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Journal Articles

Evaluation of vacuum firing effect on stainless steel from vacuum and surface point of view

Kamiya, Junichiro; Takano, Kazuhiro*; Wada, Kaoru; Yanagibashi, Toru*

e-Journal of Surface Science and Nanotechnology (Internet), 21(3), p.144 - 153, 2023/06

no abstracts in English

Journal Articles

Evaluation of titanium vacuum chamber as getter pump

Kamiya, Junichiro; Takano, Kazuhiro*; Yuza, Hiromu*; Wada, Kaoru

e-Journal of Surface Science and Nanotechnology (Internet), 20(2), p.107 - 118, 2022/05

no abstracts in English

JAEA Reports

Noise countermeasures for inverter-controlled multi-stage roots vacuum pumps in J-PARC LINAC L3BT

Takano, Kazuhiro; Kotoku, Hirofumi*; Kobayashi, Fuminori*; Miyao, Tomoaki*; Moriya, Katsuhiro; Kamiya, Junichiro

JAEA-Technology 2021-017, 35 Pages, 2021/11

JAEA-Technology-2021-017.pdf:5.32MB

In J-PARC LINAC, the vacuum system of L3BT, which is a beam transport line connecting LINAC and 3GeV synchrotron, uses a turbo molecular pump and roots pump for rough exhaust and an ion pump for main exhaust. In addition, beam dumps are connected to the end of the L3BT at 0 degree, 30 degree, 90 degree, and 100 degree positions via vacuum partition windows. The roots pumps are used as the exhaust system for each beam dump. The roots pump controllers have been installed away from the pump in the accelerator tunnel to avoid radiation damages. Besides, the special controllers, which have no inverter circuit inside, have been used to reduce the electrical noise on the beam loss monitors nearby. However, using the special controller without inverters, several problems have occurred such as the instability or wide variability of the pumping speed. To solve such problems, the roots pump controller with the inverter circuit must be used after reducing the electrical noise. In this report, some countermeasures to reduce the electrical noise from the inverters were investigated. The noise reduction circuit was successfully optimized to the level where the beam loss monitors works unaffected.

Journal Articles

Improved vacuum system for high-power proton beam operation of the rapid cycling synchrotron

Kamiya, Junichiro; Kotoku, Hirofumi*; Kurosawa, Shunta*; Takano, Kazuhiro; Yanagibashi, Toru*; Yamamoto, Kazami; Wada, Kaoru

Physical Review Accelerators and Beams (Internet), 24(8), p.083201_1 - 083201_23, 2021/08

 Times Cited Count:0 Percentile:0.02(Physics, Nuclear)

Through the operation of the vacuum system in J-PARC, it becomes evident that the high-power beam has more powerful effects on the vacuum system than expected. Those effects are the malfunction of vacuum equipment and the large pressure rise. The former is the failure of the turbomolecular pump (TMP) controller. The TMP itself is also damaged by a bearing crush due to a touch-down. We have developed a TMP controller that can connect with long cables of more than 200 m lengths to install the controller in a control room where there is no radiation influence. The TMP with high-strength bearing has been also developed. The latter is an extreme pressure rise with increasing the beam power. It is indicated that the pressure rise mechanism is a result of ion-stimulated gas desorption. It is finally confirmed that the dynamic pressure during the high-power beam is effectually suppressed by additionally installing the NEG pumps.

Journal Articles

Some methods of making titanium vacuum chamber act as getter pump for UHV/XHV

Kamiya, Junichiro; Takano, Kazuhiro; Yuza, Hiromu*; Wada, Kaoru

Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.3471 - 3474, 2021/08

The NEG coating, which has been developed in CERN, is a revolutionary technique that can make a beam pipe act as a vacuum pump by coating the getter materials with the ability to adsorb/absorb gas molecules on the beam pipe surface. The NEG materials are alloys of titanium, zirconium, and vanadium. Titanium is one of the getter materials. In high-power beam accelerators, titanium has been used as the beam pipe chamber material due to its low radioactivation characteristics. The ordinal titanium surface has no getter function because it is covered with titanium-oxide film. The new technique, which removes the titanium-oxide surface by the sputtering and makes the titanium vacuum chamber itself the vacuum pump like NEG coated chamber, has been developed. After sputtering the inner surface of the titanium chamber, we obtained clear evidence that shows the chamber acts as a vacuum pump. We have also tried to make a titanium chamber with a getter function only by baking. Dependence of the getter characteristics on the baking temperature will also be reported.

