Neutron/-ray discrimination based on the property and thickness controls of scintillators using Li glass and LiCAF(Ce) in a -ray field

Kaburagi, Masaaki; Shimazoe, Kenji*; Terasaka, Yuta; Tomita, Hideki*; Yoshihashi, Sachiko*; Yamazaki, Atsushi*; Uritani, Akira*; Takahashi, Hiroyuki*

Nuclear Instruments and Methods in Physics Research A, 1046, p.167636_1 - 167636_8, 2023/01

https://doi.org/10.1016/j.nima.2022.167636

We focus on the thickness and property controls of inorganic scintillators used for thermal neutron detection in intense -ray fields without considering pulse shape discrimination techniques. GS20 (a lithium glass) and LiCaAlF:Ce(LiCAF:Ce) cintillators with thicknesses of 0.5 and 1.0 mm, respectively, have been employed. Pulse signals generated by photomultiplier tubes, to which the scintillators were coupled, were inserted into a digital pulse processing unit with 1 Gsps, and the areas of waveforms were integrated for 360 ns. In a Co -ray field, the neutron detection for GS20 with a 0.5-mm thickness was possible at dose rates of up to 0.919 Gy/h; however, for LiCAF:Ce, neutron detection was possible at 0.473 Gy/h, and it failed at 0.709 Gy/h. Threfore, in a Co -ray field, the neutron/-ray discrimination of GS20 was better than that of LiCAF:Ce due to its better energy resolution and higher detection efficiency.

Determination of emission rates and spectra of neutrons from Am-Li sources

Hoshi, Katsuya; Nishino, Sho; Yoshida, Tadayoshi; Tsujimura, Norio

JPS Conference Proceedings (Internet), 24, p.011020_1 - 011020_6, 2019/01

https://doi.org/10.7566/JPSCP.24.011020

We studied the application of AmLi interrogation neutron sources, which originally deployed in non-destructive assay apparatus for nuclear safeguard, to calibration work. To determine the emission rate, the angular distribution of neutron fluence was measured by a potable long counter. The emission rate at the date of measurement (October 23rd, 2015) was determined to be 1.0010 n/s (4.1% ( = 2)).

Socio-economic effects of the material science in JAERI

Yanagisawa, Kazuaki; Takahashi, Shoji*

Scientometrics, 78(3), p.505 - 524, 2008/10

https://doi.org/10.1007/s11192-008-1636-4

A socio-economic evaluation of Material Science (MS) of JAERI was made. The goal was to reveal the emphasized basic research fields (EBRF) of MS and to observe its socio-economic networking. High ranked keywords for the former and the number of co-authored papers for the latter were used along with many MS related papers. The obtained results are: (1) The EBRF of MS of JAERI were typically represented by the keywords of ion irradiation, actinides, etc., i.e., those having a strong relation to the nuclear field. Regarding actinides, the socio-economic networking between JAERI and PS occurred at the growth rate of 3-4% per 25 years, but 8% during the past 5 years. This implies that the research cooperation between the two was markedly enhanced. (2) The EBRF of MS between JAERI and 5 selected research bodies (SRB) represented by Tokyo University was directly compared and revealed that only 7 keywords as typically represented by neutron and accelerators. After overlapping, JAERI and SRB seem to be raising the national standard level.

Application of invasion mathematical model in dosimetry for boron neutron capture therapy for malignant glioma

Yamamoto, Kazuyoshi; Kumada, Hiroaki; Nakai, Kei*; Endo, Kiyoshi*; Yamamoto, Tetsuya*; Matsumura, Akira*

Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 14 Pages, 2004/10

A dose distribution considered the tumor cell density distribution is required on the radiation therapy. We propose a novel method of determining target region considering the tumor cell concentration as a new function for the next generation Boron Neutron Capture Therapy (BNCT) dosimetry system. It has not been able to sufficiently define the degree of microscopic diffuse invasion of the tumor cells peripheral to a tumor bulk in malignant glioma using current medical imaging. Referring to treatment protocol of BNCT, the target region surrounding the tumor bulk has been set as the region which expands at the optional distance with usual 2cm margin from the region enhanced on T1 weighted gadolinium Magnetic Resonance Imaging (MRI). In this research, the cell concentration of the region boundary of the target was discussed by using tumor cell diffusion model in the sphere spatio-temporal system. The survival tumor cell density distribution after the BNCT irradiation was predicted by the two regions diffusion model for a virtual brain phantom.

