A study on improvements in accuracy of nuclear data measurements using -ray spectroscopic methods

Furutaka, Kazuyoshi

JNC TN8400 2000-028, 70 Pages, 2000/10

JNC-TN8400-2000-028.pdf:1.71MB

This report describes the study done by the author as a postdoctoral research associate at Japan Nuclear Cycle Development Institute. This report is divided into two parts: improvements in accuracy in determination of thermal neutron capture cross sections, and improvements in accuracy of photo-nuclear absorption cross section measurements using the HHS. (1)In the measurements of thermal neutron capture cross sections using an activation method, accuracies of the final results attained are limited by (1) accuracy of -ray peak detection efficiencies, and (2) accuracies of -ray emission probabilities. In this study; to determine thermal neutron capture cross sections more accurately, the following researches have been done using a newly developed three-dimensional coincidence measurement system: (1)accurate determination of -ray standard sources using a - coincidence method, for precise calibration of -ray peak detection efficiency, and (2) development of a - coincidence measurement system using a plastic scintillation detector as a -ray detector, for the determination of -ray emission probabilities of short-lived nuclides, and measurement of -ray emission probabilities of Tc nuclide using the coincidence system. (2)To transform radioactive nuclides with small thermal neutron capture cross sections, use of photonuclear absorption reaction has been suggested. In order to transform these nuclides efficiently using the reaction, one has to know detailed behavior of the photo-absorption cross sections. In this study, a Monte-Carlo simulation code has been used to create a standard set of -ray response functions of the high-resolution high-energy spectrometer (HHS), to enable reliable analyses of the data obtained by the spectrometer.

Performance of a nuclear reactor cover-gas monitor using charcoal-Ge gamma-ray spectrometer combination

IEEE Transactions on Nuclear Science, NS-31(1), p.757 - 760, 1984/00

no abstracts in English

Fundamental study of fast high energy gamma-ray spectrometer

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

no journal, , 

https://f-archive.jaea.go.jp/dspace/handle/faa/184143

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.

Fabrication of 2-cm thick TlBr detectors

Hitomi, Keitaro*; Maeda, Shigetaka; Nogami, Mitsuhiro*; Ito, Chikara; Watanabe, Kenichi*

no journal, , 

A 2-cm thick pixelated TlBr detector was fabricated in this study. A 50-mm diameter TlBr crystal was grown by the Bridgman-Stockbarger method using zone-purified materials. A pixelated TlBr detector was fabricated from the grown crystal with the dimension of 20 mm 20 mm 20 mm. The planar cathode and pixelated anodes were constructed on the crystal by vacuum evaporation of Tl. The anode consisted of 16-pixel electrodes (3 mm 3 mm) surrounded by a guard ring. A charge-sensitive preamplifier was connected to a pixel electrode on the device. The output signals from the preamplifier were recorded with a digitizer. The acquired signal waveforms were analyzed with a PC event by event for obtaining pulse-height spectra. The cathode surface of the pixelated TlBr detector was irradiated with an Am-241 gamma-ray source at room temperature. The applied bias voltage to the cathode was 2000 V. A clear full-energy peak corresponding to 59.5-keV gamma rays was obtained from the detector. The clear full-energy peak of 59.5-keV gamma-ray was reflecting the good electron transport property of the TlBr crystal.