Faculty Profiles - YOSHIHASHI Sachiko

Papers - YOSHIHASHI Sachiko

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Thermal Neutron Measurement Capability of a Single Crystal CVD Diamond Detector near the Reactor Core Region of UTR-KINKI Open Access

KOBAYASHI Makoto I., YOSHIHASHI Sachiko, YAMANISHI Hirokuni, SANGAROON Siriyaporn, OGAWA Kunihiro, ISOBE Mitsutaka, URITANI Akira, OSAKABE Masaki

Plasma and Fusion Research Vol. 17 ( 0 ) page： 2405045 - 2405045 2022.6

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Plasma Science and Nuclear Fusion Research

Thermal neutron flux evaluation using a single crystal diamond detector (SDD) was carried out in the core region of the UTR-KINKI reactor where a mixed radiation field by thermal and fast neutrons and gamma-ray exists. The pulse shape discrimination method to extract pulses with a rectangular shape as well as a wide pulse-width was established to exclude pulses induced by gamma-rays. The SDD, using a 6LiF thermal neutron converter, is able to detect pulse events caused not only by fast neutrons but also by thermal neutrons through energy depositions into the diamond by energetic alpha and triton particles induced by thermal neutrons. Additionally, the SDD without the thermal neutron converter was used for the measurement of the energy deposition events only by fast neutrons. A comparison of the pulse counts of the SDD with or without the thermal neutron convertor deduced the energy deposition spectra by thermal neutrons. The thermal neutron flux in the core region of the UTR-KINKI reactor was evaluated to be 7.6×106 n cm−2 s−1 W−1 up to a reactor power of 1 W.

DOI： 10.1585/pfr.17.2405045

A comprehensive evaluation of the thermal neutron detection efficiency by a single crystal CVD diamond detector with a LiF thermal neutron converter Open Access

Kobayashi Makoto I, Yoshihashi Sachiko, Ogawa Kunihiro, Isobe Mitsutaka, Sangaroon Siriyaporn, Kamio Shuji, Fujiwara Yutaka, Osakabe Masaki

FUSION ENGINEERING AND DESIGN Vol. 179 2022.6

Neutron yield calculation of p-Li thick target by using PHITS with JENDL-4.0/HE and ENDF/B-VII for BNCT application

Nishitani Takeo, Tanagami Yuuki, Yoshihashi Sachiko, Tsuchida Kazuki, Yamazaki Atsushi, Uritani Akira

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY Vol. 59 ( 5 ) page： 605 - 613 2022.5

Neutron yield calculation of thin and thick d-D targets by using PHITS with frag data table Open Access

Takeo Nishitani, Sachiko Yoshihashi, Kunihiro Ogawa, Misako Miwa, Shigeo Matsuyama, Akira Uritani

Journal of Nuclear Science and Technology Vol. 59 ( 4 ) page： 534 - 541 2022.4

Evaluation of the thermal neutron sensitivity, output linearity, and gamma-ray response of optical fiber-based neutron detectors using Li-glass scintillator

Akihisa Ishikawa, Kenichi Watanabe, Atsushi Yamazaki, Sachiko Yoshihashi, Shigefumi Imai, Akihiko Masuda, Tetsuro Matsumoto, Hiroki Tanaka, Yoshinori Sakurai, Mitsuhiro Nogami, Keitaro Hitomi, Akira Uritani, Hideki Harano

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 1025 2022.2

Language：Japanese Publishing type：Research paper (scientific journal)

An optical fiber-based neutron detector can be used as a real-time neutron monitor for an intense neutron field. In this study, optical fiber-based neutron detectors were fabricated using Li-glass scintillator. The thermal neutron sensitivity, upper limit of the output linearity, and response to gamma rays from 60Co and Cd were evaluated. The thermal neutron sensitivity was proportional to the mass of the Li-glass scintillator, and the calibration factor was 2.06 × 10−6 and 3.18 × 10−6 cps/(n/cm 2/s)/μg for the lower-level discrimination of the peak and valley channel, respectively. The detector output linearity was confirmed to be up to nearly 2 Mcps. While evaluating the response to gamma rays, for both 60Co and Cd, the gamma-ray counting rate was found to be smaller than the uncertainty associated with counting statistics in most expected applications where the neutron counting rate was >1 kcps.

