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Journal Articles

In-beam $$gamma$$-ray spectroscopy of $$^{32}$$Mg via direct reactions

Kitamura, Noritaka*; Wimmer, K.*; Miyagi, Takayuki*; Poves, A.*; Shimizu, Noritaka*; Tostevin, J. A.*; Bader, V. M.*; Bancroft, C.*; Barofsky, D.*; Baugher, T.*; et al.

Physical Review C, 105(3), p.034318_1 - 034318_17, 2022/03

no abstracts in English

Journal Articles

Development of inter-digital H-mode drift-tube linac prototype with alternative phase focusing for a muon linac in the J-PARC muon g-2/EDM experiment

Nakazawa, Yuga*; Iinuma, Hiromi*; Iwata, Yoshiyuki*; Iwashita, Yoshihisa*; Otani, Masashi*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Yamazaki, Takayuki*; Yoshida, Mitsuhiro*; Kitamura, Ryo; et al.

Journal of Physics; Conference Series, 1350, p.012054_1 - 012054_7, 2019/12

 Times Cited Count:0 Percentile:0.07

An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the rf field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, tuners and coupler are designed and fabricated. In this paper, the development of the tuner and the coupler and the result of the low-power measurement will be presented.

Journal Articles

Negative muonium ion production with a C12A7 electride film

Otani, Masashi*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Matoba, Shiro*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Yamazaki, Takayuki*; Hasegawa, Kazuo; et al.

Journal of Physics; Conference Series, 1350, p.012067_1 - 012067_6, 2019/12

 Times Cited Count:0 Percentile:0.07

Negative muonium atom ($$mu^+$$e$$^-$$e$$^-$$, Mu$$^-$$) has unique features stimulating potential interesting for several scientific fields. Since its discovery in late 1980's in vacuum, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has relatively low-work function (2.9 eV). In this paper, the negative muonium production measurement with several materials including a C12A7 electride film will be presented. Measured production rate of the Mu$$^-$$ were 10$$^{-3}$$/s for all the Al, electride, and SUS target. Significant enhancement on electride target was not observed, thus it is presumed that the surface condition should be more carefully treated. There was no material dependence of the Mu$$^-$$ averaged energy: it was 0.2$$pm$$0.1keV.

Journal Articles

Thermodynamic interpretation of uranium(IV/VI) solubility in the presence of $$alpha$$-isosaccharinic acid

Kobayashi, Taishi*; Sasaki, Takayuki*; Kitamura, Akira

Journal of Chemical Thermodynamics, 138, p.151 - 158, 2019/11

 Times Cited Count:0 Percentile:0.01(Thermodynamics)

The effect of $$alpha$$-isosaccharinic acid (ISA) on the solubility and redox of tetravalent and hexavalent uranium (U(IV), U(VI)) was investigated in the hydrogen ion concentration (pH$$_{c}$$) range of 6$$sim$$13 and at total ISA concentration ([ISA]$$_{rm tot}$$) = 10$$^{-4}$$$$sim$$10$$^{-1.2}$$ mol/dm$$^{3}$$. The dependence of U(IV) solubility on pH$$_{c}$$ and [ISA]$$_{rm tot}$$ suggested the existence of U(OH)$$_{4}$$(ISA)$$_{2}$$$$^{2-}$$ as a dominant species within the investigated pH$$_{c}$$ range of 6$$sim$$12. For the U(VI)-ISA system, UO$$_{2}$$(OH)$$_{3}$$(ISA)$$_{2}$$$$^{2-}$$ was suggested as a dominant species at pH$$_{c}$$ 7$$sim$$13. The formation constants of the U(IV)-ISA and U(VI)-ISA complexes were determined by least-squares fitting of the solubility data. The solubility of U(IV) and U(VI) in the presence of ISA and its effect on the redox behavior were thermodynamically interpreted based on the obtained constants.

