Application of the spectral determination method to unified -, - and X-ray spectra

Oshima, Masumi*; Goto, Jun*; Hayakawa, Takehito*; Asai, Masato; Shinohara, Hirofumi*; Suzuki, Katsuyuki*; Shen, H.*

Journal of Nuclear Science and Technology, 10 Pages, 2025/00

https://doi.org/10.1080/00223131.2024.2439921

The spectrum determination method (SDM) is the method to determine radioactivities by analyzing full spectral shape of - or rays through least-squares fitting by referring to standard - and spectra. In this paper, we have newly applied the SDM to a unified spectrum composed of two spectra measured with a Ge detector and a liquid scintillation counter. By analyzing the unified spectrum, uncertainties of deduced radioactivities have been improved. We applied this method to the unified spectrum including 40 radionuclides with equal intensities, and have deduced their radioactivities correctly.

Rapid multi-nuclide identification method by simultaneous , , and X-ray spectrum analysis

Oshima, Masumi*; Goto, Jun*; Hayakawa, Takehito*; Asai, Masato; Kin, Tadahiro*; Shinohara, Hirofumi*

Isotope News, (790), p.19 - 23, 2023/12

When analyzing samples that contain many radionuclides at various concentrations, such as radioactive waste or fuel debris, it is difficult to apply general spectrum analysis methods and is necessary to chemically separate each nuclide before quantifying it. The chemical separation is especially essential for analysis using a liquid scintillation counter (LSC). In this report, the authors explain the newly developed spectral determination method (SDM) in which the entire spectrum is fitted to quantify radioactivity of nuclides mixed in a sample. By applying the SDM to - and X-ray spectrum measured by LSC and -ray spectrum measured by Ge detector simultaneously, the authors demonstrated that radioactivity of 40 radionuclides mixed in a sample at concentrations varying by two orders could be quantified, which is useful to simplify chemical separation process in radionuclide quantification.

Rational evaluation of the therapeutic effect and dosimetry of auger electrons for radionuclide therapy in a cell culture model

Shinohara, Ayaka*; Hanaoka, Hirofumi*; Sakashita, Tetsuya*; Sato, Tatsuhiko; Yamaguchi, Aiko*; Ishioka, Noriko*; Tsushima, Yoshito*

Annals of Nuclear Medicine, 32(2), p.114 - 122, 2018/02

https://doi.org/10.1007/s12149-017-1225-9

Radionuclide therapy with low-energy auger electron emitters could potentially provide high anti-tumor efficacy while keeping normal organs toxicity low. In this study, we evaluated the usefulness of auger electron emitter I and compared it with beta-emitter I for tumor treatment in 2D and 3D cell culture models. The computer simulation model for 2D and 3D cell culture were constructed, and the absorbed radiation dose of I or I in each model were calculated by using a Monte Carlo simulation code (PHITS). The therapeutic effect of I was comparable to that of I in 2D model, but the efficacy was inferior to that of I-MIBG in 3D model, since crossfire effect is negligible and the homogeneous distribution of radionuclide was insufficient.

Report of investigation on malfunction of reserved shutdown system in HTTR

Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.

JAEA-Technology 2006-030, 58 Pages, 2006/03

JAEA-Technology-2006-030.pdf:10.69MB

During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert BC/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of BC/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.

New technique for the determination of trace elements using multiparameter coincidence spectrometry

Hatsukawa, Yuichi; Toh, Yosuke; Oshima, Masumi; Hayakawa, Takehito; Shinohara, Nobuo; Kushita, Kohei; Ueno, Takashi; Toyoda, Kazuhiro*

Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.111 - 113, 2003/01

https://doi.org/10.1023/A:1022287900085

no abstracts in English

Isotopic ratio of I/I in seaweed measured by neutron activation analysis with - coincidence

Toh, Yosuke; Hatsukawa, Yuichi; Oshima, Masumi; Shinohara, Nobuo; Hayakawa, Takehito; Kushita, Kohei; Ueno, Takashi

Health Physics, 83(1), p.110 - 113, 2002/07

https://doi.org/10.1097/00004032-200207000-00013

no abstracts in English

Application of multiparameter coincidence spectrometry using a Ge detectors array to neutron activation analysis

Hatsukawa, Yuichi; Oshima, Masumi; Hayakawa, Takehito; Toh, Yosuke; Shinohara, Nobuo

Nuclear Instruments and Methods in Physics Research A, 482(1-2), p.328 - 333, 2002/04

https://doi.org/10.1016/S0168-9002(01)01510-8

no abstracts in English

Improvement of neutron activation analysis due to coincident -ray detection

Oshima, Masumi; Hatsukawa, Yuichi; Toh, Yosuke; Hayakawa, Takehito; Shinohara, Nobuo

Kagaku To Kyoiku, 49(9), p.552 - 553, 2001/09

https://ci.nii.ac.jp/naid/110008592462

no abstracts in English

Measurement of long-lived nuclides by multi- ray analysis

Hatsukawa, Yuichi; Toh, Yosuke; Oshima, Masumi; Hayakawa, Takehito; Shinohara, Nobuo; Kushita, Kohei; Ueno, Takashi

KEK Proceedings 2001-14, p.193 - 194, 2001/06

no abstracts in English

A High-sensitivity, non-destructive trace element analysis

Oshima, Masumi; Toh, Yosuke; Hayakawa, Takehito; Hatsukawa, Yuichi; Shinohara, Nobuo

JAERI-Conf 2001-002, p.532 - 534, 2001/03

https://jopss.jaea.go.jp/pdfdata/JAERI-Conf-2001-002-Part1.pdf

no abstracts in English