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会議情報: 第14回宇宙環境シンポジウム (2017年11月6日-35日. 神戸大学先端融合研究環統合研究拠点コンベンションホール), 神戸市, 兵庫県, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

会議情報: 第14回宇宙環境シンポジウム (2017年11月6日-33日. 神戸大学先端融合研究環統合研究拠点コンベンションホール), 神戸市, 兵庫県, 形態: カラー図版あり, Physical characteristics: Original contains color illustrations

By irradiating an electron beam to the insulating materials, it is thought that electron-hole pairs are generated inside the sample. However, there is no reported cases about this problem. Therefore, by using a blocking layer to block the charge injection from the outside, an inside of an irradiated sample electron-hole pairs was investigated whether it is produced in the DC stress., 会議情報: 第12回 宇宙環境シンポジウム（2015年11月16日-18日. 北九州国際会議場 国際会議室）, 北九州市, 福岡県, 形態: カラー図版あり, Meeting Information: The 12th Spacecraft Environment Symposium (November 16-18, 2015. International Conference Room, Kitakyushu International Conference Center), Kitakyushu, Fukuoka, Japan, Physical characteristics: Original contains color illustrations

By irradiating an electron beam to the insulating materials, it is thought that electron-hole pairs are generated inside the sample. However, there is no reported cases about this problem. Therefore, by using a blocking layer to block the charge injection from the outside, an inside of an irradiated sample electron-hole pairs was investigated whether it is produced in the DC stress., 会議情報: 第12回 宇宙環境シンポジウム（2015年11月16日-18日. 北九州国際会議場 国際会議室）, 北九州市, 福岡県, 形態: カラー図版あり, Meeting Information: 12th Spacecraft Environment Symposium (November 16-18, 2015. International Conference Room, Kitakyushu International Conference Center), Kitakyushu, Fukuoka, Japan, Physical characteristics: Original contains color illustrations

会議情報: 第12回 宇宙環境シンポジウム（2015年11月16日-18日. 北九州国際会議場 国際会議室）, 北九州市, 福岡県, 形態: カラー図版あり, Meeting Information: The 12th Spacecraft Environment Symposium (November 16-18, 2015. International Conference Room, Kitakyushu International Conference Center), Kitakyushu, Fukuoka, Japan, Physical characteristics: Original contains color illustrations

会議情報: 第11回宇宙環境シンポジウム (2014年12月10日-11日. 大阪府立大学 I-siteなんば), 大阪, 形態: カラー図版あり, Meeting Information: 11th Spacecraft Environment Symposium (December 10-11, 2014. I-site Namba, Osaka Prefecture University), Osaka, Japan, Physical characteristics: Original contains color illustrations

会議情報: 第11回宇宙環境シンポジウム (2014年12月10日-11日. 大阪府立大学 I-siteなんば), 大阪, 形態: カラー図版あり, Meeting Information: 11th Spacecraft Environment Symposium (December 10-11, 2014, I-site Namba, Osaka Prefecture University), Osaka, Japan, Physical characteristics: Original contains color illustrations

Recently, satellite anomaly is mainly caused by charging and discharging. It is important to check the charging hazard in the satellite development phase. There are some charging analysis code such as NASCAP, but the latest version of NASCAP is not available in Japan because of the export license limitation in USA. So we started the development of charging analysis tool called MUSCAT (Multiutility Spacecraft Charging Analysis Tool). MUSCAT will be used to evaluate the risk of charging and discharging hazard not only at the development phase but also at satellite operation in LEO, PEO and GEO. Development plan and current status is reported., JAXA Special Publication, 宇宙航空研究開発機構特別資料

形態: カラー図版あり, 会議情報: 第7回宇宙環境シンポジウム (2010年10月19日-20日. 東京国際フォーラム), Original contains color illustrations, Meeting Information: 7th Spacecraft Enivironment Symposium (October 19-20, 2010, Tokyo International Forum), Tokyo Japan

形態: カラー図版あり, 会議情報: 第10回宇宙環境シンポジウム (2013年12月2日-3日. 科学技術館), 東京, Physical characteristics: Original contains color illustrations, Meeting Information: 10th Spacecraft Environment Symposium (December 2-3, 2013, Science Museum), Tokyo Japan

For determination of dielectric volume resistivty under space environment, it is important to understand the effect of test pammeters such as electron energy and sample temperature. In this paper, the effect of sample thickness, electron irradiation energy and temperature on volume resistivity is analyzed by the charge storage method. The dielectric material considered here is typical polyimide(Kapton) film. The experimental results indicate that higher electron energy and thinner sample thickness show lower resistivity. Higher temperatur also exhibits lower ressistivity according to the Boltzmann type resistivity decrease., Original contains color illustrations, Meeting Information: 7th Spacecraft Enivironment Symposium (October 19-20, 2010, Tokyo International Forum), Tokyo Japan, 形態: カラー図版あり, 会議情報: 第7回宇宙環境シンポジウム (2010年10月19日-20日. 東京国際フォーラム)

