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Journal Articles

True coincidence summing correction for cylindrical volume samples in $$gamma$$-ray spectrometry

Yamada, Takashi*; Asai, Masato; Yonezawa, Chushiro*; Kakita, Kazutoshi*; Hirai, Shoji*

Radioisotopes, 69(9), p.287 - 297, 2020/09

We have confirmed that the commercially available Japanese `standard' gamma-ray analysis programs do not consider the effect of sample volume in calculating true coincidence summing (TCS) corrections, which results in underestimation of $$^{134}$$Cs radioactivity in cylindrical volume samples. In this work, we have developed and examined a practical TCS correction method for general Ge detectors which consider the effect of sample volume properly, and have confirmed that this method can reduce the $$^{134}$$Cs radioactivity underestimation to less than 1%.

JAEA Reports

Development of measurement system of radioactive plume using unmanned airplane in the fiscal year 2018 (Contract research)

Sanada, Yukihisa; Ochi, Kotaro; Ishizaki, Azusa

JAEA-Research 2020-006, 60 Pages, 2020/07

JAEA-Research-2020-006.pdf:4.84MB

At the accident of nuclear facilities, a prediction of the behavior of released radioactive plume is indispensable to make a decision on a refuge plan of inhabitants. Currently, prediction system which is based on atmospheric dispersion simulation has been implemented as a tool of the atomic energy disaster prevention. However, the direct measurement method of the radioactive plume has not existed. In this study, some component technologies were developed for the establishment of direct measurement methods of radioactive plume using unmanned aerial vehicle whose technological innovation is remarkable. In addition, the spray test using mock aerosol was conducted to obtaining the deposition rate to the airplane body. The algorism of making a flight plan was developed based on a prediction model of the radioactive plume. This report summarized the outcome of the last year of the three-year plan.

JAEA Reports

Development of measurement system of radioactive plume using unmanned airplane in the fiscal year 2017 (Contract research)

Sanada, Yukihisa; Nishizawa, Yukiyasu*; Ochi, Kotaro; Yuki, Yoichi*; Ishizaki, Azusa; Osada, Naoyuki*

JAEA-Research 2018-009, 48 Pages, 2019/01

JAEA-Research-2018-009.pdf:14.77MB

At the accident of nuclear facilities, a prediction of the behavior of released radioactive plume is indispensable to make a decision on a refuge plan of inhabitants. Currently, prediction system which is based on atmospheric dispersion simulation has been implemented as a tool of the atomic energy disaster prevention. However, the direct measurement method of the radioactive plume has not existed. In this study, some component technologies were developed for the establishment of direct measurement methods of radioactive plume using unmanned aerial vehicle whose technological innovation is remarkable. In addition, the spray test using mock aerosol was conducted to obtaining the deposition rate to the airplane body. The algorism of making a flight plan was developed based on a prediction model of the radioactive plume. This report summarized the outcome of the second year of the three-year plan.

Journal Articles

$$alpha$$-decay study of $$^{182,184}$$Tl

Van Beveren, C.*; Andreyev, A.; Barzakh, A. E.*; Cocolios, T. E.*; de Groote, R. P.*; Fedorov, D.*; Fedosseev, V. N.*; Ferrer, R.*; Ghys, L.*; Huyse, M.*; et al.

Journal of Physics G; Nuclear and Particle Physics, 43(2), p.025102_1 - 025102_22, 2016/02

 Times Cited Count:11 Percentile:71(Physics, Nuclear)

Journal Articles

Nuclear structure of elements with $$100 le Z le 109$$ from alpha spectroscopy

Asai, Masato; He${ss}$berger, F. P.*; Lopez-Martens, A.*

Nuclear Physics A, 944, p.308 - 332, 2015/12

 Times Cited Count:39 Percentile:94.56(Physics, Nuclear)

Nuclear structure of Z = 100-109 nuclei studied through $$alpha$$-decay spectroscopy have been reviewed. Experimental techniques and methods concerning separation techniques, summing effects in $$alpha$$ spectra, and the use of digital electronics for $$alpha$$-decay spectroscopy have been described in detail. The presentation of the experimental results and the physics discussion were focused on nuclear structure systematics in even-Z nuclei along the N = 151, 153, and 155 isotonic lines, where most progress has been achieved in the last 10 years.

