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Journal Articles

Dynamics of radiocaesium within forests in Fukushima; Results and analysis of a model inter-comparison

Hashimoto, Shoji*; Tanaka, Taku*; Komatsu, Masabumi*; Gonze, M.-A.*; Sakashita, Wataru*; Kurikami, Hiroshi; Nishina, Kazuya*; Ota, Masakazu; Ohashi, Shinta*; Calmon, P.*; et al.

Journal of Environmental Radioactivity, 238-239, p.106721_1 - 106721_10, 2021/11

 Times Cited Count:0 Percentile:0(Environmental Sciences)

This study was aimed at analysing performance of models for radiocesium migration mainly in evergreen coniferous forest in Fukushima, by inter-comparison between models of several research teams. The exercise included two scenarios of countermeasures against the contamination, namely removal of soil surface litter and forest renewal, and a specific konara oak forest scenario in addition to the evergreen forest scenario. All the models reproduced trend of time evolution of radiocesium inventories and concentrations in each of the components in forest such as leaf and organic soil layer. However, the variations between models enlarged in long-term predictions over 50 years after the fallout, meaning continuous field monitoring and model verification/validation is necessary.

Journal Articles

Study of the axial $$U(1)$$ anomaly at high temperature with lattice chiral fermions

Aoki, Sinya*; Aoki, Yasumichi*; Cossu, G.*; Fukaya, Hidenori*; Hashimoto, Shoji*; Kaneko, Takashi*; Rohrhofer, C.*; Suzuki, Kei

Physical Review D, 103(7), p.074506_1 - 074506_18, 2021/04

 Times Cited Count:2 Percentile:82.86(Astronomy & Astrophysics)

We investigate the axial $$U(1)$$ anomaly of two-flavor QCD at temperatures 190-330 MeV. In order to preserve precise chiral symmetry on the lattice, we employ the M$"o$bius domain-wall fermion action as well as overlap fermion action implemented with a stochastic reweighting technique. Compared to our previous studies, we reduce the lattice spacing to 0.07 fm, simulate larger multiple volumes to estimate finite size effect, and take more than four quark mass points, including one below physical point to investigate the chiral limit. We measure the topological susceptibility, axial $$U(1)$$ susceptibility, and examine the degeneracy of $$U(1)$$ partners in meson/baryon correlators. All the data above the critical temperature indicate that the axial $$U(1)$$ violation is consistent with zero within statistical errors. The quark mass dependence suggests disappearance of the $$U(1)$$ anomaly at a rate comparable to that of the $$SU(2)_L times SU(2)_R$$ symmetry breaking.

Journal Articles

Axial U(1) symmetry and mesonic correlators at high temperature in $$N_f=2$$ lattice QCD

Suzuki, Kei; Aoki, Sinya*; Aoki, Yasumichi*; Cossu, G.*; Fukaya, Hidenori*; Hashimoto, Shoji*; Rohrhofer, C.*

Proceedings of Science (Internet), 363, 7 Pages, 2020/08

We investigate the high-temperature phase of QCD using lattice QCD simulations with $$N_f=2$$ dynamical M$"o$bius domain-wall fermions. On generated configurations, we study the axial $$U(1)$$ symmetry, overlap-Dirac spectra, screening masses from mesonic correlators, and topological susceptibility. We find that some of the observables are quite sensitive to lattice artifacts due to a small violation of the chiral symmetry. For those observables, we reweight the M$"o$bius domain-wall fermion determinant by that of the overlap fermion. We also check the volume dependence of observables. Our data near the chiral limit indicates a strong suppression of the axial $$U(1)$$ anomaly at temperatures $$geq$$ 220 MeV.

Journal Articles

Symmetries of the light hadron spectrum in high temperature QCD

Rohrhofer, C.*; Aoki, Yasumichi*; Cossu, G.*; Fukaya, Hidenori*; Gattringer, C.*; Glozman, L. Ya.*; Hashimoto, Shoji*; Lang, C. B.*; Suzuki, Kei

Proceedings of Science (Internet), 363, 7 Pages, 2020/08

Properties of QCD matter change significantly around the chiral crossover temperature, and the effects on $$U(1)_A$$ and topological susceptibilities, as well as the meson spectrum have been studied with much care. Baryons and the effect of parity doubling in this temperature range have been analyzed previously by various other groups employing different setups. Here we construct suitable operators to investigate chiral and axial $$U(1)_A$$ symmetries in the baryon spectrum. Measurements for different volumes and quark-masses are done with two flavors of chirally symmetric domain-wall fermions at temperatures above the critical one. The possibility of emergent $$SU(4)$$ and $$SU(2)_{CS}$$ symmetries is discussed.