DOI： 10.1016/j.nima.2021.166074

Web of Science

Scopus

Benchmark Calculation of d-Li Thick Target Neutron Yield by JENDL/DEU-2020 for IFMIF and Similar Facilities Open Access

NISHITANI Takeo, YOSHIHASHI Sachiko, KUMAGAI Kohki, KONDO Keitaro, URITANI Akira

Plasma and Fusion Research Vol. 16 ( 0 ) page： 1405104 - 1405104 2021.11

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Plasma Science and Nuclear Fusion Research

An accelerator-based neutron source using d-Li reactions is one of the most promising neutron sources for fusion material irradiation facilities such as IFMIF, where 40 MeV deuterons bombard a liquid lithium target. The neutron yield estimation including angular neutron spectra is one of the most important issues in the design of such irradiation facilities. Recently, JAEA released deuteron nuclear data of JENDL/DEU-2020 in ACE format file for Monte Carlo codes such as MCNP, and in Frag-Data format for the PHITS code. We carry out the benchmark calculations of d-Li neutron yield by using PHITS with Frag-Data, MCNP with JENDL/DEU-2020, and MCNP/PHITS with built-in nuclear reaction models. Those calculation results are compared with experimental data. It is confirmed that PHITS with Frag Data and MCNP with JENDL/DEU-2020 reproduce well the experimental data. Those are useful for the neutron yield estimation and also the irradiation field characterization of IFMIF and similar facilities.

DOI： 10.1585/pfr.16.1405104

Gamma-ray Dosimetry in the BNCT Irradiation Field Using BeO Optically Stimulated Luminescence Dosimeter

Watanabe Kenichi, Nakamura Satoru, Nagasaka Kosei, Yamazaki Atsushi, Yoshihashi Sachiko, Uritani Akira

JSAP Annual Meetings Extended Abstracts Vol. 2021.1 ( 0 ) page： 576 - 576 2021.2

Gamma-ray Dosimetry in the BNCT Irradiation Field Using BeO Optically Stimulated Luminescence Dosimeter

Watanabe Kenichi, Nakamura Satoru, Nagasaka Kosei, Yamazaki Atsushi, Yoshihashi Sachiko, Uritani Akira

JSAP Annual Meetings Extended Abstracts Vol. 2021.1 ( 0 ) page： 576 - 576 2021.2

First experimental verification of the neutron field of Nagoya University Accelerator-driven neutron source for boron neutron capture therapy Open Access

Watanabe Kenichi, Yoshihashi Sachiko, Ishikawa Akihisa, Honda Shogo, Yamazaki Atsushi, Tsurita Yukio, Uritani Akira, Tsuchida Kazuki, Kiyanagi Yoshiaki

Applied Radiation and Isotopes Vol. 168 page： 109553 2021.2

Language：English Publishing type：Research paper (scientific journal)

As the commissioning phase of the Nagoya University Accelerator-driven Neutron Source for boron neutron capture therapy, in-phantom thermal neutron flux measurements were conducted using a small ^<6>LiF/Eu:CaF_2 scintillator detector and activation foils. The spatial distribution of the measured thermal neutron flux agreed with the Monte Carlo simulation results. Based on this comparison, the free-in-air neutron spectrum, calculated at the exit aperture, was verified and the epithermal neutron flux, at a 0.25 mA proton current, was evaluated as (1.49±0.10)×10^<7> n/(c㎡ s).