Journal Articles

Flexible fuel cycle system for the effective management of plutonium

Fukasawa, Tetsuo*; Hoshino, Kuniyoshi*; Yamashita, Junichi*; Takano, Masahide

Journal of Nuclear Science and Technology, 57(11), p.1215 - 1222, 2020/11

 Times Cited Count:1 Percentile:12.47(Nuclear Science & Technology)

The flexible fuel cycle initiative system (FFCI system) has been developed to reduce spent fuel (SF) amounts, to keep high availability factor for the reprocessing plant and to increase the proliferation resistance for the recovered Pu. The system separates most U from the SF at first, and the residual material called recycle material (RM) which contains Pu, minor actinides, fission products and remaining U will go to Pu(+U) recovery from the RM for Pu utilizing reactor in future. The Pu utilizing reactor is FBR or LWR with MOX fuel. The RM is the buffer material between SF reprocessing and Pu utilizing reactor with compact size and high proliferation resistance, which can suppress the amount of relatively pure Pu. The innovative technologies of FFCI are most U separation and temporary RM storage. They are investigated by the literature survey, fundamental experiments using simulated material and analyses using simulation code. This paper summarizes the feasibility confirmation results of FFCI.

Journal Articles

Induction of Fusarium wilt resistant by ion beam irradiation in strawberry (${it Fragaria}$ $$times$$ ${it ananassa}$) leaf explants

Yotoriyama, Mamoru*; Takano, Junichi*; Namai, Kiyoshi*; Yoshihara, Ryohei; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issei

JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 71, 2011/01

no abstracts in English

Journal Articles

Performance of the main ring BPM during the beam commissioning at J-PARC

Toyama, Takeshi*; Arakawa, Dai*; Hiramatsu, Shigenori*; Igarashi, Susumu*; Lee, S.*; Matsumoto, Hiroshi*; Odagiri, Junichi*; Tejima, Masaki*; Tobiyama, Makoto*; Hashimoto, Yoshinori*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.981 - 983, 2010/05

Experiences of operating BPM's during beam commissioning at the J-PARC MR are reported. The subjects are: (1) bug report, statistics and especially the effect of a beam duct step, (2) position resolution estimation ($$<$$30 micrometers with 1 sec averaging), (3) beam based alignment.

Journal Articles

Dose response of ion beam irradiation in strawberry (${it Fragaria}$ $$times$$ ${it ananassa}$) leaf explants

Takano, Junichi*; Namai, Kiyoshi*; Yoshihara, Ryohei; Hase, Yoshihiro; Narumi, Issei

JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 80, 2009/12

no abstracts in English

Journal Articles

Characterization of electrode/electrolyte interface for lithium batteries using ${it in situ}$ synchrotron X-ray reflectometry; A New experimental technique for LiCoO$$_{2}$$ model electrode

Hirayama, Masaaki*; Sonoyama, Noriyuki*; Abe, Takashi*; Minoura, Machiko*; Ito, Masumi*; Mori, Daisuke*; Yamada, Atsuo*; Kanno, Ryoji*; Terashima, Takahito*; Takano, Mikio*; et al.