Journal Articles

Anomalous radioisotope production for $$^{68}$$ZnO using polyethylene by accelerator neutrons

Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Shintaro; Minato, Futoshi; Kawabata, Masako*; Hatsukawa, Yuichi*; Hashimoto, Kazuyuki*; Watanabe, Satoshi*; Saeki, Hideya*; Motoishi, Shoji*

Journal of the Physical Society of Japan, 89(3), p.034201_1 - 034201_7, 2020/03

 Times Cited Count:2 Percentile:51.78(Physics, Multidisciplinary)

We found anomalously large yields of $$^{67}$$Ga, $$^{66}$$Ga, $$^{rm 69m}$$Zn and $$^{64}$$Cu by neutron irradiation on a $$^{68}$$ZnO sample in a polyethylene shield. Neutron beams are generated from the $$^{9}$$Be($$d,n$$) reaction for 50 MeV deuterons. The yields obtained were more than 20 times larger than those in the unshielded sample. On the other hand, the yields of $$^{67}$$Ga, $$^{66}$$Ga, $$^{rm 69m}$$Zn and $$^{64}$$Cu from a metallic $$^{68}$$Zn sample and the yields of $$^{67}$$Cu, $$^{65}$$Ni and $$^{65}$$Zn from the $$^{68}$$ZnO and $$^{68}$$Zn samples were almost insensitive to the shield conditions. This finding would provide us a unique capability of accelerator neutrons to simultaneously produce a large amount of several radioisotopes, including proton induced reaction products, by using a single sample. The experimental data were compared with the yields estimated by using the Particle and Heavy Ion Transport code System and the result was discussed.

Journal Articles

$$^{99}$$Mo yield using large sample mass of MoO$$_{3}$$ for sustainable production of $$^{99}$$Mo

Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Kazuyuki*; Kawabata, Masako*; Minato, Futoshi; Saeki, Hideya*; Motoishi, Shoji*; Ito, Masatoshi*

Journal of the Physical Society of Japan, 87(4), p.043201_1 - 043201_5, 2018/04

 Times Cited Count:7 Percentile:63.33(Physics, Multidisciplinary)

Journal Articles

SPECT imaging of mice with $$^{99m}$$Tc-radiopharmaceuticals obtained from $$^{99}$$Mo produced by $$^{100}$$Mo(n,2n)$$^{99}$$Mo and fission of $$^{235}$$U

Hashimoto, Kazuyuki; Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi*; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji*; Ota, Masayuki; Konno, Chikara; Ochiai, Kentaro; et al.

Journal of the Physical Society of Japan, 84(4), p.043202_1 - 043202_4, 2015/04

 Times Cited Count:6 Percentile:50.68(Physics, Multidisciplinary)

Journal Articles

New phenomenon observed in thermal release of $$^{99m}$$Tc from molten $$^{100}$$MoO$$_{3}$$

Kawabata, Masako; Nagai, Yasuki; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*; Sato, Nozomi*; Ota, Akio*; Shiina, Takayuki*; Kawauchi, Yukimasa*

Journal of the Physical Society of Japan, 84(2), p.023201_1 - 023201_4, 2015/02

 Times Cited Count:6 Percentile:50.68(Physics, Multidisciplinary)

$$^{99m}$$Tc for medical use can be separated by thermochromatography from a molten $$^{99}$$MoO$$_{3}$$ sample. Effect of moist oxygen gas on the $$^{99m}$$Tc release from molten $$^{99}$$MoO$$_{3}$$ samples was investigated using a $$^{99}$$Mo/$$^{99m}$$Tc generator. $$^{99}$$Mo was produced with $$^{100}$$Mo(n,2n)$$^{99}$$Mo. A new phenomenon has been observed: release rate, separation- and recovery-efficiencies of $$^{99m}$$Tc were higher in the moist oxygen gas than those in the dry oxygen gas. The present result is a significant progress towards the stable production of a high quality $$^{99m}$$Tc from a molten MoO$$_{3}$$ sample with high separation efficiency. The result would also give us a new insight into the interaction between the moist oxygen gas and the molten MoO$$_{3}$$.

Journal Articles

High thermo-separation efficiency of $$^{99m}$$Tc from molten $$^{100}$$MoO$$_{3}$$ samples by repeated milking tests

Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*

Journal of the Physical Society of Japan, 83(8), p.083201_1 - 083201_4, 2014/07

 Times Cited Count:10 Percentile:62.33(Physics, Multidisciplinary)

Journal Articles

Generation of radioisotopes with accelerator neutrons by deuterons

Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sonoda, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro*; Tsukada, Kazuaki; et al.