形態: カラー図版あり, 会議情報: 第10回宇宙環境シンポジウム (2013年12月2日-3日. 科学技術館), 東京, Physical characteristics: Original contains color illustrations, Meeting Information: 10th Spacecraft Environment Symposium (December 2-3, 2013, Science Museum), Tokyo Japan

Two dimensional dynamic surface discharge phenomena have been investigated using an electro-optical Pockels effect with a flat red-light source of LED (Light Emitting Diode) array. To make clear the surface condition damaged due to the cosmic ray such as high energy electrons, photon and gamma ray, etc., the size of electro optical measurement system should be down to less than 70 mm cubic and the pressure inside the vessel also should be reduced less than atmosphere pressure. We have experimentally studied the dynamic surface discharge phenomena on a BSO crystal or some high molecular insulating film (Polyimide, Polyethylene terephthalate and Polyvinylidene-fluoride) with the HVC (High-speed Video Camera) under the ac peak voltage of 5 kV during one cycle at the pressures of 21 to 101 kPa. From this work, it is found that the pattern obtained by the negative discharge was always a concentric circle, which is caused by the electron emission from the needle electrode. On the other hand, the pattern of positive streamer has characteristic shape that depends on the kind of insulating material. These results show that the propagation of positive streamer is influenced by photoelectric effect from insulating film., Original contains color illustrations, Meeting Information: 6th Spacecraft Enivironment Symposium (February 29-30, 2009. Kitakyushu International Conference Center), 形態: カラー図版あり, 会議情報: 第6回宇宙環境シンポジウム (2009年2月29日-30日. 北九州国際会議場)

The purpose of this study is to build and validate a model of volume resistivity from the experimental results to analyze the influence of parameters such as electron beam energy and sample temperature. We established a measurement setup, called the charge storage method, which measures volume resistivity by analyzing the time history of a dielectric devices to investigate volume resistivity in the temperature range attained (from 260K to 320K). In this paper, we measured the volume resistivity. We analyzed the effect of sample thickness, electron beam irradiation energy and temperature. The dielectric material considered here is typical polyimide (Kapton(Reg. U.S.Pat. & Tm. Off.)) film. The experimental results indicate that higher electron energy and thinner sample thickness show lower resistivity .volume resistivity in dark current region decreases theoretically as the sample temperature increases. Moreover, we proposed the mechanism of charge accumulation in charge storage method., Physical characteristics: Original contains color illustrations, Meeting Information: 8th Spacecraft Enivironment Symposium (October 18-19, 2011, Tokyo Big Sight), Tokyo Japan, 形態: カラー図版あり, 会議情報: 第8回宇宙環境シンポジウム (2011年10月18-19日. 東京国際展示場), 東京

形態: カラー図版あり, 会議情報: 第5回宇宙環境シンポジウム(2008年12月18日-12月19日. つくば国際会議場）

The spacecraft like a communication or a broadcasting satellite flying in GEO (Geostationary Orbit) is always exposed to plasma and/or radioactive-rays such as α-, β-, and γ-rays. When the insulating materials, in which the spacecraft is wrapped to keep temperature in it stable, are irradiated by the high energy proton beam, sometimes an unexpected accident due to an electrostatic discharge occurs. However, it has not known how the irradiation affects to change of the electrical properties of the materials. In our previous research work, we especially focused on an internal charging phenomenon which must affect to the electrical properties of irradiated polyimide for spacecraft. Judging from the measurement results, it is found that a positive charge accumulates in polyimide rapidly up to a certain saturated value, then it gradually decreases even during the proton beam irradiation. As the reason for the phenomenon, we consider the generation of RIC (Radiation Induced Conductivity). In this paper, we tried to measure the space charge distribution and conduction current under DC stress of 100 kV/mm in proton beam irradiated different type of Polyimides to figure out the mechanism of RIC., 会議情報: 第9回宇宙環境シンポジウム (2012年11月5日-6日. 東京都市大学・世田谷キャンパス), 東京, 形態: カラー図版あり, Meeting Information: 9th Spacecraft Enivironment Symposium (November 5-6, 2012, Setagaya Campus, Tokyo City University), Tokyo Japan, Physical characteristics: Original contains color illustrations

We studied how to measure the secondary electron emission (SEE) of metal and insulating materials used for satellite thermal insulation or other such purposes. SEE yield measurement is very important for analyzing charge accumulation on the satellite surfaces due to the space environment because electron emission for irradiated electrons influences the amount of surface charge. Therefore, we are developing the measurement system without the deceleration voltage and enable to obtain the characteristics of the SEE yield from insulation materials irradiated by an electron beam with energy of 200 eV to 10 keV. This report introduces the developed measurement system and the SEE yield measurement results of metal sample and polymer. From those results, we discuss the characteristics of SEE that depend on each material. Furthermore, we also propose a future plan of SEE measurement for satellite materials., 会議情報: 第9回宇宙環境シンポジウム (2012年11月5日-6日. 東京都市大学・世田谷キャンパス), 東京, 形態: カラー図版あり, Meeting Information: 9th Spacecraft Enivironment Symposium (November 5-6, 2012, Setagaya Campus, Tokyo City University), Tokyo Japan, Physical characteristics: Original contains color illustrations

