of 153-MeV O beams with Gd and Gd targets were used to study the performance of apparatus. By using the LaBr(Ce) scintillators with relatively large volume (101.6 mm in diameter and 127 mm in length), we have successfully measured rays from the compound nuclei, which have excitation energy above neutron separation energy, populated by Gd(O, O)Gd and Gd(O, O)Gd two-neutron transfer reactions. The present study has demonstrated high capability of apparatus to measure the de-excitation rays in the compound nuclei produced by the multi-nucleon transfer reactions for determination of the () cross sections by using the surrogate reaction method.
Ishii, Tetsuro; Osa, Akihiko; Nishio, Katsuhisa; Asai, Masato; Ishikawa, Norito; Matsuda, Makoto
JAEA-Review 2014-002, 238 Pages, 2014/08
The facility of the JAEA-Tokai tandem accelerator has been contributing toward advancing heavy ion science researches in the fields of nuclear physics, nuclear chemistry, production of RI for nuclear medicine, atomic physics, radiation effects, and so on. Due to the 2011 off the Pacific coast of Tohoku Earthquake and all that, situation revolving around the JAEA-Tokai tandem accelerator was greatly-changed. For active discussions of this situation among scientists in the different fields, the workshop "Heavy Ion Science in Tandem Energy Region" was held although there has been no such workshop for many years. The users of the JAEA-Tokai tandem accelerators made presentations of their research achievements in the last few years and reviewed the recent research trend of each fields. This workshop was held at Research building No.1 in Nuclear Research Institute on July 2nd and 3rd in 2013, having 20 oral presentations and 28 posters, and successfully carried out with as many as 60 participants and a lot of serious discussions. This review is the collection of slides of oral presentations.
Chiba, Satoshi; Nishio, Katsuhisa; Makii, Hiroyuki; Aritomo, Yoshihiro*; Nishinaka, Ichiro; Ishii, Tetsuro; Tsukada, Kazuaki; Asai, Masato; Furutaka, Kazuyoshi; Hashimoto, Shintaro; et al.
Nuclear Data Sheets, 119, p.229 - 232, 2014/05
Makii, Hiroyuki; Ota, Shuya*; Ishii, Tetsuro; Nishio, Katsuhisa; Nishinaka, Ichiro; Furutaka, Kazuyoshi; Wakabayashi, Yasuo*; Chiba, Satoshi*; Igashira, Masayuki*
Nuclear Data Sheets, 119, p.361 - 364, 2014/05
Anti-Compton LaBr(Ce) spectrometers have been installed at JAEA-Tokai tandem accelerator facility in order to measure the rays from the highly excited states produced by surrogate reactions. Each spectrometer consists of a central LaBr(Ce) detector with a diameter of 10.2 cm and a length of 12.7 cm, and an annular BGO detector with a thickness of 2.5 cm and a length of 25.4 cm. In this contribution, we will present the results of performance test using the standard ray source and high-energy rays from the Al(p,)Si reaction, and a measurement plan for (n,) cross sections using a surrogate reaction at JAEA-Tokai tandem accelerator facility.
Asai, Masato; Tsukada, Kazuaki; Sakama, Minoru*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ishii, Yasuo; Toyoshima, Atsushi; Ishii, Tetsuro; Nishinaka, Ichiro; Nagame, Yuichiro; et al.
Physical Review C, 87(1), p.014332_1 - 014332_6, 2013/01
The spin-parity and neutron configuration of the ground state of No have been identified through -decay spectroscopy. The No is the nucleus with the largest neutron number whose spin-parities and single-particle configurations have ever been identified. The neutron 9/2 configuration was assigned to the ground state of No as well as to the 231.4 keV level in Fm. This allowed us to establish energy spacings and order of the neutron single-particle orbitals in such heaviest nuclear region. The appearance of the 9/2 ground state at =157 implies that the order of the neutron orbitals between the =152 and 162 deformed shell gaps should change considerably with increasing neutron number.
Hirayama, Yoshikazu*; Mihara, Mototsugu*; Watanabe, Yutaka*; Jeong, S. C.*; Miyatake, Hiroari*; Momota, Sadao*; Hashimoto, Takashi*; Imai, Nobuaki*; Matsuta, Kensaku*; Ishiyama, Hironobu*; et al.
