Catalog of gamma-ray glows during four winter seasons in Japan

Physical Review Research

Published On 2021/11/15

In 2015, the Gamma-Ray Observation of Winter Thunderstorms (GROWTH) collaboration launched a mapping observation campaign for high-energy atmospheric phenomena related to thunderstorms and lightning discharges. This campaign has developed a detection network of gamma rays with up to 10 radiation monitors installed in the cities of Kanazawa and Komatsu, Ishikawa Prefecture, Japan, where low-charge-center winter thunderstorms frequently occur. During four winter seasons from October 2016 to April 2020, a total of 70 gamma-ray glows, ie, minute-lasting bursts of gamma rays originating from thunderclouds, were detected. Their average duration is 58.9 s. Among the detected events, 77% were observed at night. The gamma-ray glows can be classified into temporally symmetric, temporally asymmetric, and lightning-terminated types based on their count-rate histories. An averaged energy …

Journal

Physical Review Research

Published On

2021/11/15

Volume

3

Issue

4

Page

043117

Authors

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Position

H-Index(all)

44

H-Index(since 2020)

19

I-10 Index(all)

0

I-10 Index(since 2020)

0

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0

Citation(since 2020)

0

Cited By

0

Research Interests

Odor sensor

Dosimeter

Thin films

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Other Articles from authors

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of Alloys and Compounds

Radiophotoluminescence properties of Bi-doped NaCaBO3

Bi-doped NaCaBO3 exhibits radiophotoluminescence (RPL) properties, where the Bi2+ centre is formed through X-ray irradiation. As a result of RPL, a broad emission band appears around 800 nm in the photoluminescence (PL) spectrum, attributed to X-ray irradiation. The intensity of the PL signal is proportional to the irradiation dose, making it useful for measuring accumulated radiation dose. The sensitivity depends on the doping concentration of Bi, and the optimal concentration to maximize sensitivity is approximately 0.005%. With a laboratory-constructed reader system, the optimal sample enables measurement of X-ray dose as low as 25 mGy. Following irradiation, the Bi2+ signal slightly increases by about 13%, but it is significantly reduced to around 7% of the initial value after heat treatment at 500°C for 100 s. The formation and annihilation of the Bi2+ centre can be reproduced multiple times. Therefore …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Sensors and Materials

Radio-photoluminescence Properties of Eu-doped CaBPO5

Eu-doped CaBPO5 was synthesized by the solid-state reaction route, and then its radiophotoluminescence properties were studied. On the basis of steady-state and time-resolved photoluminescence (PL) studies, it was confirmed that Eu2+ is formed by X-ray irradiation due to the valence change of the Eu ion (Eu3+→ Eu2+). In addition, for dosimetric applications, it was demonstrated that the PL intensity of Eu2+ is proportional to the accumulated radiation dose, is stable after irradiation, and can be reversed by heat treatment at 500℃ for 100 s.

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Japanese Journal of Applied Physics

Radiophotoluminescence properties of Eu-doped Li2SrSiO4 for radiation detectors

To search for new radiophotoluminescence (RPL) materials, Eu-doped Li 2 SrSiO 4 was synthesized by the solid-state reaction and then studied its RPL properties for radiation detector applications. All the samples were identified to be Li 2 SrSiO 4 by X-ray diffraction. The as-prepared sample shows photoluminescence (PL) due to Eu 3+ while an additional PL band appears due to a formation of Eu 2+ after X-ray irradiation. This indicates that the Eu-doped Li 2 SrSiO 4 has RPL properties. The sensitivity of RPL (or PL intensity of Eu 2+) to X-ray dose is the highest when the Eu concentration is 0.1%, and the dynamic range is 5–10 000 mGy. In addition, the generated Eu 2+ is so stable that only 5% of the signal degrades over 20 min after irradiation. The RPL signal notably decreases to about 30% of the initial value by heating at 500 C for 100 s, and it is reproducible multiple times even after the heat treatment.