Journal of the Physical Society of Japan, 82(6), p.064201_1 - 064201_7, 2013/06

 Times Cited Count:38 Percentile:86.37(Physics, Multidisciplinary)

Journal Articles

Successful labeling of $$^{rm 99m}$$Tc-MDP using $$^{rm 99m}$$Tc separated from $$^{99}$$Mo produced by $$^{100}$$Mo($textit{n}$,2$textit{n}$)$$^{99}$$Mo

Nagai, Yasuki; Hatsukawa, Yuichi; Kin, Tadahiro; Hashimoto, Kazuyuki; Motoishi, Shoji; Konno, Chikara; Ochiai, Kentaro; Takakura, Kosuke; Sato, Yuichi*; Kawauchi, Yukimasa*; et al.

Journal of the Physical Society of Japan, 80(8), p.083201_1 - 083201_4, 2011/08

 Times Cited Count:12 Percentile:63.04(Physics, Multidisciplinary)

We have for the first time succeeded to separate $$^{rm 99m}$$Tc from a Mo oxide sample irradiated by accelerator neutrons, and to formulate $$^{rm 99m}$$Tc-methylene diphosphonate ($$^{rm 99m}$$Tc-MDP). $$^{99}$$Mo, the mother nuclide of $$^{rm 99m}$$Tc, was produced by the $$^{100}$$Mo($textit{n}$,2$textit{n}$)$$^{99}$$Mo reaction using about 14 MeV neutrons provided at the Fusion Neutronics Source of Japan Atomic Energy Agency. The $$^{rm 99m}$$Tc was separated from $$^{99}$$Mo by the sublimation method, and its radionuclide purity was confirmed to be higher than 99.99%. The labeling efficiency of $$^{rm 99m}$$Tc-MDP was shown to be higher than 99%. These values exceed the United States Pharmacopeia requirements for a fission product, $$^{99}$$Mo. Consequently, a $$^{rm 99m}$$Tc radiopharmaceutical preparation formed by using the mentioned $$^{99}$$Mo can be a promising substitute for the fission product $$^{99}$$Mo. A longstanding problem to ensure a reliable and constant supply of $$^{99}$$Mo in Japan can be partially mitigated.

Journal Articles

Application of PZC to $$^{188}$$W/$$^{188}$$Re generators

Matsuoka, Hiromitsu; Hashimoto, Kazuyuki; Hishinuma, Yukio*; Ishikawa, Koji*; Terunuma, Hitoshi*; Tatenuma, Katsuyoshi*; Uchida, Shoji*

Journal of Nuclear and Radiochemical Sciences, 6(3), p.189 - 191, 2005/12

Applicability of Mo adsorbent PZC(Poly Zirconium Compound) for $$^{188}$$W/$$^{188}$$Re generator was investigated. Long term stability of adsorption of $$^{188}$$W to the PZC column, elution of $$^{188}$$Re from PZC column, desorption of $$^{188W}$$ from PZC column, and labeling of Hydroxyethylidene Diphosphonic Acid(HEDP) and Mercaptoacetyltriglycine(MAG3) with $$^{188}$$Re eluted from PZC column were tested. The PZC generator gave reproducible $$^{188}$$Re elution yields with low $$^{188}$$W parent breakthrough for a long period of time(about 5 months), that is the $$^{188}$$W/$$^{188}$$Re generator using PZC has a potential for practical use.

Journal Articles

${it Trans}$-1,2-dichloroethylene decomposition in low-humidity air under electron beam irradiation

Sun, Y.*; Hakoda, Teruyuki; Chmielewski, A. G.*; Hashimoto, Shoji*

Radiation Physics and Chemistry, 68(5), p.843 - 850, 2003/12

 Times Cited Count:7 Percentile:47.54(Chemistry, Physical)

no abstracts in English

Journal Articles

In vivo recognition of Cyclopentadienyltricarbonylrhenium (CpTR) derivatives

Uehara, Tomoya*; Koike, Miho*; Nakata, Hideo*; Miyamoto, Shigehiko*; Motoishi, Shoji; Hashimoto, Kazuyuki; Oku, Naoto*; Nakayama, Morio*; Arano, Yasushi*

Nuclear Medicine and Biology, 30(3), p.327 - 334, 2003/04

 Times Cited Count:20 Percentile:52.09(Radiology, Nuclear Medicine & Medical Imaging)

no abstracts in English

Journal Articles

Production of no-carrier-added $$^{177}$$Lu via the $$^{176}$$Yb(n,$$gamma$$)$$^{177}$$Yb$$rightarrow$$$$^{177}$$Lu process

