In a deuterium operation on the Large Helical Device, the measurement and control equipment placed in the toms hall must survive under an environment of radiation, To study the effects of gamma-ray irradiation on the ...In a deuterium operation on the Large Helical Device, the measurement and control equipment placed in the toms hall must survive under an environment of radiation, To study the effects of gamma-ray irradiation on the equipment, an irradiation experiment is performed at the Cobalt-60 irradiation facility of Nagoya University. Transient and permanent effects on a personal computer, media converters, programmable logic controllers, isolation amplifiers, a web camera, optical flow meters, and water sealing gaskets are experimentally surveyed. Transient noise appears on the web camera. Offset of the signal increases with an increase of the integrated dose on the programmable logic controller. The DeviceNet module on the programmable logic controller is broken at the integrated dose of 72 Gy, which is the expected range of the integrated dose of the toms hall. The other equipment can survive under the gamma-ray field in the toms hall.展开更多
Objective To study the effects of gamma-ray irradiation on carbon fixation (Specific production rate: SPR), CO2 utilization efficiency (CUE) and electron transfer rate (ETR) in the photosynthetic flagellate Euglena g...Objective To study the effects of gamma-ray irradiation on carbon fixation (Specific production rate: SPR), CO2 utilization efficiency (CUE) and electron transfer rate (ETR) in the photosynthetic flagellate Euglena gracilis strain Z in a dose-response dependent manner. Methods Euglena cells were cultured in an inorganic nutrient medium containing ammonium chloride or proteose peptone. Cells were exposed to gamma-ray at 5 doses (0, 100, 250, 350, 500 Gy for water). Five days after irradiation, three photosynthetic activities were measured. SPR, which is a carbon uptake rate per unit carbon mass, was determined by 13C tracer methodology. CUE was evaluated using a relation of carbon isotope fractionation in Calvin cycle. ETR in photosystem II (PS II) was measured by a chlorophyll fluorescence analysis. Results Even at a dose of 500 Gy, 80 % of ETR of the non-irradiated control (0 Gy) was sustained, while SPR and CUE were about half the level in the non-irradiated control at 500 Gy. Furthermore, the dose response of ETR was considerably different from the others. Conclusion Our findings suggest that not only PS II but also the Calvin cycle in the photosynthetic system is affected by gamma ray irradiation.展开更多
Paul Scherrer Institut hosts the Proton Irradiation Facility used for radiation effects studies and exposure tests in preparation of satellite missions for the European Space Agency. The facility allows for realistic ...Paul Scherrer Institut hosts the Proton Irradiation Facility used for radiation effects studies and exposure tests in preparation of satellite missions for the European Space Agency. The facility allows for realistic simulation of the space proton spectra in the energy range from 6 MeV up to 230 MeV with exposure fluxes ranging from very low up to as high as 109 p/cm2/sec. Recently, approved ESA mission to Jupiter—JUICE—also brought a need for tests with high energy electron beams. For this purpose, another facility was established in the PSI secondary beam area piM1. Secondary particles are produced on the thick carbon target hit by energetic proton beam. Dedicated beam optics enables selection of the particle charge and momentum and guides them to the tests area. Characterization of electron beams at various momenta was performed with respect to their intensity, profiles and contamination by pions and muons. Electron fluxes ranging from 1.5 × 103/cm2/s at 20 MeV/c to 2.3 × 106/cm2/s at 345 MeV/c with gaussian beam profiles with FWHM of about 4 cm were measured. Beam contamination with heavier particles becomes negligible for all momenta lower than 115 MeV/c. This allows for using them for components and shielding characterization and detector calibration experiments. Several such experiments have been already performed utilizing available beam time of few weeks per year.展开更多
Lateral type n-channel 4H-SiC metal–oxide–semiconductor field effect transistors(MOSFETs),fabricated using a current industrial process,are irradiated with gamma rays at different irradiation doses in this paper to ...Lateral type n-channel 4H-SiC metal–oxide–semiconductor field effect transistors(MOSFETs),fabricated using a current industrial process,are irradiated with gamma rays at different irradiation doses in this paper to carry out a profound study on the generation mechanism of radiation-induced interface traps and oxide trapped charges.Electrical parameters(e.g.,threshold voltage,subthreshold swing and channel mobility)of the device before and after irradiation are investigated,and the influence of the channel orientation([1100]and[1120])on the radiation effect is discussed for the first time.A positive threshold voltage shift is observed at very low irradiation doses(<100 krad(Si));the threshold voltage then shifts negatively as the dose increases.It is found that the dependence of interface trap generation on the radiation dose is not the same for doses below and above 100 krad.For irradiation doses<100 krad,the radiation-induced interface traps with relatively high generation speeds dominate the competition with radiation-induced oxide trapped charges,contributing to the positive threshold voltage shift correspondingly.All these results provide additional insight into the radiation-induced charge trapping mechanism in the SiO_(2)/SiC interface.展开更多
Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering ...Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser ab-sorption and scattered light were about 90% and 10%,respectively,under focusing irradiation,but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of fo-cusing irradiation,the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity,X-ray conversion increased. This is highly advantageous to the in-ertial confinement fusion. However,X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irra-diation was basically the same.展开更多
基金supported partly by the LHD project budget(NIFS15ULHH003 and NIFS15ULGG801)
文摘In a deuterium operation on the Large Helical Device, the measurement and control equipment placed in the toms hall must survive under an environment of radiation, To study the effects of gamma-ray irradiation on the equipment, an irradiation experiment is performed at the Cobalt-60 irradiation facility of Nagoya University. Transient and permanent effects on a personal computer, media converters, programmable logic controllers, isolation amplifiers, a web camera, optical flow meters, and water sealing gaskets are experimentally surveyed. Transient noise appears on the web camera. Offset of the signal increases with an increase of the integrated dose on the programmable logic controller. The DeviceNet module on the programmable logic controller is broken at the integrated dose of 72 Gy, which is the expected range of the integrated dose of the toms hall. The other equipment can survive under the gamma-ray field in the toms hall.