Journal Articles

Beam commissioning of muon beamline using negative hydrogen ions generated by ultraviolet light

Nakazawa, Yuga*; Bae, S.*; Choi, H.*; Choi, S.*; Iijima, Toru*; Iinuma, Hiromi*; Kawamura, Naritoshi*; Kitamura, Ryo; Kim, B.*; Ko, H. S.*; et al.

Nuclear Instruments and Methods in Physics Research A, 937, p.164 - 167, 2019/09

 Times Cited Count:1 Percentile:23.13(Instruments & Instrumentation)

A muon linac is under development for the precise measurement of the muon anomalous magnetic moment ($$g$$-2) and electric dipole moment (EDM) with a reaccelerated thermal muon beam. An H$$^-$$ source driven by an ultraviolet light has been developed for the muon acceleration experiment. Prior to the acceleration experiment, a beamline commissioning was performed using this H$$^-$$ beam, since the accelerated muon intensity is very low. We successfully measured the magnetic rigidity, which is essential for identifying the accelerated muons. This H$$^-$$ source is capable of utilizing as a general-purpose beam source for other beamline.

Journal Articles

Prototype of an Inter-digital H-mode Drift-Tube Linac for muon linac

Nakazawa, Yuga*; Iinuma, Hiromi*; Iwata, Yoshiyuki*; Iwashita, Yoshihisa*; Otani, Masashi*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Yamazaki, Takayuki*; Yoshida, Mitsuhiro*; Kitamura, Ryo*; et al.

Proceedings of 29th International Linear Accelerator Conference (LINAC 2018) (Internet), p.180 - 183, 2019/01

We have developed an Interdigital H-mode (IH) Drift-Tube Linac (DTL) design with an alternative phase focusing (APF) scheme for a muon linac, in order to measure the anomalous magnetic moment and electric dipole moment (EDM) of muons at the Japan Proton Accelerator Research Complex (J-PARC). The IH-DTL accelerates muons from beta 0.08 to 0.28 at an operational frequency of 324 MHz. The output beam emittances are calculated as 0.315 $$pi$$ and 0.195 $$pi$$ mm mrad in the horizontal and vertical directions, respectively, which satisfies the experimental requirement.

Journal Articles

A Thermodynamic model for ZrO$$_{2}$$(am) solubility at 25$$^{circ}$$C in the Ca$$^{2+}$$-Na$$^{+}$$-H$$^{+}$$-Cl$$^{-}$$-OH$$^{-}$$-H$$_{2}$$O system; A Critical review

Rai, D.*; Kitamura, Akira; Altmaier, M.*; Rosso, K. M.*; Sasaki, Takayuki*; Kobayashi, Taishi*

Journal of Solution Chemistry, 47(5), p.855 - 891, 2018/05

 Times Cited Count:5 Percentile:8.63(Chemistry, Physical)

We have critically reviewed experimental data for Zr hydrolysis constant values for formation of several mononuclear and polynuclear species and a solubility product value for ZrO$$_{2}$$(am). We have determined new/revised values for the formation constants of Zr(OH)$$_{2}$$$$^{2+}$$, Zr(OH)$$_{4}$$(aq), Zr(OH)$$_{5}$$$$^{-}$$, Zr(OH)$$_{6}$$$$^{2-}$$ and Ca$$_{3}$$Zr(OH)$$_{6}$$$$^{4+}$$, and the solubility product for ZrO$$_{2}$$(am) after the critical review.

Journal Articles

First muon acceleration using a radio-frequency accelerator

Bae, S.*; Choi, H.*; Choi, S.*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Hasegawa, Kazuo; Iijima, Toru*; Iinuma, Hiromi*; Ishida, Katsuhiko*; Kawamura, Naritoshi*; et al.

Physical Review Accelerators and Beams (Internet), 21(5), p.050101_1 - 050101_6, 2018/05

 Times Cited Count:11 Percentile:81.67(Physics, Nuclear)

Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu$$^{-}$$), which are bound states of positive muons and two electrons, are generated from through the electron capture process in an aluminum degrader. The generated Mu$$^{-}$$'s are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ). In the RFQ, the Mu$$^{-}$$'s are accelerated to 89 keV. The accelerated Mu$$^{-}$$'s are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.