Journal of Power Sources, 168(2), p.493 - 500, 2007/06

 Times Cited Count:84 Percentile:90.06(Chemistry, Physical)

A new experimental technique was developed for detecting structure changes at electrode/electrolyte interface of lithium cell using X-ray reflectometry and two-dimensional model electrodes with a restricted lattice-plane. The electrodes were constructed with an epitaxial film of LiCoO$$_{2}$$ synthesized by pulsed laser deposition method. The anisotropic properties were confirmed by electrochemical measurements. ${it Ex situ}$ X-ray reflectivity measurements indicated that the impurity layer existed on the as-grown LiCoO$$_{2}$$ was dissolved and a new SEI layer with lower density was formed after soaking into the electrolyte. ${it In situ}$ X-ray reflectivity measurements indicated that the surface roughness of the intercalation (1 1 0) plane increased with applying voltages, while no significant changes in surface morphology were observed for the intercalation non-active (0 0 3) plane during the pristine stage of the charge-discharge process.

Journal Articles

Phonon softening in superconducting diamond

Hoesch, M.*; Fukuda, Tatsuo; Mizuki, Junichiro; Takenouchi, Tomohiro*; Kawarada, Hiroshi*; Sutter, J. P.*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Nagao, Masanori*; Takano, Yoshihiko*

Physical Review B, 75(14), p.140508_1 - 140508_4, 2007/04

 Times Cited Count:35 Percentile:77.53(Materials Science, Multidisciplinary)

We observed phonon dispersions using inelastic X-ray scattering from CVD-grown high quality superconducting ($$T_c$$=4.2 K) boron-doped and non-doped diamonds. By comparing these two, we found almost no change in the acoustic branch along both [111] and [001] directions. On the other hand, strong softening were observed in the optical branch of the boron-doped diamond in both directions: about 2 meV at Brillouin zone boundary and 8 meV at zone center ($$Gamma$$ point). From this result we estimated the electron-phonon coupling factor $$lambda$$=0.33, and this supports theoretical models suggesting a phonon-mediated pairing mechanism via coupling of optical phonon modes to Fermi surfaces around the $$Gamma$$ point.

Journal Articles

Research activities of Japanese Nuclear Data Committee in the fiscal years of 2001 and 2002

Igashira, Masayuki*; Shibata, Keiichi; Takano, Hideki*; Yamano, Naoki*; Matsunobu, Hiroyuki*; Kitao, Kensuke*; Katakura, Junichi; Nakagawa, Tsuneo; Hasegawa, Akira; Iwasaki, Tomohiko*; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(1), p.128 - 139, 2004/03

no abstracts in English

Journal Articles

Charge-ordered state in single-crystalline CaFeO$$_{3}$$ thin film studied by X-ray anomalous diffraction

Akao, Tadahiro*; Azuma, Yusuke; Usuda, Manabu; Nishihata, Yasuo; Mizuki, Junichiro; Hamada, Noriaki*; Hayashi, Naoaki*; Terashima, Takahito*; Takano, Mikio*

Physical Review Letters, 91(15), p.156405_1 - 156405_4, 2003/10

 Times Cited Count:34 Percentile:79.64(Physics, Multidisciplinary)

X-ray anomalous diffraction, together with a band structure calculation, was employed to obtain a quantitative comprehension of the charge-ordering state in a single-crystalline CaFeO$$_{3}$$ thin film. The experimental results show a characteristic energy dispersion of the near inhibited reflection at 150, implying Fe atoms split into two distinct states. The energy dispersion is in good agreement with the calculated spectrum based on LDA+U scheme. The calculation reveals an electronic configuration of the Fe 3d orbital follows a localization in the oxygen orbital surrounds one of the distinct Fe atoms.

Journal Articles

Japanese evaluated nuclear data library version 3 revision-3; JENDL-3.3

Shibata, Keiichi; Kawano, Toshihiko*; Nakagawa, Tsuneo; Iwamoto, Osamu; Katakura, Junichi; Fukahori, Tokio; Chiba, Satoshi; Hasegawa, Akira; Murata, Toru*; Matsunobu, Hiroyuki*; et al.