2023/12/20

Article Details
Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of Materials Science: Materials in Electronics

ESR studies to elucidate the origin of the RPL emission of undoped-CaSO4

Recent research has shown that CaSO4, without any intentional addition of impurities, exhibits remarkable radiophotoluminescence (RPL) properties. However, the origin of the RPL in CaSO4 has yet to be fully understood. ESR measurements were carried out to identify the defect species responsible for RPL and elucidate the luminescence’s origin. ESR measurements on undoped-CaSO4 with different radiation sensitivities showed SO4−, SO2−+SO3−, PO42−, Si=O3 in P2O5–SiO2 (E’ center), Al2O3 hole center and Mn2+ defect species in CaSO4. This means that CaSO4 contains Al2O3, Mn2+, P, and Si as impurities, which are not intentionally added to CaSO4. As the results of this study, the different impurity states may influence the radiation sensitivity of the materials. It is suggested that the deliberate addition of P and Si elements, Al2O3 and Mn2+ could control the RPL properties.

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Materials Research Bulletin

X-ray induced reduction of Sm3+ into Sm2+ in Li2CaSiO4 and its potential for radiation measurement applications

In Sm3+-doped Li2CaSiO4, the Sm3+ ion is reduced to the Sm2+ state by X-ray irradiation. The valence change was confirmed by the difference in their photoluminescence spectra, measured before and after irradiation. Only luminescence peaks due to the 4f-4f transitions of Sm3+ are observed before the irradiation while an additional luminescence band is observed at 900 nm due to the 5d-4f transition of Sm2+. The reaction is that a fraction of X-ray generated electrons is captured by Sm3+ ions, which convert to the Sm2+ state. The generated Sm2+ state is fairly stable while it is effectively reversed back to the Sm3+ state by a heat treatment at an elevated temperature. A numerical approximation revealed the activation energy to be 0.40 and 0.52 eV. Even after the heat-treatment, the reduction of Sm3+ to Sm2+ is reproducible multiple times, which shows good potential for using radiation measurement applications.

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of Materials Science: Materials in Electronics

Radio-photoluminescence properties of Eu-doped SrAl2O4 ceramics and thermally assisted charge transfer process

Radio-photoluminescence (RPL) properties of Eu-doped SrAl2O4 are studied focusing on the generation of a luminescent center by ionizing radiation of X-ray and its extinction by a thermally assisted charge transfer. The single phases of SrAl2O4 doped with Eu at concentrations of 0.05–1.0% are synthesized via solid-state reactions, as confirmed by X-ray diffractions analyses. They show photoluminescence (PL) due to both Eu3+ and Eu2+, and the PL intensity due to Eu3+ decreases after X-ray irradiation while the one due to Eu2+ notably increases. This indicates that Eu2+ as a luminescence center is generated as RPL through reduction from Eu3+ to Eu2+ by ionizing radiation of X-ray. Particularly, the 0.1% Eu-doped sample shows the highest sensitivity to X-ray dose, and the lowest detection limit is estimated to be 0.3 Gy with the present reader system. The RPL signal is reasonably stable, and it depends on …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Recent advances in radiophotoluminescence materials for luminescence dosimetry

Radiophotoluminescence (RPL) is a phenomenon in which a luminescence centre is formed in a medium upon interaction with ionizing radiation. The RPL is observed by a conventional photoluminescence (PL) technique, and the PL intensity is proportional to the dose. With the latter feature, the RPL has found successful applications in personnel and environmental dosimetry. However, the conventional materials considered for radiation measurements may be limited to Ag-doped phosphate glass, LiF, and Al 2 O 3: C, Mg. The recent research works, however, have found a number of additional RPL materials for luminescence dosimetry. The aim of the present paper is to review the series of newly reported RPL materials and potential applications in dosimetry.

2022/11/22

Article Details
Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Optically stimulated luminescence dosimeters: principles, phosphors and applications

This review paper discusses the basics of the optically stimulated luminescence (OSL) phenomenon, phosphors for OSL, functional design of OSL phosphors, and application areas of the OSL phenomenon, such as radiation dose monitoring for individual and environmental, computed radiography for medical and dental diagnosis, dating, security, archaeological dating, and autoradiography for drug discovery. Finally, the future prospects of the OSL phenomenon as passive-type dosimeters are mentioned.