Journal Articles

Thermodynamic model for Zr solubility in the presence of gluconic acid and isosaccharinic acid

Kobayashi, Taishi*; Teshima, Takeshi*; Sasaki, Takayuki*; Kitamura, Akira

Journal of Nuclear Science and Technology, 54(2), p.233 - 241, 2017/02

 Times Cited Count:3 Percentile:40.62(Nuclear Science & Technology)

Zr solubility in the presence of gluconic acid (GLU) and isosaccharinic acid (ISA) was investigated as a function of hydrogen ion concentration (pH$$_{rm c}$$) and the total concentration of GLU or ISA. The dependence of the increase in Zr solubility on the pH$$_{rm c}$$ and GLU concentration suggested the existence of Zr(OH)$$_{4}$$(GLU)$$_{2}$$$$^{2-}$$ in the neutral pH region and Zr(OH)$$_{4}$$(GLU)(GLU$$_{rm -H}$$)$$^{3-}$$ in the alkaline pH region above pH$$_{rm c}$$ 10 as the dominant species in the presence of 10$$^{-3}$$ - 10$$^{-1}$$ mol/dm$$^{3}$$ (M) GLU. In the presence of ISA, the dominant species Zr(OH)$$_{4}$$(ISA)$$_{2}$$$$^{2-}$$ and Zr(OH)$$_{4}$$(ISA)(ISA$$_{rm -H}$$)$$^{3-}$$ were proposed to occur in the neutral and alkaline pH regions, similar to those found in the presence of GLU. From X-ray diffraction analysis, the solubility-limiting solid phase in the presence of GLU and ISA was considered to be Zr(OH)$$_{4}$$(am). The formation constants of the Zr gluconate and isosaccharinate complexes were determined by least squares fitting analysis of the solubility data, and the obtained values were discussed in comparison with those of tetravalent actinides.

Journal Articles

Issues concerning the determination of solubility products of sparingly soluble crystalline solids; Solubility of HfO$$_{2}$$(cr)

Rai, D.*; Kitamura, Akira; Rosso, K. M.*; Sasaki, Takayuki*; Kobayashi, Taishi*

Radiochimica Acta, 104(8), p.583 - 592, 2016/08

 Times Cited Count:4 Percentile:45.9(Chemistry, Inorganic & Nuclear)

Solubility studies were conducted with HfO$$_{2}$$(cr) solid as a function of acid concentrations. These studies involved (1) using two different amounts of the solid phase, (2) acid washing the bulk solid phase, (3) preheating the solid phase to 1400 $$^{circ}$$C, and (4) heating amorphous HfO$$_{2}$$(am) suspensions to 90 $$^{circ}$$C to ascertain whether the HfO$$_{2}$$(am) converts to HfO$$_{2}$$(cr) and to determine the solubility from the oversaturation direction. Based on the results of these treatments it is concluded that the HfO$$_{2}$$(cr) contains a small fraction of less crystalline, but not amorphous, material [HfO$$_{2}$$(lcr)] and this, rather than the HfO$$_{2}$$(cr), is the solubility-controlling phase in the range of experimental variables investigated in this study. The solubility data are interpreted using both the Pitzer and SIT models. The log$$_{10}$$ of the solubility product of HfO$$_{2}$$(cr) is estimated. The observation of a small fraction of less crystalline higher solubility material is consistent with the general picture that mineral surfaces are often structurally and/or imperfect leading to a higher solubility than the bulk crystalline solid. This study stresses the urgent need, during interpretation of solubility data, of taking precautions to make certain that the observed solubility behavior for sparingly-soluble solids is assigned to the proper solid phase.

Journal Articles

Current status of electrostatic accelerator at TIARA

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

Dai-28-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.117 - 119, 2015/12

no abstracts in English

Journal Articles

Ion-track grafting of vinylbenzyl chloride into poly(ethylene-$$co$$-tetrafluoroethylene) films using different media

Nuryanthi, N.*; Yamaki, Tetsuya; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari; Suzuki, Akihiro*; et al.

