研究者業績
基本情報
- 所属
- 千葉大学 大学院理学研究院 物理学研究部門 特任研究員
- 学位
- 博士（理学）(千葉大学)
- 研究者番号
- 10573280
- J-GLOBAL ID
- 201801018344874900
- researchmap会員ID
- B000299091
主要な経歴
7-
2024年6月 - 現在
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2014年7月 - 2024年5月
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2009年5月 - 2014年6月
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2009年4月 - 2009年4月
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2007年4月 - 2009年3月
学歴
3-
2006年4月 - 2009年3月
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2004年4月 - 2006年3月
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2000年4月 - 2004年3月
委員歴
1-
2013年11月 - 2013年11月
主要な論文
107-
Journal of Physics: Conference Series 2374(1) 012114-012114 2022年12月6日 査読有り筆頭著者責任著者Around 1980, Japan’s High Energy Accelerator Research Organization, also known as the KEK laboratory, began developing silica aerogels as a Cherenkov radiator. In 1996, the high energy physics group at Chiba University, Japan, began aerogel research and development in collaborating with KEK. The design of state-of-the-art Cherenkov detectors is enabled by improving aerogel transparency. Simultaneously, ultrahigh- and ultralow-refractive-index aerogels were developed to bridge the gap in the available indices for identifying low- and high-momentum particles, respectively. These are and will be employed in ongoing and future particle physics experiments all over the world. We report the latest results from the aerogel development and applications to threshold-type and ring-imaging Cherenkov detectors.
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Physics Letters B 826 136913-136913 2022年3月 査読有り
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Astrobiology 21(12) 1451-1460 2021年8月27日 査読有りThe Tanpopo experiment was the first Japanese astrobiology mission on board the Japanese Experiment Module Exposed Facility on the International Space Station (ISS). The experiments were designed to address two important astrobiological topics, panspermia and the chemical evolution process toward the generation of life. These experiments also tested low-density aerogel and monitored the microdebris environment around low Earth orbit. The following six subthemes were identified to address these goals: (1) Capture of microbes in space: Estimation of the upper limit of microbe density in low Earth orbit; (2) Exposure of microbes in space: Estimation of the survival time course of microbes in the space environment; (3) Capture of cosmic dust on the ISS and analysis of organics: Detection of the possible presence of organic compounds in cosmic dust; (4) Alteration of organic compounds in space environments: Evaluation of decomposition time courses of organic compounds in space; (5) Space verification of the Tanpopo hyper-low-density aerogel: Durability and particle-capturing capability of aerogel; (6) Monitoring of the number of space debris: Time-dependent change in space debris environment. Subthemes 1 and 2 address the panspermia hypothesis, whereas 3 and 4 address the chemical evolution. The last two subthemes contribute to space technology development. Some of the results have been published previously or are included in this issue. This article summarizes the current status of the Tanpopo experiments.
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Astrobiology 21(12) 1461-1472 2021年8月27日 査読有り
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Nuclear Instruments and Methods in Physics Research A 952 161879 2020年2月 査読有り筆頭著者責任著者
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JOURNAL OF SUPERCRITICAL FLUIDS 110 183-192 2016年4月 査読有り筆頭著者責任著者This study presents the development of large-area (18 cm x 18 cm x 2 cm), high refractive index (n similar to 1.05) hydrophobic silica aerogel tiles for use as Cherenkov radiators. These transparent aerogel tiles will be installed in a Cherenkov detector for the next-generation accelerator-based particle physics experiment Belle II, to be performed at the High Energy Accelerator Research Organization (KEK) in Japan. Cracking has been eliminated from the prototype aerogel tiles by improving the supercritical carbon dioxide (scCO(2)) extraction procedure when drying the wet gel tiles. Finally, a method of mass-producing aerogel tiles for the actual detector was established. It was confirmed that the experimentally manufactured aerogel tiles meet the required optical and hydrophobic characteristics and have a uniform tile density. (C) 2015 Elsevier B.V. All rights reserved.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 77(2) 325-334 2016年2月 査読有り筆頭著者責任著者The fabrication of an ultralow-density hydrophobic silica aerogel for the intact capture cosmic dust during the Tanpopo mission is described. The Tanpopo experiment performed on the International Space Station orbiting the Earth includes the collection of terrestrial and interplanetary dust samples on a silica aerogel capture medium exposed to space for later ground-based biological and chemical analyses. The key to the mission's success is the development of high-performance capture media, and the major challenge is to satisfy the mechanical requirements as a spacecraft payload while maximizing the performance for intact capture. To this end, an ultralow-density (0.01 g cm(-3)) soft aerogel was employed in combination with a relatively robust 0.03 g cm(-3) aerogel. A procedure was also established for the mass production of double-layer aerogel tiles formed with a 0.01 g cm(-3) surface layer and a 0.03 g cm(-3) open-topped, box-shaped base layer, and 60 aerogel tiles were manufactured. The fabricated aerogel tiles have been demonstrated to be suitable as flight hardware with respect to both scientific and safety requirements. [GRAPHICS] .