2022/11/21

Article Details
Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

IEEJ Transactions on Sensors and Micromachines

Proposal of Temperature Behavior Analysis and Temperature Dependence Reduction of Stem Water Content Variation Sensor

Proposal of Temperature Behavior Analysis and Temperature Dependence Reduction of Stem Water Content Variation Sensor - NASA/ADS Now on home page ads icon ads Enable full ADS view NASA/ADS Proposal of Temperature Behavior Analysis and Temperature Dependence Reduction of Stem Water Content Variation Sensor Ueno, Chiemi ; Hirasawa, Kazuki ; Takei, Yoshinori ; Nanto, Hidehito Abstract Publication: IEEJ Transactions on Sensors and Micromachines Pub Date: June 2022 DOI: 10.1541/ieejsmas.142.117 Bibcode: 2022IJTSM.142..117U No Sources Found © The SAO/NASA Astrophysics Data System adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A NASA logo Smithsonian logo Resources About ADS ADS Help What's New Careers@ADS Social @adsabs ADS Blog Project Switch to full ADS Is …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Sensors and Materials

Radiophotoluminescence Imaging Reader for Passive Dosimetry

In this study, we constructed an image reader system for two-dimensional radiation dosimetry based on radiophotoluminescence (RPL). The reader system mainly consists of a Peltier-cooled CMOS camera and an LED excitation source, as well as control units, and it offers an arbitrary excitation wavelength (eg, 365, 405, 460, 530, and 630 nm) and a wide spectral detection range (200–1000 nm) to be used for a wide range of prototype image detectors having different spectral features. Using the developed system, we were able to successfully obtain X-ray projection images recorded on a commercial RPL detector [Ag-doped phosphate glass (Ag-PG) plate] as well as custom-made prototypes of flexible imaging plates (IPs). Furthermore, the reader system is applicable not only for RPL imaging but also for conventional optically stimulated luminescence (OSL) imaging, which was demonstrated by using a …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Japanese Journal of Applied Physics

RPL properties of samarium-doped CaSO4

Radiophotoluminescence (RPL) properties of Sm-doped CaSO 4 for radiation dosimetry applications are reported. The samples with varying Sm concentrations are prepared via the solid-state reaction process. The as-prepared samples show photoluminescence due to typical 4f–f transitions of Sm 3+ whereas, after X-ray irradiation, additional emission features appear with a broad band peaking at 630 nm as well as a set of multiple sharp lines across 680–820 nm, which are attributed to the 5d–4f and 4f–4f transitions of Sm 2+, respectively. Therefore, the RPL in the present material system relies on the generation of Sm 2+ centers. The sensitivity is about 3 times lower than that of Ag-doped phosphate glass, but no fading and build-up of signal are evident even immediately after the irradiation. The signal is reversible by heat-treatment at 500 C, and is reproducible even after the thermal erasure, especially when …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Phosphors for Radiation Detectors

radiophotoluminescence (RPL)

This chapter covers a wide range of radio‐photoluminescence (RPL) technologies, from fundamentals to applications. It presents the definition of the term of RPL and distinguishes it from thermally‐stimulated luminescence and optically‐stimulated luminescence as a different type of dosimetric technique using a phosphor medium. RPL is a very powerful tool when the measurement environment requires exposure to light or heat. The chapter introduces a list of RPL materials and their fundamental properties, as reported in the literature. The RPL center is typically very stable and the resulting luminescence is due to electronic transitions within the RPL center. The chapter also introduces the principal properties as well as applications of four selected RPL materials with many illustrative materials. These include: Ag‐doped sodium‐aluminophosphate glasses, Al …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Phosphors for Radiation Detectors

Optically‐Stimulated Luminescent Dosimeters

The luminescence phenomenon due to the thermal stimulation is called thermally‐stimulated luminescence (TSL), while the one due to the optical stimulation is called optically‐stimulated luminescence (OSL). This chapter focuses on the principles and applications of OSL, which are utilized today in personnel dose monitoring, environmental dose monitoring, and geographical dating. OSL phenomenon has been used in personnel dose monitoring and imaging plates for computed radiography since the 1980s. A dosimeter using C‐doped Al 2 O 3 (Al 2 O 3 :C) developed by Landauer, Inc. is one of those passive‐type dosimeters using OSL phenomenon for personnel dose monitoring applications. Al 2 O 3 :C …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Journal of The Institute of Electrical Engineers of Japan

What Did the Great Persons Who Changed the World Think and Say?