Transactions of the Materials Research Society of Japan, 40(4), p.359 - 362, 2015/12

The ion-track grafting of a vinylbenzyl chloride (VBC) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film is necessary for preparing nanostructured hydroxide-ion-conductive electrolyte membranes. A key for success here is to obtain as high graft levels as possible (for higher conductivity) in a smaller number of tracks (for improving the other membrane properties). To this end, therefore, the effect of the medium for the VBC grafting was investigated as part of our continuing effort to optimize the experimental conditions. A 25 $$mu$$m-thick ETFE film was irradiated in a vacuum chamber with 560 MeV $$^{129}$$Xe at different fluences, and then the grafting was performed by immersing the irradiated films in a 20vol% VBC monomer at 60$$^{circ}$$C. A medium was a mixture of water (H$$_{2}$$O) and isopropyl alcohol (iPrOH) at different volume ratios. The degree of grafting increased as the H$$_{2}$$O content became higher, and reached a maximum in pure H$$_{2}$$O. These results can be explained by considering the well-known Trommsdorff effect, in which poor solubility of the grafted polymer in polar media leads to an increased polymerization rate probably due to a lower termination rate.

Journal Articles

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

no abstracts in English

Journal Articles

Investigation into cause of increasing count rate on PIMS at RRP, 1; Search of potential causes

Mukai, Yasunobu; Nakamura, Hironobu; Nakamichi, Hideo; Kurita, Tsutomu; Noguchi, Yoshihiko*; Tamura, Takayuki*; Ikegame, Ko*; Shimizu, Junji*

Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07

The PIMS used at Rokkasho Reprocessing Plant can quantify plutonium amount in each process vessel located inside glovebox by means of neutron measurement. Since the PIMS is not used for the neutron coincidence counting, it is very important to maintain that those constants meet the actual process condition. PIMS was calibrated in 2006, and then JNFL has been started to measure the Pu amount directly in each glovebox for the purpose of facility NMA. However, it was found that PIMS counting was unexpectedly and continuously increased during long time of inter-campaign. In order to find out the main cause, JAEA and JNFL jointly conducted several investigations. In the investigations, correctness of system parameters and relevant constants, behavior of the neutron generation when MOX powder is stored in actual glovebox for a long time (to see O/M and moisture change) and the behavior focused on the relation between MOX powder and light element using inside glovebox (fluorine is included in the PTFE which is used in many gloveboxes as packing of instruments) were experimentally confirmed using MOX powder in PCDF. As a result, since the same behavior happened in the actual PIMS was confirmed in the testing environment in which MOX powder coexists with fluorine, it is concluded that the main potential cause of PIMS is the increasing of the probability of ($$alpha$$, $$n$$) reactions by a contact between PTFE and MOX powder.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage, 2; Progress report on NUMO-JAEA collaborative research in FY2012 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Hayano, Akira; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.

JAEA-Research 2013-037, 455 Pages, 2013/12

JAEA-Research-2013-037.pdf:42.0MB

Following FY2011, JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, the tree diagram of methodology of groundwater travel time has been extended for crystalline rock, in addition, tree diagram for sedimentary rock newly has been organized. With regard to (2) study on scenario development, the existing approach has been improved in terms of a practical task, and applied and tested for near field focusing on the buffer. In addition, the uncertainty of some important processes and its impact on safety functions are discussed though analysis. With regard to (3) study on setting radionuclide migration parameters, the approaches for parameter setting have been developed for sorption for rocks and solubility, and applied and tested through parameter setting exercises for key radionuclides.