JAEA Reports

Essentials of neutron multiplicity counting mathematics; An Example of U-Pu mixed dioxide

Hosoma, Takashi

JAEA-Research 2015-009, 162 Pages, 2015/08

JAEA-Research-2015-009.pdf:22.3MB

Neutron coincidence counting assay systems have been developed in the last two decades. Objects would extend to high-mass uranium-plutonium dioxide containing other spontaneous fission nuclei, so essentials of neutron multiplicity counting were reconsidered and expanded: (a) Formulae of multiplicity distribution were algebraically derived up to septuplet using a probability generating function; (b) Leakage multiplication was evaluated not by Monte Carlo method but by an average length from an arbitrary point inside a sample to an arbitrary point on its surface and a probability of induced fission within the length; (c) Mechanism of coincidence counting was associated with a couple of different time axes in Poisson process, and consequently a pair of close-to-coincident neutrons from the process was derived. For the formulae, new expressions using combination were wrote down. For spectrum and mean free path, actually treated uranium-plutonium dioxide was selected as an example.

Journal Articles

First $$alpha$$-$$gamma$$ spectroscopy using Si-Ge detector array installed at focal plane of GARIS

Kaji, Daiya*; Morimoto, Koji*; Wakabayashi, Yasuo*; Takeyama, Mirei*; Asai, Masato

JPS Conference Proceedings (Internet), 6, p.030106_1 - 030106_4, 2015/06

A Si-Ge detector array was newly installed at the focal plane of the gas-filled recoil ion separator GARIS to perform $$alpha$$-$$gamma$$ (X-rays) spectroscopy for superheavy nuclei. The performance of the array was tested using the $$^{207}$$Pb($$^{48}$$Ca,2n)$$^{253}$$No and $$^{208}$$Pb($$^{48}$$Ca,xn)$$^{256-x}$$No [x=1,2,3] reactions. $$gamma$$ rays originating from the $$alpha$$ decay of $$^{253}$$No and $$^{255}$$No were clearly observed in prompt coincidence with the $$alpha$$ particles.

JAEA Reports

Study on coincidence and anti-coincidence $$gamma$$-ray spectrometry for the rapid radioactivity evaluation of solidified products prepared from radioactive wastes

Haraga, Tomoko; Kameo, Yutaka; Hoshi, Akiko; Yonezawa, Chushiro*; Nakashima, Mikio

JAERI-Tech 2005-050, 35 Pages, 2005/09

JAERI-Tech-2005-050.pdf:1.35MB

Non-destructive $$gamma$$-ray spectrometry has been examined as a simple and rapid radioactivity measurement technique for the solidified products prepared by plasma melting for low level radioactive miscellaneous wastes generated from nuclear facilities. The Compton background resulting from the coexisting radionuclides pose a problem in the usual $$gamma$$-ray spectrometry which uses only a Ge detector. In order to reduce the background count and to measure the interested nuclide selectively, the coincidence and the anti-coincidence $$gamma$$-ray spectrometry using the Ge-BGO detector system were examined. As a result of applying the anti-coincidence $$gamma$$-ray spectrometry to a single $$gamma$$-ray emitter $$^{137}$$Cs and the coincidence $$gamma$$-ray spectrometry to multiple $$gamma$$-ray emitter $$^{152}$$Eu under existence of $$^{60}$$Co, the detection limits of $$^{137}$$Cs and $$^{152}$$Eu in the sample, which contained $$^{60}$$Co, were reduced by a factor of about 6 and 1.5, respectively. It was confirmed that the present methods are useful for the $$gamma$$-activity measurement of solidified products.