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 766 212-216 2014年12月 査読有り筆頭著者責任著者This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4a at momenta up to 4 GeV/c. Large-area aerogel Liles (over 18 x 18 x 2 cm(3)) were first fabricated in Lest productions by pin drying in addition to conventional methods. We proposed to fill the large end-cap region (area 3.5 m2) with 124 water-jet-trimmed fan-shaped dual-layer-focusing aerogel combinations of different refractive indices (1.045 and 1.055). Guided by the test production results, we decided to manufacture aerogels by the conventional method and are currently proceeding with mass production. In an electron beam Lest undertaken at the DESY, we confirmed that the Klif separation capability of a prototype A-RICH counter exceeded 4c at 4 GeWc. (C) 2014 Elsevier By. All rights reserved.
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Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan 12(ists29) Pk_29-Pk_34 2014年8月 査読有り筆頭著者責任著者
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 697 52-58 2013年1月 査読有り筆頭著者責任著者This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n = 1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is vertical bar delta(n-1)/(n-1)vertical bar < 4% in a focusing dual layer radiator (with different refractive indices) scheme. We applied the radiographic technique to evaluate the density uniformity of our original aerogels from a trial production and that of Panasonic products (SP-50) as a reference, and to confirm they have sufficient density uniformity within +/- 1% along the transverse plane direction. The measurement results show that the proposed technique can quantitatively estimate the density uniformity of aerogels. (c) 2012 Elsevier B.V. All rights reserved.
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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 59(5) 2506-2511 2012年10月 査読有り筆頭著者責任著者We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring-imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 668 64-70 2012年3月 査読有り筆頭著者責任著者We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n=1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels. (C) 2011 Elsevier B.V. All rights reserved.
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PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON TECHNOLOGY AND INSTRUMENTATION IN PARTICLE PHYSICS (TIPP 2011) 37 642-649 2012年 査読有り筆頭著者責任著者In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test. (C) 2012 Published by Elsevier B. V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.
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Biological Sciences in Space 25(1) 7-12 2011年4月 査読有り筆頭著者責任著者Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on the International Space Station. Glass particles as a simulated cosmic dust with 30 _m in diameter and 2.4 g/cm3 in density were successfully captured by the novel aerogel at a velocity of 6 km/s. Background levels of contaminated DNA in the ultra-low density aerogel were lower than the detection limit of a polymerase chain reaction assay. These results show that the manufactured aerogel has good performance as a cosmic dust collector and sufficient quality in respect of DNA contamination. The aerogel is feasible for the biological analyses of captured cosmic dust particles in the astrobiological studies.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 623(1) 339-341 2010年11月 査読有り筆頭著者責任著者We have succeeded in developing hydrophobic silica aerogels over a wide range of densities (i.e. refractive indices). A pinhole drying method was invented to make possible producing highly transparent aerogels with entirely new region of refractive indices of 1.06-1.26. Obtained aerogels are more transparent than conventional ones, and the refractive index is well controlled in the pinhole drying process. A test beam experiment was carried out in order to evaluate the performance of the pinhole-dried aerogels as a Cherenkov radiator. A clear Cherenkov ring was successfully observed by a ring imaging Cherenkov counter. We also developed monolithic and hydrophobic aerogels with a density of 0.01 g/cm(3) (a low refractive index of 1.0026) as a space dust capturer for the first time. Consequently, aerogels with any refractive indices between 1.0026 and 1.26 can be produced freely. (C) 2010 Elsevier B.V. All rights reserved.