DOI： 10.1016/j.apradiso.2020.109553

Thermal neutron measurement by single crystal CVD diamond detector applied with the pulse shape discrimination during deuterium plasma experiment in LHD Open Access

Kobayashi M.I

Fusion Engineering and Design Vol. 161 2020.12

Language：Japanese Publishing type：Research paper (scientific journal)

The Pulse shape discrimination (PSD) technique for single crystal CVD diamond detector (SDD) was applied to the real-time thermal neutron measurement during the 3rd campaign of Deuterium-Deuterium (D-D) plasma experiment in the Large Helical Device (LHD). The PSD method is based upon the different shape of electrical pulses produced in diamond by gamma-ray (triangular-shaped pulse) and energetic ions (rectangular-shaped pulse), respectively. An improved PSD was developed which makes use of the full width at half maximum (FWHM) and the full width at 2/3 of the peak height (FW2/3 PH). These two parameters reflect the difference in the pulse shape produced by gamma-rays and energetic ions. The performance of this improved PSD technique was first tested irradiating the SDD by gamma-rays from 60Co and alphas from 241Am radiation sources, respectively. Then, using a 6LiF thermal neutron converter, a successful discrimination between gamma-rays and alpha particles and tritons generated by the 6Li(n,α)3H reaction induced by neutrons from 252Cf spontaneous fission neutron source was achieved. Thanks to this PSD processing technique, the thermal neutron detection efficiency increased about 1.7 times compared to previous measurements performed without the PSD technique. The real-time thermal neutron measurement by SDD with this enhanced PSD processing was also used during D-D plasma discharges in the Large Helical Device (LHD). It was found that both the time integrated counts and the time evolution count rate measured by the SDD reproduced well that of the fission chamber used as official LHD neutron monitor. The capability of the SDD detector using the PSD technique of precise real-time thermal neutron measurement in LHD was demonstrated.

DOI： 10.1016/j.fusengdes.2020.112063

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Scopus

In Vitro Studies to Define the Cell-Surface and Intracellular Targets of Polyarginine-Conjugated Sodium Borocaptate as a Potential Delivery Agent for Boron Neutron Capture Therapy Open Access

Atsushi Fujimura, Seiji Yasui, Kazuyo Igawa, Ai Ueda, Kaori Watanabe, Tadashi Hanafusa, Yasuaki Ichikawa, Sachiko Yoshihashi, Kazuki Tsuchida, Atsunori Kamiya, Shuichi Furuya

CELLS Vol. 9 ( 10 ) 2020.10

Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI

Boron neutron capture therapy (BNCT) requires pharmaceutical innovations and molecular-based evidence of effectiveness to become a standard cancer therapeutic in the future. Recently, in Japan, 4-borono-L-phenylalanine (BPA) was approved as a boron agent for BNCT against head and neck (H&N) cancers. H&N cancer appears to be a suitable target for BPA-BNCT, because the expression levels of L-type amino acid transporter 1 (LAT1), one of the amino acid transporters responsible for BPA uptake, are elevated in most cases of H&N cancer. However, in other types of cancer including malignant brain tumors, LAT1 is not always highly expressed. To expand the possibility of BNCT for these cases, we previously developed poly-arginine peptide (polyR)-conjugated mercaptoundecahydrododecaborate (BSH). PolyR confers the cell membrane permeability and tumor selectivity of BSH. However, the molecular determinants for the properties are not fully understood. In this present study, we have identified the cluster of differentiation 44 (CD44) protein and translational machinery proteins as a major cell surface target and intracellular targets of BSH-polyR, respectively. CD44, also known as a stem cell-associated maker in various types of cancer, is required for the cellular uptake of polyR-conjugated molecules. We showed that BSH-polyR was predominantly delivered to a CD44(High) cell population of cancer cells. Once delivered, BSH-polyR interacted with the translational machinery components, including the initiation factors, termination factors, and poly(A)-biding protein (PABP). As a proof of principle, we performed BSH-polyR-based BNCT against glioma stem-like cells and revealed that BSH-polyR successfully induced BNCT-dependent cell death specifically in CD44(High) cells. Bioinformatics analysis indicated that BSH-polyR would be suitable for certain types of malignant tumors. Our results shed light on the biochemical properties of BSH-polyR, which may further contribute to the therapeutic optimization of BSH-BNCT in the future.

