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Space charge accumulation characteristics in Epoxy resin with various heat treatments were investigated under DC high stress using as pulsed-electro acoustic (PEA) method. Epoxy resin has been used as sealing material for semiconductor devices. Recently, a new semiconductor like silicon carbide (SiC) has been developed to use it at high temperature environment. However, the conventional epoxy resin...
Space charge accumulation and conduction current in low density polyethylene (LDPE) incuding cumylalcohol under dc high electric field were investigated using improve PEA (pulsed electro-acoustic) measurement system. In the bulk of XLPE that is being used for power transmission cables, there remain some chemical residues of crosslinking by-products such as α-methylstyrene, acetophenone and cumylalcohol...
We have investigated the space charge distribution in low density polyethylene (LDPE). Under high dc electric field, a huge amount of positive packet like charge is observed in LDPE. It moves towards the counter electrode under high dc electric field, and then the breakdown finally occurs. The reason of the generation of the packet like charge is thought that there are two different conductivity in...
Oil-paper compound insulation has been widely used in power transformers for quite a long time because of its good performance. The paper insulation degrades under the combined stresses of thermal, electrical and chemical stresses during routine operations, resulting in the reduction of its degree of polymerization (DP) and hence its mechanical and electrical strength. Space charges in a dielectric...
The purpose of our research work is to evaluate some electrical properties of electron beam irradiated insulating materials for spacecraft. 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...
We evaluate the dielectric characteristic of polymeric materials for MLI (Multi Layer Insulator, a kind of thermal insulation material) for spacecraft under high energy proton irradiation using results of space charge distribution. Spacecrafts have a serious damage due to the electro-static discharge accident. The electric charges are accumulated in the polymeric materials due to radioactive rays,...
A prototype frontend LSI for gamma-ray detectors with GEM (Gas Electron Multiplier) foils has been designed and fabricated. For reduction of number of channels and fast readout, we adopted X- and Y-strip readout method. Obtained charges are converted to digital by 10-bit 10Msps pipelined ADCs on the chip. In order that the ghost images are reduced, which are the drawback of the X- and Y-strip method,...
The purpose of our research work is to measure the space charge distribution in proton beam irradiated dielectric materials used for spacecraft. 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 particles in space environment causes the discharge accident. Therefore, we...
Charge accumulations in electron beam irradiated polymers are investigated by observing them using pressure wave propagation method. The purpose of our research work is to measure the charge distribution in electron beam irradiated dielectric materials for spacecrafts. We have been developing a system for measuring such a charge distribution in dielectric materials. Using this system, we tried to...
Charge storage properties in polymers are important phenomena to evaluate the performance of them under electron beam irradiation in such as space environment, plasma processing, electron microscopy, and so on. Authors have been developing to measure the charge distribution in polymers during the electron beam irradiation using the Pressure Wave Propagation (PWP) technique. Using the developed system,...
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