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2005 IEEE Nuclear Science Symposium Conference Record, Vols 1-5 816-818 2005年10月 査読有り筆頭著者責任著者New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm at 400 nm wave length. A mold made of alcogel which endures shrinkage in the supercritical drying process has provided aerogel with the extremely low density of 0.009g/cm(3), which corresponds to the refractive index of 1.002. We have succeeded producing aerogel with a wide range of densities.
MISC
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宇宙環境利用シンポジウム 第34回： 令和元年度 = Space Utilization Research, Vol. 34 2019: Proceedings of The Thirty-fourth Space Utilization Symposium (34) 2020年1月第34回宇宙環境利用シンポジウム (2020年1月21日-22日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 12名資料番号: SA6000145009
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平成29年度宇宙科学に関する室内実験シンポジウム 講演集 = Proceedings of 2018 Symposium on Laboratory Experiment for Space Science 2018年2月平成29年度宇宙科学に関する室内実験シンポジウム (2018年2月26日-27日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県資料番号: SA6000123037
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日本地球惑星科学連合大会予稿集(Web) 2018 ROMBUNNO.BAO01‐03 (WEB ONLY) 2018年
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宇宙環境利用シンポジウム 第32回： 平成29年度 = Space Utilization Research, Vol. 32 2017: Proceedings of The Thirty-second Space Utilization Symposium 62nd(32) ROMBUNNO.1H20 2018年1月第32回宇宙環境利用シンポジウム (2018年1月15日-16日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 12名資料番号: SA6000117017
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 104-107 2017年12月For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward end-cap region of the spectrometer. The detector will provide about 4 sigma separation of pions and kaons up to momenta of 3.5 GeV/c, at the kinematic limits of the experiment. We present the up-to-date status of the ARICH simulation and reconstruction software, focusing on the recent improvements of the reconstruction algorithms and detector description in the Geant4 simulation. In addition, as a demonstration of detector readout software functionality we show the first cosmic ray Cherenkov rings observed in the ARICH.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 149-152 2017年12月The Aerogel Ring-Imaging Cherenkov detector (ARICH) is being installed in the endcap region of Belle II spectrometer to identify particles from B meson decays by detecting the Cherenkov ring image from aerogel radiators. To detect single photons, high-sensitive photon detector which has wide effective area (similar to 70 mm x 70 mm), a Hybrid Avalanche Photo Detector (HAPD), has been developed in a collaboration with Hamamatsu K.K. The HAPD consists of hybrid structure of a vacuum tube and an avalanche photodiode (APD). It can be operated in 1.5 T magnetic field of the spectrometer and withstands the radiation levels expected in the Belle II experiment. There are two steps of electric pulse amplification: acceleration of photo-electron in electric field in the vacuum tube part and electron avalanche in the APD part resulting in total gain of order 10(5). For the ARICH, we use 420 HAPDs in total. Before installing them, we performed quality assessment studies such as measurements of dark current, noise level, signal-to-noise ratio and two-dimensional scan with laser illumination. We also measured quantum efficiency of the photocathode. During the HAPD performance tests in the magnetic field, we observed very large signal pulses which cause long dead time of the readout electronics in some of the HAPDs. We have carried out a number of studies to understand this phenomenon, and have found a way to mitigate it and suppress the degradation of the ARICH performance. In this report, we will show a summary of the HAPD performance and quality assessment measurements including validation in the magnetic field for all of the HAPDs manufactured for the ARICH in the Belle II.