Journal of Nuclear Science and Technology, 39(11), p.1125 - 1136, 2002/11

 Times Cited Count:658 Percentile:96.97(Nuclear Science & Technology)

Evaluation for JENDL-3.3 has been performed by considering the accumulated feedback information and various benchmark tests of the previous library JENDL-3.2. The major problems of the JENDL-3.2 data were solved by the new library: overestimation of criticality values for thermal fission reactors was improved by the modifications of fission cross sections and fission neutron spectra for $$^{235}$$U; incorrect energy distributions of secondary neutrons from important heavy nuclides were replaced with statistical model calculations; the inconsistency between elemental and isotopic evaluations was removed for medium-heavy nuclides. Moreover, covariance data were provided for 20 nuclides. The reliability of JENDL-3.3 was investigated by the benchmark analyses on reactor and shielding performances. The results of the analyses indicate that JENDL-3.3 predicts various reactor and shielding characteristics better than JENDL-3.2.

Journal Articles

First test results for the ITER central solenoid model coil

Kato, Takashi; Tsuji, Hiroshi; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Kawano, Katsumi; Oshikiri, Masayuki*; et al.

Fusion Engineering and Design, 56-57, p.59 - 70, 2001/10

 Times Cited Count:17 Percentile:74.89(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Progress of the ITER central solenoid model coil programme

Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.

Nuclear Fusion, 41(5), p.645 - 651, 2001/05

 Times Cited Count:55 Percentile:83.06(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

JNDC nuclear data library of fission products; Second version

Tasaka, Kanji; Katakura, Junichi; Ihara, Hitoshi; Yoshida, Tadashi*; Iijima, Shungo*; Nakashima, Ryuzo*; Nakagawa, Tsuneo; Takano, Hideki

JAERI 1320, 253 Pages, 1990/09

JAERI-1320.pdf:10.61MB

no abstracts in English

Oral presentation

Phonon softening in boron doped diamond

Fukuda, Tatsuo; Hoesch, M.*; Takenouchi, Tomohiro*; Sutter, J. P.*; Tsutsui, Satoshi*; Baron, A.*; Nagao, Masanori*; Takano, Yoshihiko*; Kawarada, Hiroshi*; Mizuki, Junichiro

no journal, , 

Diamond is well known for its maximum hardness, large energy gap, high thermal conductivity, and so on. In addition to these, the superconductivity was discovered recently in boron doped (B-doped) diamond, and this was soon confirmed by other groups. We performed inelastic X-ray scattering experiments at BL35XU of SPring-8 to measure phonons in a highly B-doped CVD grown diamond having superconducting transition at $$T_csimeq$$4.2 K. By comparing the experimental results with those from nitrogen doped CVD grown diamond and/or pure diamond, we found that the optical modes are softened especially at around the Brillouin zone center along with a strong broadening, while the acoustic modes do not show both softening and broadening. This confirms the strong electron-phonon coupling in superconducting diamond.

Oral presentation

Generation of strawberry yellows-resistant variety of Tochiotome by ion beam irradiation; Regeneration rate and inoculation test

Yotoriyama, Mamoru*; Takano, Junichi*; Namai, Kiyoshi*; Yoshihara, Ryohei; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

Magnetism and local structures of new ferromagnet BaFeO$$_{3}$$ and related materials

Yoshii, Kenji; Hayashi, Naoaki*; Matsumura, Daiju; Kusano, Shogo*; Mizumaki, Masaichiro*; Mizuki, Junichiro*; Takano, Mikio*

no journal, , 

We have investigated the magnetocaloric effect of BaFeO$$_{3}$$ and related materials. The substitutions at Ba and Fe sites was found to lead to a suppression of ground-state antiferromagnetic ordering. Hence, hysteretic losses are suppressed by the substitution, a property which is favorable to practical application. From EXAFS measurements using synchrotron radiation, BaFeO$$_{3}$$ involves a local structural distortion around Fe, whereas such behavior is suppressed by the substitutions. This may be related to the suppression of antiferromagnetic state, whose details will be presented at the conference.

23 (Records 1-20 displayed on this page)