DOI： 10.3390/cells9102149

Observation of neutron emission anisotropy by neutron activation measurement in beam-injected LHD deuterium plasmas Open Access

Sugiyama S, Nishitani T, Matsuura H, Isobe M, Ogawa K, Tanaka T, Yoshihashi S, Uritani A, Osakabe M

NUCLEAR FUSION Vol. 60 ( 7 ) 2020.7

Language：Japanese Publishing type：Research paper (scientific journal)

Neutron emission anisotropy caused by neutral beam injection was observed by the neutron activation measurement in deuterium plasmas confined in the Large Helical Device. The shot-integrated fast neutron flux was measured by the irradiation of activation foils at two irradiation ends located at different ports. The ratio of the flux at the outside horizontal port to that at the lower port was used as an index of neutron emission anisotropy. The dependence of the ratio on the direction of the neutral beam injection was confirmed by comparing cases of tangential, perpendicular and both tangential and perpendicular neutral beam injections. Neutron emission anisotropy was numerically evaluated assuming these three cases of neutral beam injection. The analysis of neutron emission anisotropy comprises the evaluation of the velocity distribution function of energetic deuterons following guiding-centre orbits, calculation of the double-differential emission spectrum of neutrons produced by the D(d,n) 3&rm He reaction and neutron transport calculation. The obtained numerical results are qualitatively consistent in the dependence of neutron emission anisotropy on the neutral-beam-injection direction with the observed experimental data.

DOI： 10.1088/1741-4326/ab90c9

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Scopus

A comparison between simulation and experimental results for depth profile of 6Li reaction rate in a water phantom of BNCT using a small 6Li-based scintillator neutron detector with an optical fiber

Ishikawa, A; Yamazaki, A; Watanabe, K; Yoshihashi, S; Uritani, A; Tsurita, Y; Tsuchida, K; Kiyanagi, Y

RADIATION MEASUREMENTS Vol. 133 2020.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Radiation Measurements

BNCT is a radiation therapy using neutrons. For dosimetry in BNCT, it is important to evaluate the thermal neutron distribution in a water phantom irradiated with neutrons used in the therapy. We proposed application of a small 6Li-based scintillator neutron detector with an optical fiber into a comparison study between simulation and experimental results in BNCT. In this paper, we compared simulation and experimental results for depth profile of 6Li(n,α) reaction rate in a water phantom of BNCT using a developed small 6Li-based scintillator neutron detector. The experimental results well agreed with the simulation ones. However, we found that the self-shielding effect in the detector will be significant even for a small LiF/Eu:CaF2 eutectics scintillator having the mass of 100 μg. We concluded that we have to consider the self-shielding effect in the small 6Li-based scintillator neutron detector when comparing simulation and experimental results of the 6Li(n,α) reaction rate in a water phantom.

DOI： 10.1016/j.radmeas.2020.106270

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Scopus

Output linearity and radiation resistance of an optical fiber-based neutron detector using Li-glass scintillator

Ishikawa Akihisa, Yamazaki Atsushi, Watanabe Kenichi, Yoshihashi Sachiko, Uritani Akira

JSAP Annual Meetings Extended Abstracts Vol. 2020.1 ( 0 ) page： 555 - 555 2020.2

Output linearity and radiation resistance of an optical fiber-based neutron detector using Li-glass scintillator

Ishikawa Akihisa, Yamazaki Atsushi, Watanabe Kenichi, Yoshihashi Sachiko, Uritani Akira