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 269-271 2017年12月The proximity-focusing Aerogel Ring-Imaging Cherenkov detector (ARICH) has been designed to separate kaons from pions in the forward end-cap of the Belle II spectrometer. The detector will be placed in 1.5 T magnetic field and must have immunity to it. In ARICH R&D, we solve the problem with new equipment called Hybrid Avalanche Photo-Detector (HAPD) which developed by Hamamatsu Photonics. Recently the production of about 500 HAPDs was completed. We test HAPDs in magnetic field in KEK. We found some HAPDs have significant amount of dead time, which reaches up to 30% in the worst case. The dead time is caused by very large (more than 10,000 times larger than a single photon signal) and frequent (similar to 5 Hz) signals, which make electronics paralysed. The huge signals are observed in about 30% of HAPDs. To identify the origin and understand the mechanism, we perform some extra test of HAPDs. We find a strange dependence of the huge signals to the APD bias voltage. If we reduce the bias voltage applied to one of the 4 APDs by 10 V, the frequency of the huge signals is much reduced. On the other hand, if we reduce the voltage of all the 4 HAPDs, huge signals do not decrease, or even increase in some case. We also find the huge signals seems to be related to the vacuum inside HAPD. We present about the observation of the huge signals of HAPDs in the magnetic field, and our strategy to manage it. (C) 2017 Elsevier B.V. All rights reserved.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 176-180 2017年12月The Belle II detector is under construction at KEK in Japan. In the forward endcap region of the Belle II detector, particle identification (PID) is performed by the Aerogel Ring Imaging Cherenkov (ARICH) counter composed of aerogel tiles and 144-channel Hybrid Avalanche Photo-Detectors (HAPDs). The photon detection efficiency of the photosensor is important for a stable operation of the ARICH. To examine the performance of the HAPDs periodically, a monitor system using scattered photons injected by optical fibers is being developed. In this paper, we report the test using the prototype monitor system and the tests with a partially built ARICH detector.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 129-132 2017年12月We have developed a RICH counter as a new forward particle identification device for the Belle II experiment. As a Cherenkov radiator in this counter, a dual aerogel layer combination consisting of two refractive indicies, n=1.045 and 1.055, is employed. Mass production of these aerogel tiles has been done during 2013-2014 with new method improved by Chiba group. Optical qualities for them have been examined. The refractive indices of the obtained tiles were found to be in good agreement with our expectations, and the transparencies were high enough to be used for the RICH radiator.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 241-245 2017年12月A slow control system (SCS) for the Aerogel Ring Imaging Cherenkov (ARICH) counter in the Belle II experiment was newly developed and coded in the development frameworks of the Belle II DAQ software. The ARICH is based on 420 Hybrid Avalanche Photo-Detectors (HAPDs). Each HAPD has 144 pixels to be readout and requires 6 power supply (PS) channels, therefore a total number of 2520 PS channels and 60,480 pixels have to be configured and controlled. Graphical User Interfaces (GUIs) with detector oriented view and device oriented view, were also implemented to ease the detector operation. The ARICH SCS is in operation for detector construction and cosmic rays tests. The paper describes the detailed features of the SCS and preliminary results of operation of a reduced set of hardware which confirm the scalability to the full detector.
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 876 265-268 2017年12月In the forward end-cap of the Belle II spectrometer, a proximity focusing Ring Imaging Cherenkov counter with an aerogel radiator will be installed. The detector will occupy a limited space inside solenoid magnet with longitudinal field of 1.5 T. It will consist of a double layer aerogel radiator, an expansion volume and a photon detector. 420 Hamamatsu hybrid avalanche photo sensors with 144 channels each will be used to read out single Cherenkov photons with high efficiency. More than 60,000 analog signals will be digitized and processed in the front end electronics and send to the unified experiment data acquisition system. The detector components have been successfully produced and are now being installed in the spectrometer. Tested before on the bench, they are currently being installed in the mechanical frame. Part of the detector have been commissioned and connected to the acquisition system to register the cosmic ray particles. The first preliminary results are in accordance with previous expectations. We expect an excellent performance of the device which will allow at least a 4s separation of pions from kaons in the experiment kinematic region from 0.5 GeV/c to 4 GeV/c. (C) 2017 Elsevier B.V. All rights reserved.