What Did the Great Persons Who Changed the World Think and Say? - NASA/ADS Now on home page ads icon ads Enable full ADS view NASA/ADS What Did the Great Persons Who Changed the World Think and Say? Nanto, Hidehito Abstract Publication: Journal of The Institute of Electrical Engineers of Japan Pub Date: January 2022 DOI: 10.1541/ieejjournal.142.34 Bibcode: 2022JIEEJ.142...34N full text sources Publisher | © The SAO/NASA Astrophysics Data System adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A NASA logo Smithsonian logo Resources About ADS ADS Help What's New Careers@ADS Social @adsabs ADS Blog Project Switch to full ADS Is ADS down? (or is it just me...) Smithsonian Institution Smithsonian Privacy Notice Smithsonian Terms of Use Smithsonian Astrophysical Observatory …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Materials Letters

Radiation-induced reduction of Eu3+ doped in SrAl2O4

In this letter, we report radio-photoluminescence (RPL) properties of Eu-doped SrAl2O4. The RPL is a phenomenon in which a new luminescence center is generated by ionizing radiation. The material was synthesized via the solid-state reaction. The synthesized sample shows photoluminescence (PL) due to the 4f-4f transition of Eu3+ and the 4f65d1 → 4f7 transition of Eu2+. After X-ray irradiation, the former emission intensity decreases while the latter one increases, and the extent of the change depends on the radiation dose. The change in the RPL is attributed to a reduction of Eu3+ by trapping an X-ray generated electron (Eu3+→Eu2+). In addition, a heat-treatment effectively reverses the above reaction by detrapping an electron from the Eu2+ center.

2021/11/15

Article Details
Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Sensors & Materials

TSL/OSL/RPL Automated and Integrated Measurement System (TORAIMS).

Thermally stimulated luminescence (TSL), optically stimulated luminescence (OSL), and radio-photoluminescence (RPL) are radiation-induced luminescence phenomena, and they are widely used for radiation dosimetry today. Despite their successful applications, the R&D of conventional and new phosphor materials is still actively performed in a wide range of research fields from basic science to application. Although these phenomena are considered to be different, they share common physical processes such as the generation, trapping, and transfer of electronic charges. In order to have a deeper look into these phenomena, it is important to comprehensively characterize those of a single material. For this, we have constructed a prototype TSL/OSL/RPL automated and integrated measurement system (TORAIMS), and then the system performance has been studied. The system offers automated and integrated …

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Radioprotection

Characterization of optically-stimulated luminescence properties by NaCl: Eu2+ crystal and the thermal response

[en] Landauer optically stimulated luminescence (OSL) technology nanoDot dosimeters (OSLDs) are characterized for use in mammography screening at various tube voltages, mAs values and target/filter combinations. The average glandular dose (AGD) for a 50-mm breast, based on the representative compressed breast thickness of a 45-mm polymethyl methacrylate (PMMA) phantom, is assessed using OSLDs with different beam conditions. Further, the linearity of the OSLD response is measured and angular dependence tests are performed for various tube potentials, mAs and target/filter combinations. The breast-absorbed doses are measured at various depths for a 32-kVp X-ray beam at 100 mAs, with a Mo/Rh target/filter combination. The measured incident air kerma values at different lateral positions exhibit a maximum deviation of 6%, and the average relative response of the OSLDs at the reference point (center) with respect to various lateral positions is found to be 1.001±0.09%. The calculated AGD values are in the 1.3±0.1-3.5±0.2 mGy range, depending on the tube potential, tube loading and target/filter combinations. An exposure setup featuring the auto-exposure control (AEC) mode, 28 kVp, 73.8 mAs, and a Mo/Rh target/filter combination may be preferred for mammography screening for a compressed breast thickness of 45 mm.(authors)

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

電気学会研究会資料

Transient response analysis and feature extraction of semiconductor gas sensors for an application to machine olfaction

瀬戸就一 他: 半導体式ガスセンサの過渡応答出力の解析, 電気学会論文誌 E センサマイクロマシン準部門誌 Vol. 125 No. 3, p. 129-134 (2005)

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

Radiation Measurements

Physical and dosimetric characteristics of radiophotoluminescent glass from two-photon excitation microscopy

We investigate the physical and dosimetric characteristics of Ag-activated phosphate glass exposed to proton beams with various energies. We present time-resolved blue and orange radiophotoluminescent (RPL) spectra and examine the dependence of the peak wavelengths and RPL area intensities on gate time. Moreover, we consider various micro-scale 3D patterns written on Ag-activated glass by a focused proton beam and evaluate their orange and blue RPL axial-profiles using two-photon excitation microscopy. Finally, we discuss the remarkable broadening of the Bragg curve observed in Ag-activated glass and argue that it should be attributed to the saturation effect and/or non-linearity effect from the viewpoint of the relation between the dose delivered and the signal.