文摘Objective To study the effects of gamma-ray irradiation on carbon fixation (Specific production rate: SPR), CO2 utilization efficiency (CUE) and electron transfer rate (ETR) in the photosynthetic flagellate Euglena gracilis strain Z in a dose-response dependent manner. Methods Euglena cells were cultured in an inorganic nutrient medium containing ammonium chloride or proteose peptone. Cells were exposed to gamma-ray at 5 doses (0, 100, 250, 350, 500 Gy for water). Five days after irradiation, three photosynthetic activities were measured. SPR, which is a carbon uptake rate per unit carbon mass, was determined by 13C tracer methodology. CUE was evaluated using a relation of carbon isotope fractionation in Calvin cycle. ETR in photosystem II (PS II) was measured by a chlorophyll fluorescence analysis. Results Even at a dose of 500 Gy, 80 % of ETR of the non-irradiated control (0 Gy) was sustained, while SPR and CUE were about half the level in the non-irradiated control at 500 Gy. Furthermore, the dose response of ETR was considerably different from the others. Conclusion Our findings suggest that not only PS II but also the Calvin cycle in the photosynthetic system is affected by gamma ray irradiation.
文摘Paul Scherrer Institut hosts the Proton Irradiation Facility used for radiation effects studies and exposure tests in preparation of satellite missions for the European Space Agency. The facility allows for realistic simulation of the space proton spectra in the energy range from 6 MeV up to 230 MeV with exposure fluxes ranging from very low up to as high as 109 p/cm2/sec. Recently, approved ESA mission to Jupiter—JUICE—also brought a need for tests with high energy electron beams. For this purpose, another facility was established in the PSI secondary beam area piM1. Secondary particles are produced on the thick carbon target hit by energetic proton beam. Dedicated beam optics enables selection of the particle charge and momentum and guides them to the tests area. Characterization of electron beams at various momenta was performed with respect to their intensity, profiles and contamination by pions and muons. Electron fluxes ranging from 1.5 × 103/cm2/s at 20 MeV/c to 2.3 × 106/cm2/s at 345 MeV/c with gaussian beam profiles with FWHM of about 4 cm were measured. Beam contamination with heavier particles becomes negligible for all momenta lower than 115 MeV/c. This allows for using them for components and shielding characterization and detector calibration experiments. Several such experiments have been already performed utilizing available beam time of few weeks per year.
基金the National Natural Science Foundation of China(Grant Nos.52107190 and 62101181)China Postdoctoral Science Foundation(Grant No.2021M700203)。
文摘Lateral type n-channel 4H-SiC metal–oxide–semiconductor field effect transistors(MOSFETs),fabricated using a current industrial process,are irradiated with gamma rays at different irradiation doses in this paper to carry out a profound study on the generation mechanism of radiation-induced interface traps and oxide trapped charges.Electrical parameters(e.g.,threshold voltage,subthreshold swing and channel mobility)of the device before and after irradiation are investigated,and the influence of the channel orientation([1100]and[1120])on the radiation effect is discussed for the first time.A positive threshold voltage shift is observed at very low irradiation doses(<100 krad(Si));the threshold voltage then shifts negatively as the dose increases.It is found that the dependence of interface trap generation on the radiation dose is not the same for doses below and above 100 krad.For irradiation doses<100 krad,the radiation-induced interface traps with relatively high generation speeds dominate the competition with radiation-induced oxide trapped charges,contributing to the positive threshold voltage shift correspondingly.All these results provide additional insight into the radiation-induced charge trapping mechanism in the SiO_(2)/SiC interface.
文摘Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser ab-sorption and scattered light were about 90% and 10%,respectively,under focusing irradiation,but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of fo-cusing irradiation,the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity,X-ray conversion increased. This is highly advantageous to the in-ertial confinement fusion. However,X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irra-diation was basically the same.