Hashimoto, Kazuyuki; Matsuoka, Hiromitsu; Uchida, Shoji*

Journal of Radioanalytical and Nuclear Chemistry, 255(3), p.575 - 579, 2003/03

 Times Cited Count:32 Percentile:88.84(Chemistry, Analytical)

The $$beta^{-}$$ emitter $$^{177}$$Lu is a promising therapeutic radioisotope for the treatment of cancer. It has a half-life of 6.73 days and maximum $$beta^{-}$$ energy of 498 keV, resulting in a short range of radiation in tissue. The decay is accompanied by the emission of low energy $$gamma$$-radiation with $$E_{gamma}$$ = 208 keV (11.0%) and 113 keV (6.4%) suitable for simultaneous imaging. Lutetium-177 can be usually produced at nuclear reactors with high yield and high specific radioactivity by the $$^{176}$$Lu(n,$$gamma$$)$$^{177}$$Lu reaction. However, radioisotopes with higher specific radioactivity are required in the field of radioimmunotherapy using labeled monoclonal antibodies. Thus, an alternative production route, namely the $$^{176}$$Yb(n,$$gamma$$)$$^{177}$$Yb $$rightarrow$$ $$^{177}$$Lu process was studied to produce no-carrier-added (nca) $$^{177}$$Lu in this work. The radiochemical separation of the nca $$^{177}$$Lu from the macroscopic ytterbium target was investigated by means of reversed-phase ion-pair HPLC. The nca $$^{177}$$Lu was obtained in radiochemical pure form with a separation yield of 80%.

Journal Articles

Yields of primary products from chloroethylenes in air under electron beam irradiation

Hakoda, Teruyuki; Hashimoto, Shoji*; Kojima, Takuji

Proceedings of 9th International Conference on Radiation Curing (RadTech Asia '03) (CD-ROM), 4 Pages, 2003/00

no abstracts in English

Journal Articles

Electron-beam decomposition of vaporized VOCs in air

Hirota, Koichi; Hakoda, Teruyuki; Arai, Hidehiko; Hashimoto, Shoji

Radiation Physics and Chemistry, 65(4-5), p.415 - 421, 2002/11

 Times Cited Count:24 Percentile:82.32(Chemistry, Physical)

no abstracts in English

Journal Articles

Effect of water and oxygen contents on the decomposition of gaseous trichloroethylene in air under electron beam irradiation

Hakoda, Teruyuki; Hashimoto, Shoji; Kojima, Takuji

Bulletin of the Chemical Society of Japan, 75(10), p.2177 - 2183, 2002/10

 Times Cited Count:7 Percentile:35.05(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Transfer function analysis of positron-emitting tracer imaging system (PETIS) data

Keutgen, N.; Matsuhashi, Shimpei; Mizuniwa, Chizuko; Ito, Takehito*; Fujimura, Takashi; Ishioka, Noriko; Watanabe, Satoshi; Sekine, Toshiaki; Uchida, Hiroshi*; Hashimoto, Shoji

Applied Radiation and Isotopes, 57(2), p.225 - 233, 2002/09

 Times Cited Count:9 Percentile:53.47(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Desulfurization reaction of high sulfur content flue gas treated by electron beam

Hirosawa, Shojiro*; Kojima, Takuji; Hashimoto, Shoji; Suzuki, Ryoji*; Aoki, Shinji*

Radioisotopes, 51(8), p.285 - 295, 2002/08

Experiments of flue gas treatment by electron beam were carried out, using simulated lignite-burning flue gas containing SO$$_{2}$$(5500ppm), NO(390ppm) and H$$_{2}$$O(22%). Removal efficiency of SO$$_{2}$$ was more than 90% at a dose of 1-2kGy. It shows applicability of electron beam for treatment of lignite-burning flue gas. Another removal reaction besides the radiation-induced radical reaction and the thermal reaction occurring without irradiation was suggested by the facts that removal of SO$$_{2}$$ by the radical reaction is only a few hundreds of ppm and the removal amounts by thermal reaction under irradiation is lower than a half of total desulfurization. The mechanism similar to thermal reaction was proposed, assuming simultaneous uptake reaction of SO$$_{2}$$ and NH$$_{3}$$ on the surface of liquid aerosol. It was suggested that ammonium nitrate having deliquescence relative humidity(DRH) of 60% at 25$$^{circ}C$$ plays an important role in producing liquid aerosols. Decrease of DRH of ammonium nitrate with increasing temperature and with formation of double salt of ammonium sulfate results in enhancement of formation of liquid aerosols.

108 (Records 1-20 displayed on this page)