JAEA Reports

Characteristics of 64 $$times$$ 64 channel high-position resolution neutron imaging detector

Sakasai, Kaoru; Katagiri, Masaki; Matsubayashi, Masahito; Rhodes, N.*; Schoonveld, E.*

JAERI-Research 2004-020, 19 Pages, 2004/12

JAERI-Research-2004-020.pdf:4.57MB

no abstracts in English

Journal Articles

Calibration of epithermal neutron beam intensity for dosimetry at JRR-4

Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Torii, Yoshiya; Sakurai, Yoshinori*; Kobayashi, Toru*

Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 15 Pages, 2004/10

To carry out the boron neutron capture therapy (BNCT) using the epithermal neutron, the epithermal neutron beam intensity was measured by using $$^{197}$$Au reaction rate activated on the resonance absorption peak (4.9eV). Two scaling factors, which are the reactor power calibration factor and the calculation/experiment (C/E) scaling factor, are necessary in order to correct with the simulation and actual irradiation experiment. First, an optimum detector position was investigated using MCNP code. The result of MCNP calculation showed that the influence of subject placed at the collimator was below 1% when the detector was placed in the distance of over 20cm from the collimator. Therefore we installed the monitor holders near the bismuth block in order to set three gold wire monitors. The factors were determined in the calibration experiments that measure the thermal neutron flux in the phantom and reaction rate of the gold wire monitors. The monitoring technique to measure epithermal neutron beam intensity was applied to clinical irradiation with the epithermal neutron beam.

Journal Articles

Analysis of time evolution of neutron intensity measured with a high-sensitive neutron collar during the JCO criticality accident

Endo, Akira; Yamaguchi, Yasuhiro; Sumita, Kenji*

Journal of Nuclear Science and Technology, 40(8), p.628 - 630, 2003/08

 Times Cited Count:4 Percentile:32.68(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Two-dimensional neutron imaging method using scintillators with wavelength shifting fibers

To, Kentaro; Katagiri, Masaki; Sakasai, Kaoru; Matsubayashi, Masahito; Birumachi, Atsushi; Takahashi, Hiroyuki*; Nakazawa, Masaharu*

Nuclear Instruments and Methods in Physics Research A, 485(3), p.571 - 575, 2002/09

 Times Cited Count:2 Percentile:19.85(Instruments & Instrumentation)

no abstracts in English

JAEA Reports

Measurement of thermal neutron flux for BNCT in JRR-2

; Torii, Yoshiya; ; Ichimura, Shigeju; *; Sasajima, Fumio; *; *; *; Takahashi, Hidetake

JAERI-M 94-058, 45 Pages, 1994/03

JAERI-M-94-058.pdf:1.25MB

no abstracts in English

Journal Articles

Measurement of low level $$^{226}$$Ra and $$^{222}$$Rn in water and $$^{222}$$Rn in air by liquid scintillation counting techniques; Its practical applicability

Amano, Hikaru

Proc. of the 4th Int. Seminor of Liquid Scintillation Analysis, p.185 - 209, 1991/00

no abstracts in English

Journal Articles

Pre-scission $$^{4}$$He multiplicity in the $$^{19}$$F + $$^{197}$$Au reaction

Ikezoe, Hiroshi; Shikazono, Naomoto; Nagame, Yuichiro; Sugiyama, Yasuharu; Tomita, Yoshiaki; Ideno, K.; Iwamoto, Akira; *

Physical Review C, 42(1), p.342 - 353, 1990/07

 Times Cited Count:33 Percentile:85.91(Physics, Nuclear)

no abstracts in English

Journal Articles

Coincidence measurements of light particles and evaporation residues in the $$^{16}$$O + $$^{27}$$Al fusion reaction

; ; ; ;

Nuclear Physics A, 462, p.150 - 162, 1987/00

 Times Cited Count:11 Percentile:56.55(Physics, Nuclear)

no abstracts in English

JAEA Reports

Journal Articles

The Half-life of $$^{152}$$Eu

; ; ; ; ;

International Journal of Applied Radiation and Isotopes, 34(6), p.891 - 892, 1983/00

 Times Cited Count:2 Percentile:35.76(Nuclear Science & Technology)

no abstracts in English

Journal Articles

A Method for determination of the $$^{1}$$$$^{5}$$$$^{2}$$Eu activity

; ; ; ;

Nuclear Instruments and Methods, 203, p.273 - 280, 1982/00

no abstracts in English

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