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2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop, NSS/MIC/RTSD 2016 2017- 2017年10月16日A new detector, real-time 90Sr counter, was developed with sensitivity to 90Sr and less sensitivity to 137Cs, 40K and Cosmic rays, based on Cherenkov radiation. The detector is a threshold type Cherenkov counter using silica aerogel with a refractive inde× less than 1.042. Since of the threshold energy of 1.31 MeV, the beta ray from 90y can be identified. This detector would be applied for recovery Fukushima. By the Fukushima Nuclear Accident in 2011, particularly the fisheries were severely damaged due to radioactive contamination in Fukushima, Japan. Recent study is focused to radiation with longer half-life, 90Sr and 137Cs, in the contaminated water. In the study, the veto counter suppressed background event from cosmic rays was upgraded to performance with the detection efficiency of 99.9% or more. As the results, an absolute efficiency of 90Sr, 137Cs, and 40K as the performance of detector was evaluated to 2.01 × 10-3 , 1.87 × 10-6 , and 1.75 × 10-5 Bq-1 S-l using the sources, respectively. The efficiency uniformity depending on the source position was measured as peak at the center of the detector and half of the ma×imum value at the edge, the mean efficiency is estimated as (1.68 0.24) × 10-3 Bq-1S -1. The relation between the radioactivity and count rate was observed as response linearity, which is fitted a good linear function. Therefore, the count rate was corresponded to radioactivity concentration of contamination in a sample. Detection limit was estimated to be 1.93 (seawater) and 57.3 Bq kg-1 (seafood).
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平成28年度宇宙科学に関する室内実験シンポジウム 講演集 = Proceedings of 2017 Symposium on Laboratory Experiment for Space Science 2017年2月平成28年度宇宙科学に関する室内実験シンポジウム (2017年2月27日-28日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県資料番号: SA6000095036
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 845 459-462 2017年2月For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward endcap region of the spectrometer. The main challenge was the development of a reliable multichannel sensor for single photons that Operates in the high magnetic field of the spectrometer (1.5 T) and withstands the radiation levels expected at the experiment. A 144 channel Hybrid Avalanche Photo-Detector (HAPD) was developed with Hamamatsu Photonics K.K. and the mass production of similar to 480 HAPDs was completed recently. While our first tests of HAPD performance in the magnetic field (before mass production) showed no issues, we lately observed a presence of very large signal pulses (similar to 5000 x single photon signal), generated internally within about 20% of HAPDs, while operating in the magnetic field. The rate of these pulses varies from sample to sample. These pulses impact the HAPD performance in two ways: they introduce periods Of dead time and, in some cases, damage to the front-end electronics was observed. Here we present conditions under which such large pulses are generated, their properties and impact on HAPD performance, and discuss possible mechanism of their origin. (C) 2016 Elsevier B.V. All rights reserved.