Spacecraft sometimes have a serious damage due to the electro static discharge accident. It is said that the charge accumulation in dielectric materials on spacecraft irradiated by high energy charged particles in space environment causes the discharge accident. Therefore, we need to investigate the charge accumulation characteristics in the bulk of dielectric materials. We have been developing a system for measuring internal charge distribution in dielectric materials using Pulsed Electro-Acoustic (PEA) method. Using the system, we tried to measure the charge distribution after proton beam irradiated polyimide (PI) film, which has been used as a thermal control layer of spacecraft. From the result, it is found that positive charge accumulates in PI film rapidly up to a certain saturated value, then it gradually decreases during the proton beam irradiation. As the reason for the phenomenon, we consider the RIC (Radiation Induced Conductivity) by proton beam. In this paper, we show the typical charge distribution under proton beam irradiation and the conductivity in PI irradiated by proton beam. As the result, it is found that the relationship of decrease processes in amount of positive charge and RIC., Physical characteristics: Original contains color illustrations, Meeting Information: 8th Spacecraft Enivironment Symposium (October 18-19, 2011, Tokyo Big Sight), Tokyo Japan, 形態: カラー図版あり, 会議情報: 第8回宇宙環境シンポジウム (2011年10月18-19日. 東京国際展示場), 東京

形態: カラー図版あり, 会議情報: 第10回宇宙環境シンポジウム (2013年12月2日-3日. 科学技術館), 東京, Physical characteristics: Original contains color illustrations, Meeting Information: 10th Spacecraft Environment Symposium (December 2-3, 2013, Science Museum), Tokyo Japan

The purpose of our research work is to develop a compact bulk charge measurement system and to measure the charge distribution under proton-beam irradiated dielectric materials used for spacecraft. Spacecrafts sometimes have a serious damage due to the electrostatic discharge accident. It is said that the charge accumulation in dielectric materials irradiated by high energy particles in space environment causes the discharge accident. However, there remain many unknown factor about a charge accumulation in dielectric materials by irradiation of charged particle. Therefore, we need to measure the charge distribution in the bulk of dielectric materials. We have had many experiences to measure the charge distribution in dielectric materials under electron-beam irradiation. However, there are few measurement results of the proton-beam irradiated samples and we have to carry out a proton-beam irradiation in specially arranged equipment for proton beam irradiation. Therefore, we have been developing a compact bulk charge measurement apparatus for applying to several measurement environments in various irradiation chamber., 形態: カラー図版あり, 会議情報: 第5回宇宙環境シンポジウム(2008年12月18日-12月19日. つくば国際会議場）

Spacecraft are charged under plasma environment and radiation environment in space, and it may lead failures and anomalies of spacecraft when discharge on the spacecraft surface occurs. One of the most important surface materials is cover glass for solar-cells which is a source of an electrical power. The purpose of this paper is to investigate surface-potential characteristics of coverglasses with coatings after electron irradiation. We found that the surface potential on coverglasses becomes positive within a few hours after irradiation. Comparing the surface potential histories of coated coverglass and silica glass revealed that the positive potential of coverglass is due to ionization of metallic atoms in surface coating material. The positive potential is relaxed over several days which will increase a risk of discharge. We conclude it is necessary to select coating materials with lower secondary emission coefficient., 会議情報: 第9回宇宙環境シンポジウム (2012年11月5日-6日. 東京都市大学・世田谷キャンパス), 東京, 形態: カラー図版あり, Meeting Information: 9th Spacecraft Enivironment Symposium (November 5-6, 2012, Setagaya Campus, Tokyo City University), Tokyo Japan, Physical characteristics: Original contains color illustrations

The purpose of our research work is to measure the space charge distribution in proton beam irradiated dielectric materials for spacecrafts. Spacecrafts sometimes have a serious damage due to the electro static discharge accident. It is said that the charge accumulation in dielectric materials irradiated by high energy charged particles in space environment causes the discharge accident. Therefore, we need to measure the charge distribution in the bulk of dielectric materials. We have been developing a system for measuring internal charge distribution in dielectric materials using Pulsed Electro-Acoustic (PEA) method. Using the system, we tried to measure the charge distribution after proton beam irradiated polyimide (PI) and fluorinated ethylene propylene copolymer (FEP) films which have been used as a thermal control layers or an optical solar reflector of spacecrafts. From the result, it is found that positive charges accumulate in bulk of PI and FEP films after proton beam irradiation of the proton beams. However, the amounts of accumulated positive charge in PI increase with increase of irradiation time, while those in FEP decrease. Therefore, it is found that the charge accumulation properties strongly depend on the kinds of irradiated materials., Original contains color illustrations, Meeting Information: 6th Spacecraft Enivironment Symposium (February 29-30, 2009. Kitakyushu International Conference Center), 形態: カラー図版あり, 会議情報: 第6回宇宙環境シンポジウム (2009年2月29日-30日. 北九州国際会議場)