A Cubic CeBr gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power Station

Kaburagi, Masaaki; Shimazoe, Kenji*; Otaka, Yutaka*; Uenomachi, Mizuki*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.

Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08

https://doi.org/10.1016/j.nima.2020.164118

High pressure and high temperature EXAFS and diffraction study of AgI (MS35)

Yoshiasa, Akira*; Arima, Hiroshi; Fukui, Hiroshi*; Okube, Maki*; Katayama, Yoshinori; Otaka, Osamu*

Nihon Kessho Gakkai-Shi, 51(1), p.66 - 69, 2009/02

We have determined a precise P-T phase diagram of AgI by high-temperature high-pressure synchrotron experiments. X-ray diffraction and X-ray absorption measurements were performed using a multi-anvil high pressure apparatus at SPring-8 synchrotron radiation facility. In a disordered rock-salt phase, Ag ions occupy both octahedral and tetrahedral sites. The occupancy of tetrahedral site has a maximum value, 20%, at 2 GPa. A change from rock-salt structure to disordered rock-salt structure is gradual in the X-ray diffraction measurements while it is clearly observed in the X-ray absorption measurements. Analysis of EXAFS Debye-Waller factor is useful because the force constant can be decided directly even at high pressure and high temperature. Pressure influences greatly the effective potential and anharmonicity decreases with increasing pressure.

Rhemium-186-monoaminemonoamidedithiol-conjugated bisphosphonate derivatives for bone pain palliation

Ogawa, Kazuma*; Mukai, Takahiro*; Arano, Yasushi*; Otaka, Akira*; Ueda, Masashi*; Uehara, Tomoya*; Magata, Yasuhiro*; Hashimoto, Kazuyuki; Saji, Hideo*

Nuclear Medicine and Biology, 33(4), p.513 - 520, 2006/05

https://doi.org/10.1016/j.nucmedbio.2006.03.006

To develop a radiopharmaceutical for the palliation of painful bone metastases based on the concept of bifunctional radiopharmaceuticals, we synthesized a bisphosphonate derivative labeled with rhenium-186 (Re) that contains a hydroxyl group at the central carbon of its bisphosphonate structure and attached a stable Re-MAMA chelate to the amino group of a 4-amino-butylidene-bisphosphonate derivative, Re-MAMA-HBP, and investigated the effect of a hydroxyl group at the central carbon of its bisphosphonate structure on the affinity for hydroxyapatite and biodistribution by conducting a comparative study with Re-MAMA-BP. Re-MAMA-HBP was prepared by a reaction with ReO and SnCl in citrate buffer after the deprotection of trityl groups of Tr-MAMA-HBP. After reversed phase HPLC, Re-MAMA-HBP had a radiochemical purity of over 95 %. Compared with Re-MAMA-BP, Re-MAMA-HBP showed a greater affinity for hydroxyapatite beads in vitro and accumulated a significantly higher level in the femur in vivo. Thus, the introduction of a hydroxyl group into Re complex-conjugated bisphosphonates would be effective in enhancing accumulation in bone. These findings provide useful information on the design of bone-seeking therapeutic radiopharmaceuticals.

Anharmonicity of platinum under HP and HT

Okube, Maki*; Yoshiasa, Akira*; Otaka, Osamu*; Katayama, Yoshinori

High Pressure Research, 23(3), p.247 - 251, 2003/09

https://doi.org/10.1080/0895795032000102423

In order to examine the pressure effect on anharmonic thermal vibrations of Pt, Extended X-ray Absorption Fine Structure (EXAFS) spectra near Pt K-edge and L-edge were measured in the temperature range from 300 to 800K under pressures up to 6vGPa, using large volume high-pressure devices and synchrotron radiation. We have investigated the anharmonic interatomic potentials by a cumulant expansion method. The values of EXAFS Debye-Waller factors, 2 and 3, become smaller with increase of pressure. The anharmonic effective pair potential was evaluated and the potential coefficient a at 0.1MPa and 6GPa are 4.8 and 5.0eV/, respectively. The anharmonic potential parameter decreases with increasing pressure.

XAFS study of GeO glass under pressure

Otaka, Osamu*; Yoshiasa, Akira*; Fukui, Hiroyuki*; Murai, Keiichiro*; Okube, Maki*; Takebe, Hitoshi*; Katayama, Yoshinori; Utsumi, Wataru

Journal of Physics; Condensed Matter, 14(44), p.10521 - 10524, 2002/11

https://doi.org/10.1088/0953-8984/14/44/326

no abstracts in English

Anharmonicity of gold under high-pressure and high-temperature

Okube, Maki*; Yoshiasa, Akira*; Otaka, Osamu*; Fukui, Hiroshi*; Katayama, Yoshinori; Utsumi, Wataru

Solid State Communications, 121(5), p.235 - 239, 2002/02

https://doi.org/10.1016/S0038-1098(01)00494-X

In order to examine the pressure effect on the anharmonicity of Au, EXAFS spectra near Au -edge were measured at the temperature range from 300 to 1000K under pressure up to 14GPa using large volume high-pressure devices and synchrotron radiation. The values of EXAFS Debye-Waller factors, and , become smaller with increase of pressure, which indicates that the potential width become narrower with pressure. The anharmonic effective pair potentials of Au, , at 0.1MPa, 6 and 14GPa have been calculated. The pressure dependence of the coefficient of thermal expansion has also been evaluated.

Anharmonic effective pair potentials of and CuBr at high pressure

Yoshiasa, Akira*; Okube, Maki*; Otaka, Osamu*; Kamishima, Osamu*; Katayama, Yoshinori

Japanese Journal of Applied Physics, Part 1, 39(12A), p.6747 - 6751, 2000/12

https://doi.org/10.1143/JJAP.39.6747

The anharmonic effective pair potentials for Br-Cu bond in and CuBr under pressure have been investigated by an extended X-ray absorption fine structure (EXAFS) technique. The EXAFS spectra near the Br K-edge were measured under high temperature and high pressure using a large-volume uniaxial press and synchrotron radiation from SPring-8. The anharmonic effective pair potential for each phase is influenced by pressure and become steeper with increasing pressure. The potential parameter for -phase at 0.1MPa increases by about 20% at the pressure of 4.8GPa. The stastical distribution of Cu in -CuBr and superionic conduction mechanism have been discussed based on the effective pair potential and distribution of Br-Cu distances.

CeBr gamma-ray spectrometer toward the decommissioning of the Fukushima Daiichi Nuclear Power Station

Kaburagi, Masaaki; Shimazoe, Kenji*; Otaka, Yutaka*; Foong, W. S.*; Uenomachi, Mizuki*; Kamada, Kei*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.

no journal, , 

no abstracts in English

Performance study of multi cubic high energy -ray spectrometric system for the decommissioning of the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station

Kaburagi, Masaaki; Shimazoe, Kenji*; Otaka, Yutaka*; Uenomachi, Mizuki*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.

no journal, , 

The retrieval of the nuclear fuel debris, which is the substance including melted nuclear fuel and structural materials, will be started from fiscal 2021. Then, as a non-destructive analysis technology of the nuclear fuel debris, a -ray spectroscopy system is being developed to measure high energy rays due to Eu and nuclear reactions under high dose rate, which was composed of a CeBr cubic, photomultiplier tube, and fast signal processing unit. This presentation reports that the exposure study of the detector system was performed for a Co field at the dose rates of up to 750 mSv/h, and the detector response was investigated at each dose rate.