European Physical Journal A, 48(5), p.54_1 - 54_10, 2012/05
Matsuda, Makoto; Osa, Akihiko; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; et al.
Dai-24-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.51 - 54, 2011/07
no abstracts in English
Asai, Masato; Tsukada, Kazuaki; Haba, Hiromitsu*; Ishii, Yasuo; Ichikawa, Takatoshi*; Toyoshima, Atsushi; Ishii, Tetsuro; Nagame, Yuichiro; Nishinaka, Ichiro; Kojima, Yasuaki*; et al.
Physical Review C, 83(1), p.014315_1 - 014315_12, 2011/01
Excited states in Fm populated via the decay of No are studied in detail through - coincidence and fine structure measurements. Spin-parities and neutron configurations of the excited states in Fm as well as the ground state of No are definitely identified on the basis of deduced internal conversion coefficients, lifetimes of transitions, rotational-band energies built on one-quasiparticle states, and hindrance factors of transitions. It is found that the excitation energy of the 1/2 state in =151 isotones increases with the atomic number, especially at 100, while that of the 1/2 state decreases at =100. Energy systematics of the one-quasiparticle states in the =151 isotones are discussed in terms of the evolution of nuclear deformation involving the hexadecapole and hexacontatetrapole deformations.
Ishizaki, Nobuhiro; Ishii, Tetsuro; Abe, Shinichi; Hanashima, Susumu; Osa, Akihiko; Tayama, Hidekazu; Matsuda, Makoto; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; et al.
Dai-23-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.13 - 16, 2010/11
no abstracts in English
Takahashi, Ryuta; Ishii, Tetsuro; Asai, Masato; Nagae, Daisuke*; Makii, Hiroyuki; Tsukada, Kazuaki; Toyoshima, Atsushi; Ishii, Yasuo; Matsuda, Makoto; Makishima, Akiyasu*; et al.
Physical Review C, 81(5), p.057303_1 - 057303_4, 2010/05
The ground-state bands of Cf have been established up to 10, 12, and 10 states, respectively, by in-beam -ray spectroscopy using neutron-transfer reactions with a O beam and a highly radioactive Cf target. The deexcitation rays in Cf were identified by taking coincidences with outgoing particles of O measured with Si - detectors, and by selecting their kinetic energies. This is the first in-beam -ray spectroscopy for Cf isotopes.
Nagae, Daisuke*; Ishii, Tetsuro; Takahashi, Ryuta*; Asai, Masato; Makii, Hiroyuki; Osa, Akihiko; Sato, Tetsuya; Ichikawa, Shinichi; Shimizu, Yoshifumi*; Shoji, Takuya*
AIP Conference Proceedings 1224, p.156 - 160, 2010/04
Matsuda, Makoto; Ishii, Tetsuro; Tsukihashi, Yoshihiro; Hanashima, Susumu; Abe, Shinichi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; et al.
Dai-22-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.10 - 14, 2010/01
no abstracts in English
Ishii, Tetsuro; Matsuda, Makoto; Kabumoto, Hiroshi; Osa, Akihiko
AIP Conference Proceedings 1120 (Internet), p.235 - 240, 2009/05
Recent activities in the tandem accelerator facility were reported. The terminal voltage of 19.1 MV was achieved by replacing acceleration tubes with new ones cleaned by high-pressure water-jet method. We have also installed an ECR source on the terminal, which makes it possible to accelerate high-current noble-gas beams. By these developments together with a unique target room allowed to use radioactive and nuclear fuel targets, experiments on nuclear chemistry, nuclear physics and radiation effects of nuclear fuels have been evolved. Using the superconducting booster, nuclear reaction experiments, frequently changing incident beam energies within a short period of time, were carried out. We have succeeded in accelerating short-lived radioactivities of Li, In and Ba with the radioactive nuclear beam accelerator, TRIAC, and have performed experiments on diffusion of Li in ionic conductors and on nuclear astrophysics.