Conceptual design of spectrum changeable neutron calibration fields in JAERI/FRS

Saegusa, Jun; Tanimura, Yoshihiko; Yoshizawa, Michio; Yoshida, Makoto

Radiation Protection Dosimetry, 110(1-4), p.91 - 95, 2004/09

https://doi.org/10.1093/rpd/nch196

For the accurate estimation of neutron dose equivalents, it is important to calibrate dosemeters in the field whose energy spectrum is similar to that in the workplace. For the purpose, studies are made toward the built of the spectrum changeable neutron calibration fields with the Van-de-Graff accelerator in the FRS in JAERI. The fields are produced by bombarding proton or deuteron beam from the accelerator to suitable targets surrounded by quasi-cylindrical moderators and absorbers of various materials. In the fields, neutron spectra with wide range energy index should be provided with sufficient fluence rate for the calibration of dosemeters. The objectives and conceptual design of the fields are discussed here, followed by the test simulation results of neutron spectra produced by various arrangements of a target and moderators.

Construction of 144, 565 keV and 5.0 MeV monoenergetic neutron calibration fields at JAERI

Tanimura, Yoshihiko; Yoshizawa, Michio; Saegusa, Jun; Fujii, Katsutoshi; Shimizu, Shigeru; Yoshida, Makoto; Shibata, Yasunari*; Uritani, Akira*; Kudo, Katsuhisa*

Radiation Protection Dosimetry, 110(1-4), p.85 - 89, 2004/09

https://doi.org/10.1093/rpd/nch197

Mono-energetic neutron calibration fields have been developed at the Facility of Radiation Standards (FRS) of JAERI using 4MV Van-de-Graaff (Pelletron) accelerator. The fields of 144 keV, 565 keV and 5.0 MeV neutrons were constructed with estimating neutron energy spectra and establishing the traceability of reference neutron fluence.

Proceedings of the 3rd Workshop on Dosimetry for External Radiations; November 28-29, 2002, Japan Atomic Energy Research Institute, Tokai, Ibaraki, Japan

Yoshizawa, Michio; Endo, Akira

JAERI-Conf 2003-002, 166 Pages, 2003/03

JAERI-Conf-2003-002.pdf:9.79MB

The present report is Proceedings of the Third Workshop on Dosimetry for External Radiations, held at the Tokai Research Establishment, Japan Atomic Energy Research Institute (JAERI), in November 28-29, 2002. The proceedings comprises 16 papers and a summary of general discussion. The Third Workshop, subtitled "On an opportunity of the completion of the facility of calibration standards for neutron at JAERI", focused on neutron dosimetry and included presentations on the status of international neutron standards, the development of calibration techniques of neutron dosimeters using accelerator neutron sources, and dosimetry for high-energy neutrons. The workshop identified the directions for the future research and development in this field.

Integral test of JENDL Dosimetry File 99 with high flux neutron field

Shimakawa, Satoshi

JAERI-Data/Code 99-043, p.75 - 0, 1999/09

JAERI-Data-Code-99-043.pdf:3.38MB

no abstracts in English

A Study on various neutron standard fields for workplace

Asano, Yoshihiro

JAERI-Research 99-045, 105 Pages, 1999/08

JAERI-Research-99-045.pdf:3.56MB

no abstracts in English

Development of Pure Thermal Neutron Irradiation Facility in JRR-4 -Neutronics Calculation for the Design-

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JAERI-M 85-206, 60 Pages, 1985/12

JAERI-M-85-206.pdf:1.35MB

no abstracts in English