Journal Articles

Sorption behavior of nickel and palladium in the presence of NH$$_{3}$$(aq)/NH$$_{4}$$$$^{+}$$

Kobayashi, Taishi*; Sasaki, Takayuki*; Ueda, Kenyo*; Kitamura, Akira

Materials Research Society Symposium Proceedings, Vol.1518, p.231 - 236, 2013/10

For the nuclear waste management of TRU waste, it is necessary to assess the impact of nitrate salts contained in the waste. In the present study, the sorption behavior of Ni and Pd on the pumice tuff was investigated in the presence of NH$$_{3}$$(aq)/NH$$_{4}$$$$^{+}$$. Under different NH$$_{3}$$(aq)/NH$$_{4}$$$$^{+}$$ concentration, pH and ionic strength conditions, distribution coefficient ($$K_{rm d}$$) of Ni and Pd on the pumice tuff was determined by batch experiment. For Ni system, the $$K_{rm d}$$ values showed no significant dependence on the initial NH$$_{4}$$$$^{+}$$ concentration in neutral pH region, agrees with the prediction from thermodynamic data. For Pd system, the $$K_{rm d}$$ values decreased with an increase of [NH$$_{4}$$$$^{+}$$]ini, suggesting the formation of stable ammine complex (Pd(NH$$_{3}$$)$$_{m}$$$$^{2+}$$ ($$m$$: 1 - 4)). The obtained $$K_{rm d}$$ values for Ni and Pd were analyzed using the surface complexation model. By taking complexes predicted by thermodynamic data into account, the sorption behavior of Ni and Pd in the presence of NH$$_{3}$$(aq)/NH$$_{4}$$$$^{+}$$ were well explained.

Journal Articles

Decontamination of school facilities in Fukushima-city

Yoshikawa, Hideki; Iijima, Kazuki; Sasamoto, Hiroshi; Fujiwara, Kenso; Mitsui, Seiichiro; Kitamura, Akira; Kurikami, Hiroshi; Tokizawa, Takayuki; Yui, Mikazu; Nakayama, Shinichi

Materials Research Society Symposium Proceedings, Vol.1518, p.269 - 275, 2013/10

Following the release of radionuclides into the environment as a result of the accident at Fukushima Daiichi Nuclear Power Plant, Japan Atomic Energy Agency (JAEA) had to develop an immediate and effective method of reducing the dose rate received by students in school facilities. A demonstration of a reducing method was carried out by JAEA at a junior high school ground and kindergarten yard in the center of Fukushima-city. Dose rates of the released radionuclides are largely controlled by the ground level contamination and accumulation of mainly cesium-137 ($$^{137}$$Cs) and cesium-134 ($$^{134}$$Cs) in populated areas. An effective means of reducing dose rate was to remove the surface soil and to bury it on-site under fresh uncontaminated soil or soil collected under deep depth at the site for shielding. The dose rate at1 m above ground level was reduced from 2.5 $$mu$$Sv/h to 0.15 $$mu$$Sv/h.

Journal Articles

Applicability of iron phosphate glass medium for loading NaCl originated from seawater used for cooling the stricken power reactors

Kobayashi, Hidekazu; Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 6 Pages, 2013/09

no abstracts in English

Journal Articles

Behaviour of IPG waste forms bearing BaSO$$_{4}$$ as the dominant sludge constituent generated from the treatment of water used for cooling the stricken power reactors

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 8 Pages, 2013/09

The great amount of water used for cooling the stricken power reactors at Fukushima Dai-ichi has resulted in accumulation of "remaining water". As the remaining water is subsequently contaminated by FPs, etc., it is necessary to decontaminate it in order to reduce the volume of liquid radioactive waste and to reuse it again for cooling the reactors. Various techniques are being applied to remove FP, etc. and to make stable waste forms. One of the methods using the iron phosphate glass as a medium is being developed to stabilize the strontium-bearing sludge whose main component is BaSO$$_{4}$$. From the results hitherto, the iron phosphate glass is regarded as a potential medium for the target sludge.

Journal Articles

Morphological change of self-organized protrusions of fluoropolymer surface by ion beam irradiation

Kitamura, Akane; Kobayashi, Tomohiro*; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Suzuki, Akihiro*; Terai, Takayuki*

Nuclear Instruments and Methods in Physics Research B, 307, p.614 - 617, 2013/07

 Times Cited Count:7 Percentile:54.8(Instruments & Instrumentation)

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