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日本地球惑星科学連合大会予稿集(Web) 2017 ROMBUNNO.BAO01‐04 (WEB ONLY) 2017年
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日本物理学会講演概要集 72 95-95 2017年<p>π/K識別を目的として、Belle II測定器のエンドキャップに実装されるRICH検出器のシリカエアロゲル輻射体を開発した。高い透明度をもち、大面積（18 cm × 18 cm × 2 cm）で高屈折率（1.045と1.055）のエアロゲルの量産に成功した。疎水性エアロゲルをウォータージェットカッターで扇形に成形し、円筒形構造体の124のセルに2つの屈折率を組み合わせて組み込んだ。本講演では、エアロゲルの光学測定と組み込みの結果を報告する。</p>
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日本物理学会講演概要集 72 98-98 2017年<p>Belle II実験のARICHでは真空管とシリコン検出器のハイブリッド構造を持つ光検出器HAPDが磁場中で使用される。試作品を用いた先行研究では、磁場中においてバックグラウンドが抑制されることが測定されていた。しかし、一部の量産品において、磁場の影響で真空管内の光電子軌道が変化してパルスが生じることが新たに判明した。本講演では、量産されたHAPDの磁場によるパルスの影響と対策について報告する。</p>
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平成27年度宇宙科学に関する室内実験シンポジウム 講演集 = Proceedings of 2016 Symposium on Laboratory Experiment for Space Science 2016年2月平成27年度宇宙科学に関する室内実験シンポジウム (2016年2月23日-24日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県著者人数: 12名資料番号: SA6000055004
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宇宙環境利用シンポジウム 第30回： 平成27年度 = Space Utilization Research, Vol. 30 2015: Proceedings of The Thirtieth Space Utilization Symposium 2016(30) ROMBUNNO.BAO01‐05 (WEB ONLY) 2016年1月第30回宇宙環境利用シンポジウム (2016年1月19日-20日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 12名資料番号: SA6000048037
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日本地球惑星科学連合大会予稿集(Web) 2016 ROMBUNNO.BAO01‐07 (WEB ONLY) 2016年
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日本物理学会講演概要集 71 67-67 2016年<p>我々は3種類の低コストで位置分解能の高い大面積荷電粒子検出器を開発した。1つは我々が開発したPET用γ線検出器を利用したものであり、大きさは50 cm x 50 cm、位置分解能は標準偏差で0.1 mm、コストは100万円である。他2つは大きさ2 m x 2 m、位置分解能0.12 mm、コスト1000万円の検出器および、大きさ10 m x 10 m、位置分解能1 mm、コスト5000万円の検出器であり、n進数で信号を読み取ることで使用する受光素子の数を大幅に節約している。</p>
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日本物理学会講演概要集 71 191-191 2016年<p>我々はJ-PARCで計画されている!LaTeX${\Sigma}$p散乱実験において粒子識別に用いるエアロゲルチェレンコフ検出器を開発している。この実験では大強度!LaTeX$\pi$ビームを使用するため本検出器には高いレート耐性が要求される。はじめにモンテカルロシミュレーションを用いてデザインの最適化を行った。そのデザインをもとに試作機を作製し、今年の6月、東北大電子光理学研究センターにおいて性能評価実験を行った。本講演では現在までの開発状況を報告する。</p>
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METEORITICS & PLANETARY SCIENCE 50 2015年8月
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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 787 59-63 2015年7月The Belle II detector, a follow up of the very successful Belle experiment, is under construction at the SuperKEKB electron-positron collider at KEK in Japan. For the PID system in the forward region of the spectrometer, a proximity-focusing ring-imaging Cherenkov counter with an aerogel radiator is being developed. For the position sensitive photon sensor, a 144-channel Hybrid Avalanche Photo-Detector has been developed with Hamamatsu Photonics K.K. In this report, we describe the specification of the Hybrid Avalanche Photo-Detector and the status of the mass production. (C) 2014 Elsevier BM. All rights reserved.
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宇宙航空研究開発機構特別資料: 第6回スペースデブリワークショップ講演資料集 = JAXA Special Publication: Proceedings of the 6th Space Debris Workshop (14) 550-551 2015年3月27日第6回スペースデブリワークショップ (2014年12月17-19日. 宇宙航空研究開発機構調布航空宇宙センター(JAXA)(CAC)), 調布市, 東京本研究は，ISS搭載予定の「たんぽぽ」プロジェクトの一環である．きぼう曝露部に設置される捕集パネルへの衝突粒子数と，微小デブリ環境モデルとの整合性を確認することが最終目的である．たんぽぽ捕集パネルに衝突する粒子衝突頻度解析を，デブリ衝突リスク解析ツール「Turandot」を用いて行った．ISSの立体モデルをツール内に作成し，MASTER-2009コードを環境モデルとして適用させた．2015年初頭から1年間の軌道上曝露を考えた結果を下図に示した．縦軸に1年間あたり，1m2あたりの累積衝突頻度を，横軸に衝突粒子の直径を示している．ここで，RAMはISSの進行方向面，JEM-INは与圧部側の面，JEM-OUTはその反対面，SPACEは宇宙に面しており，WAKEはRAMと反対の面である．RAM面に設置した捕集パネルには，直径0.01mm以上の宇宙塵ないし微小デブリが14個以上衝突すると予想された．また，ISASの2段式軽ガス銃を用いて行った，捕集パネル材のキャリブレーション試験についても報告する．形態: カラー図版あり資料番号: AA1530025048
