External dose estimation for wild animals using ESR spectroscopy

Oka, Toshitaka; Takahashi, Atsushi*

Hoshasen Kagaku (Internet), (110), p.13 - 19, 2020/10

The article depicts how to estimate the external exposure dose for wild animals using electron spin resonance (ESR) spectroscopy. The relationship between the CO radical intensity and the absorbed dose, that is, dose response curve of tooth enamel of Japanese macaque was observed, and the detection limit of our method was estimated. The estimated detection limit of 33.5 mGy is comparable to the previously reported detection limit for human molar teeth. The external exposure dose for seven wild Japanese macaques captured in Fukushima prefecture were examined using this dose response curve. The estimated external exposure dose were ranged between 45 mGy to 300 mGy.

Solid parahydrogen and ESR

Kumada, Takayuki

Kagaku No Yoten Shirizu, 20, P. 71, 2017/06

no abstracts in English

Relaxation time of radiation-induced radicals in -ray irradiated amino acids

Nagata, Natsuki*; Komoda, Seiichi*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 103, 2016/02

https://doi.org/10.11484/jaea-review-2015-022

no abstracts in English

Dose responses of irradiated fresh papaya recorded on ESR at different temperature

Kikuchi, Masahiro; Ukai, Mitsuko*; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 89, 2015/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2014-050.pdf#page=121

Characterization of interface defects related to negative-bias temperature instability in ultrathin plasma-nitrided SiON/Si100 systems

Fujieda, Shinji*; Miura, Yoshinao*; Saito, Motofumi*; Teraoka, Yuden; Yoshigoe, Akitaka

Microelectronics Reliability, 45(1), p.57 - 64, 2005/01

https://doi.org/10.1016/j.microrel.2004.02.017

To characterize the interface defects that are responsible for the negative-bias temperature instability (NBTI) of a thin plasma-nitrided SiON/Si system, we carried out inerface trap density measurements, electron-spin resonance spectroscopy and synchrotron radiation XPS. The NBTI was shown to occur mainly through the dehydrogenation of the interfacial Si dangling bonds (P defects). Although we suggest that non- P defects are also generated by the negative-bias temperature stress, nitrogen dangling bonds do not seem to be included. The plasma-nitridation process was confirmed to generate sub-oxides at the interface and thus increase the interface trap density. Furthermore, it was found that the nitridation induces another type of P defect than that at pure-SiO/Si interfacec. Such an increase and structural change of the interfacial defects are likely the causes of the nitridation-enhanced NBTI.

Introduction of phosphorus atoms in silicon carbide using nuclear transmutation doping at elevated temperatures

Oshima, Takeshi; Morishita, Norio; Kamiya, Tomihiro; Isoya, Junichi*; Baba, Shinichi; Aihara, Jun; Yamaji, Masatoshi*; Ishihara, Masahiro

Proceedings of OECD/NEA 3rd Information Exchange Meeting on Basic Studies in the Field of High Temperature Engineering (OECD/NEA No.5309), p.197 - 202, 2004/00

For the application of SiC to electronic devices, it is necessary to develop the fabrication technique of high quality SiC substrates with uniform carrier concentration. Since phosphorus (P) atoms become shallow donors in SiC, nuclear transmutation doping (NTD) is thought to be a good method for the fabrication of n-type SiC substrates with uniform electron concentration. However, defects are also introduced in SiC by neutron irradiation. Although thermal annealing at high temperatures above 1500C is carried out to remove defects after irradiation, heavy damage in SiC is hard to recover. Therefore, the process for the reduction of defects in SiC irradiated with neutrons is necessary to develop. In this study, neutron irradiation into SiC at elevated temperature was carried out to decrease radiation damage. The electrical properties of the samples are studied using Hall effect measurement. Furthermore, to establish the measurement technique for the estimation of P atoms created in SiC by NTD, P atoms in SiC were investigated using Electron Spin Resonance (ESR).

ESR characterization of activation of implanted phosphorus ions in silicon carbide

Isoya, Junichi*; Oshima, Takeshi; Oi, Akihiko; Morishita, Norio; Ito, Hisayoshi

Nuclear Instruments and Methods in Physics Research B, 206, p.965 - 968, 2003/05

https://doi.org/10.1016/S0168-583X(03)00903-0

no abstracts in English

Analyses of absorbed dose to tooth enamel against external photon exposure

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Funabiki, Jun*; Saito, Kimiaki

Radiation Protection Dosimetry, 103(2), p.125 - 130, 2003/01

https://doi.org/10.1093/oxfordjournals.rpd.a006123

Absorbed dose to tooth enamels against external photon exposure was examined by the Electron Spin Resonance (ESR) dosimetry using tooth samples placed in a realistic physical phantom. Dose to teeth region was also measured with thermo-luminescence dosimeters (TLDs). A voxel-type phantom was constructed from CT images of the physical phantom. Monte Carlo calculations with this voxel-type phantom were performed to analyse the results of the experiments. The obtained data in this study were compared to the enamel doses, which were calculated with a modified MIRD-type and already given in a previous paper. The results suggested that the conversion factors from enamel dose to organ doses obtained by the modified MIRD-type phantom are to be applicable for retrospective individual dose assessments by the ESR dosimetry. The analysis, however, indicated that the size and figure of the head can affect the enamel dose for low photon energy region below 100keV.

Conversion from tooth enamel dose to organ doses for the electron spin resonance dosimetry

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Saito, Kimiaki

Journal of Nuclear Science and Technology, 39(9), p.964 - 971, 2002/09

https://doi.org/10.3327/jnst.39.964

Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by the Electron Spin Resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effects of human model on the tooth enamel dose with a voxel-type phantom, which was based on CT images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiations were taken into account. The results indicated that energy distribution of photons incident to a human body should be required to evaluate precisely individual dose by the ESR dosimetry using teeth.

A Model for the structure of the SOS-regulated UmuD protein

Sutton, M. D.*; Guzzo, A.*; Narumi, Issei; Costanzo, M.*; Altenbach, C.*; Ferentz, A. E.*; Hubbell, W. L.*; Walker, G. C.*

DNA Repair, 1(1), p.77 - 93, 2002/01

UmuD protein is a regulatory subunit of DNA polymerase V. This protein forms a complex with UmuC protein, a catalytic subunit of DNA polymerase V, and plays a important role in error-prone translesion DNA synthesis, which serves as the mechanistic basis for most DNA-damaging agent and UV light mutagenesis. In this paper, based on the results of a combination of experimental studies, we have developed a refined model for the structure of the UmuD homodimer. Implications of the structural change of UmuD protein with respect to its roles in managing the action of DNA polymease V are discussed.