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Physical Review Research

Stick-slip in a stack: How slip dissonance reveals aging

We perform physical and numerical experiments to study the stick-slip response of a stack of slabs in contact through dry frictional interfaces driven in quasistatic shear. The ratio between the drive's stiffness and the slab's shear stiffness controls the presence or absence of slip synchronization. A sufficiently high stiffness ratio leads to synchronization, comprising periodic slip events in which all interfaces slip simultaneously. A lower stiffness ratio leads to asynchronous slips and, experimentally, to the stick-slip amplitude becoming broadly distributed as the number of layers in the stack increases. We interpret this broadening in light of the combined effect of complex loading paths, due to the asynchronous slips, and interface aging. Consequently, the aging rate of the interfaces can be readily extracted from the stick-slip cycles, and it is found to be of the same order of magnitude as existing experimental results on a …

Luca Giomi

Luca Giomi

Universiteit Leiden

Physical Review Research

Defect-populated configurations in nematic solid tori and cylinders

We make toroidal droplets of nematic liquid crystal and explore the defect-populated stable configurations that appear after heating to the isotropic phase and cooling back to the nematic phase. These configurations, as confirmed by simulations, are made of defect pairs where the positive/negative defect is located in the region of maximum positive/negative Gaussian curvature. Moreover, we demonstrate through experiments and simulations that these defect pairs also appear and are stable in cylinders, which have zero Gaussian curvature, highlighting the crucial role of bulk nematic elasticity in stabilizing these structures.

TS Monteiro

TS Monteiro

University College London

Physical Review Research

Sensing directional noise baths in levitated optomechanics

Optomechanical devices are being harnessed as sensors of ultraweak forces for applications ranging from inertial sensing to the search for the elusive dark matter. For the latter, there is a focus on detection of either higher energy single recoils or ultralight, narrow-band sources; a directional signal is expected. However, the possibility of searching for a stochastic stream of weak impulses, or more generally a directional broadband signal, need not be excluded; with this and other applications in mind, we apply Gaussian white noise impulses with a well defined direction Ψ to a levitated nanosphere trapped and 3D cooled in an optical tweezer. We find that cross-correlation power spectra offer a calibration-free distinctive signature of the presence of a directional broadband force and its orientation quadrant, unlike normal power spectral densities (PSDs). We obtain excellent agreement between theoretical and …

P. Elli Stamatopoulou

P. Elli Stamatopoulou

Syddansk Universitet

Physical Review Research

Electron beams traversing spherical nanoparticles: analytic and numerical treatment

We present an analytic, Mie theory-based solution for the energy loss and the photon-emission probabilities in the interaction of spherical nanoparticles with electrons passing nearby and through them, in both cathodoluminescence and electron energy-loss spectroscopies. In particular, we focus on the case of penetrating electron trajectories, for which the complete fully electrodynamic and relativistic formalism has not been reported as yet. We exhibit the efficiency of this method in describing collective excitations in matter through calculations for a dispersive and lossy system, namely a sphere described by a Drude permittivity. Subsequently, we use the analytic solution to corroborate the implementation of electron-beam sources in a state-of-the-art numerical method for problems in electrodynamics, the discontinuous Galerkin time-domain (DGTD) method. We show that the two approaches produce spectra in …

Benedikt Tissot

Benedikt Tissot

Universität Konstanz

Physical Review Research

Reservoir engineering for classical nonlinear fields

Reservoir engineering has become a prominent tool to control quantum systems. Recently, there have been first experiments applying it to many-body systems, especially with a view to engineer particle-conserving dissipation for quantum simulations using bosons. In this paper, we explore the dissipative dynamics of these systems in the classical limit. We derive a general equation of motion capturing the effective nonlinear dissipation introduced by the bath and apply it to the special case of a Bose-Hubbard model, where it leads to an unconventional type of dissipative nonlinear Schrödinger equation. Building on that, we study the dynamics of one and two solitons in such a dissipative classical field theory.