Ishii, Tetsuro; Osa, Akihiko; Okayasu, Satoru; Ishikawa, Norito; Nishio, Katsuhisa; Tsukada, Kazuaki; Ishiyama, Hironobu*
JAEA-Review 2009-006, 286 Pages, 2009/04
Workshop of the JAEA-Tokai tandem accelerator was held every two years. As a memorial of 100,000-hour operation of the tandem accelerator, we reviewed developments and experiments carried out so far, together with discussion of experiments in progress and in future. As previous series of workshops, we offered an opportunity to have active discussion among scientists of different fields including accelerator, nuclear physics, nuclear chemistry, radiation effects, atomic physics and so on, aiming at extending facility and research interactively. As a memorial lecture, Dr. Akira Tonomura, fellow of Hitachi, Ltd., delivered a lecture titled "Structure of magnetic flux observed by electron beam". Prof. Shigeru Kubono of University of Tokyo encouraged us through a talk of "Expectations for the JAEA-Tokai tandem accelerator". This workshop was held at Nuclear Science Research Institute on January 6-7th in 2009, having 24 oral presentations and 48 posters, as many as 120 participants.
Shizuma, Toshiyuki; Ishii, Tetsuro; Makii, Hiroyuki*; Hayakawa, Takehito; Matsuda, Makoto
European Physical Journal A, 39(3), p.263 - 266, 2009/03
Excited states in neutron-rich Ta have been studied using a two-neutron transfer reaction of Ta(O,O). In-beam -rays were measured in coincidence with scattered ions detected by a high-resolution - Si telescope for reaction channel selection. Previously known 1-quasiparticlebands are extended to higher spins, and several levels including a s, 3-quasiparticle isomer are identified.
Ishii, Tetsuro; Makii, Hiroyuki*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shigematsu, Soichiro*; Kaneko, Junichi*; Shizuma, Toshiyuki; et al.
Physical Review C, 78(5), p.054309_1 - 054309_11, 2008/11
Nakamura, Masahiko; Matsuda, Makoto; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Ishii, Tetsuro; Asai, Masato; Okura, Takehisa
JAEA-Technology 2008-052, 17 Pages, 2008/07
Alpha rays (0.06 Bq/cm) were detected on the first basement passage of the Tandem Accelerator Facility. We attempted to identify the alpha-emitting nuclide with surveying this area. We found a crack of concrete at the detected spot. We inferred that radon may seep out of the crack from several phenomena observed in the survey of this area. Furthermore, we identified all nuclides emitting rays at the crack as Naturally Occurring Radioactive Materials, (NORM: K, Bi, Ac and so on) by in-situ -ray measurement. Radon is not easy to be collected and detected by its nature of noble gas. We have developed a convenient electrostatic collection method: after collection of the radon decay product (Po) using a Teflon sheet charged electrostatically, we have measured alpha rays and rays from this sheet. We concluded the leakage of radon from the soil caused a high counting-rate of alpha rays. The paper describes our survey works and identification procedures in detail.
Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; et al.
Nuclear Physics A, 805(1-4), p.257 - 259, 2008/06
no abstracts in English
Shizuma, Toshiyuki; Ishii, Tetsuro; Makii, Hiroyuki*; Hayakawa, Takehito; Matsuda, Makoto; Shigematsu, Soichiro*; Ideguchi, Eiji*; Zheng, Y.*; Liu, M.*; Morikawa, Tsuneyasu*; et al.
Physical Review C, 77(4), p.047303_1 - 047303_4, 2008/04
Modest spin states in neutron-rich W have been populated using a W(O,O) one-neutron transfer reaction. While negative-parity bands previously known are extended to higher spin, two positive-parity bands are newly identified. Configurations based on i orbitals are assigned to these bands from an analysis of the level energy systematics as well as the g-factors derived from in-band branching ratios.
Hayashi, Hiroaki*; Akita, Yukinori*; Suematsu, Osamu*; Shibata, Michihiro*; Asai, Masato; Sato, Tetsuya; Ichikawa, Shinichi; Nishinaka, Ichiro; Nagame, Yuichiro; Osa, Akihiko; et al.
European Physical Journal A, 34(4), p.363 - 370, 2007/12
values of Eu and Gd were measured for the first time using a total absorption BGO detector, and the data of Pm, Sm, and Tb obtained previously were reanalyzed. These nuclei were produced by the proton-induced fission of U at the JAEA-Tokai tandem accelerator facility, and separated from the reaction products using an on-line isotope separator. The deduced mass excesses and two-neutron separation energies were compared with those of atomic mass evaluations and theoretical predictions.