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宇宙航空研究開発機構特別資料: 第6回スペースデブリワークショップ講演資料集 = JAXA Special Publication: Proceedings of the 6th Space Debris Workshop (14) 548-549 2015年3月27日第6回スペースデブリワークショップ (2014年12月17-19日. 宇宙航空研究開発機構調布航空宇宙センター(JAXA)(CAC)), 調布市, 東京我々は、ISS-JEM（国際宇宙ステーション・日本実験棟）曝露部上での微生物と生命材料となり得る有機化合物の天体間の移動の可能性の検討と微小隕石の検出および解析実験を提案し［たんぽぽ：有機物・微生物の宇宙曝露と宇宙塵・微生物の捕集］、その準備を進めている。超低密度エアロゲルを長期間（1年以上）曝露し、惑星間塵や宇宙デブリを含む微粒子を捕集するとともに、新規に開発したエアロゲルの利用可能性を検証する。捕集された微粒子とそれが形成する衝突痕（トラック）に対して、微生物または微生物関連生体高分子（DNA等）や有機物の検出、解析を行う。また、微生物を宇宙曝露する事により、微生物の宇宙環境での生存可能性と、生存に影響を与える環境因子について、推定を行う。また、宇宙塵に含まれて地球に飛来する有機物が宇宙空間で変成する可能性を検討する。本発表では、本計画の概要と現時点での準備状況等について報告する。著者人数: 16名形態: カラー図版あり資料番号: AA1530025047
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宇宙環境利用シンポジウム 第29回： 平成26年度 = Space Utilization Research, Vol. 29 2014: Proceedings of The Twenty-ninth Space Utilization Symposium 29 29-30 2015年1月第29回宇宙環境利用シンポジウム (2015年1月24日-25日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県 Space Utilization Research (January 24-25, 2015. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan 著者人数: 12名 資料番号: SA6000035015 レポート番号: ISAS-SUR29-S10
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日本地球惑星科学連合大会予稿集(Web) 2015 ROMBUNNO.BAO01‐05 (WEB ONLY) 2015年
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2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, ANIMMA 2015 2015年© 2015 IEEE. We have been developing a submillimeter resolution and low-cost DOI-PET detector using wavelength shifting fibers (WLSF), scintillating crystal plates and MPPCs (Hamamatsu Photonics). Conventional design of DOI-PET detectors had approximately mm3of resolution by using some scintillating blocks with a volume of 1 mm3, which detects gamma-ray. They are expensive due to difficulties in processing scintillating crystals and a large number of photo-detectors, and these technologies are likely to reach the limit of the resolution. Development of a lower cost DOI-PET detector with higher resolution is challenging to popularize the PET diagnosis. We propose two type of PET detector. One is a whole body PET system, and the other is a pet system for brain or small animals. Each PET system consists 6 blocks. The former consists of 6 layers of crystal plates with 300 mm × 300 mm × 4 mm. The latter consists of 16 crystal layers, forming 4 × 4 crystal arrays. The size of the crystal plate is 40 mm × 40 mm × 1 mm. Wavelength shifting fiber (WLSF) sheets are attatched to above and up and down side of crystal planes. The whole PET system has 8 MPPCs attached on each side. For the brain PET detector, 9 WLSF fibers are attached on the each side. The expected position resolution would be less than 1 mm at the former system. We have performed an experimental performance estimation for the system component using22Na radioactive source. We achieved a collection efficiency of 10% using the WLSF sheet and Ce:Gd3(Al, Ga)5O12(GAGG) crystals at 511 keV. The linear relationship between reconstruction position and incident position was obtained, and a resolution of 0.7 mm (FWHM) for x-axis of DOI by the WLSF readout was achieved.
共同研究・競争的資金等の研究課題
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