JSAP Annual Meetings Extended Abstracts Vol. 2021.1 ( 0 ) page： 555 - 55 2020.2

Basic study on a LiF-Eu:CaF<inf>2</inf> mixed powder neutron scintillator

Watanabe K

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 954 2020.2

Sensitivity and linearity of optical fiber-based neutron detectors using small6Li-based scintillators

Ishikawa A

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Vol. 954 2020.2

Numerical Study of Turbulent Heat transfer enhancement in square-duct flow through of inline V-shaped discrete ribs

Yu Stu. S., Tsuneyoshi T., Hamaji Y., Yoshihashi S., Ito T., Tsuji Y.

The Proceedings of Conference of Tokai Branch Vol. 2020.69 ( 0 ) page： 520 2020

Design of Neutron Spectrum-Shaping Assembly Around the Pneumatic Tube-End in the LHD Torus Hall for the Medical Research Application Open Access

KOBAYASHI Makoto I., OGAWA Kunihiro, ISOBE Mitsutaka, NISHITANI Takeo, NISHIMURA Teruki, MUKAI Keisuke, YOSHIHASHI Sachiko, OSAKABE Masaki

Plasma and Fusion Research Vol. 15 ( 0 ) page： 2405043 - 2405043 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Plasma Science and Nuclear Fusion Research

The designs of neutron spectrum-shaping assembly (NSSA) composed with various shielding materials with natural isotopic abundance were evaluated to construct the neutron field dominated with thermal neutron or epi-thermal neutron for the application of neutron filed in the torus hall of LHD toward the BNCT research. According to the neutron transport calculation by MCNP6, the fast neutron moderation efficiency was higher in polyethylene (PE) compared to lithium fluoride (LiF) and magnesium fluoride (MF), although LiF showed relatively large epi-thermal and thermal neutron absorption. This comparison showed that the thermal neutron field can be effectively achieved with using PE. For constructing the NSSA which can provide the neutron field dominated with epi-thermal neutron, several NSSA designs were evaluated with respect to fast neutron flux, epi-thermal neutron flux, and gamma-ray dose. The combination of MF, lead (Pb) and cadmium (Cd) can provide the good epi-thermal neutron field with the mitigations of fast neutron flux and gamma-ray dose, which is also suitable for BNCT research in the torus hall of LHD.

DOI： 10.1585/pfr.15.2405043

Development of Optical-fiber-based Neutron Detector Using Li glass Scintillator for an Intense Neutron Field Open Access

Ishikawa, A; Yamazaki, A; Watanabe, K; Yoshihashi, S; Uritani, A; Sakurai, Y; Tanaka, H; Ogawara, R; Suda, M; Hamano, T

SENSORS AND MATERIALS Vol. 32 ( 4 ) page： 1489 - 1495 2020

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Sensors and Materials

The development of a neutron detector for real-time measurements in an intense neutron field is desired. We are developing a quartz optical-fiber-based neutron detector as a real-time neutron monitor. Thus far, Eu:LiCaAlF6 crystals and LiF/Eu:CaF2 eutectics have been used as the scintillators of the quartz optical-fiber-based neutron detectors. These scintillators have high light yields, but relatively long decay time constants, which are the limiting factors for the dynamic range of optical-fiber-based neutron detectors. In this work, we applied a small Li glass scintillator to a quartz optical-fiber-based neutron detector using an optical fiber with high numerical aperture and a UV-curable resin with high transmittance. The fabricated detector showed a clear peak corresponding to neutron events in the pulse height distribution. The radiation resistance was evaluated and no deterioration was observed up to 2 × 1012 n/cm2. The detector output linearity was confirmed up to 450 kcps, which was about ten times larger than that of the detector using the conventional Eu:LiCaAlF6 or LiF/Eu:CaF2 scintillator.

DOI： 10.18494/SAM.2020.2748

Open Access

Web of Science

Scopus

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Papers - YOSHIHASHI Sachiko