A novel simple method based on pulse area analysis （PAA） is presented for acquisition of nuclear spectra by a digitizer. The PAA method can be used as a substitute for the traditional method of pulse height analysis...A novel simple method based on pulse area analysis （PAA） is presented for acquisition of nuclear spectra by a digitizer. The PAA method can be used as a substitute for the traditional method of pulse height analysis （PHA）. In the PAA method a commercial digitizer was employed to sample and sum in the pulse, and the area of the pulse is proportional to the energy of the detected radiation. The results of simulation and experiment indicate the great advantages of the PAA method, especially as the count rate is high and the shaping time constant is small. When the shaping time constant is 0.5 μs, the energy resolution of PAA is about 66% better than that of PHA.展开更多
A soft x-ray Pulse Height Analysis (PHA) diagnostic with the recently introduced Silicon Drift Detector (SDD) and a new MCA system has been installed in HT-7 for the measurements of electron temperature. With the SDD ...A soft x-ray Pulse Height Analysis (PHA) diagnostic with the recently introduced Silicon Drift Detector (SDD) and a new MCA system has been installed in HT-7 for the measurements of electron temperature. With the SDD detector, the x-ray emission can be detected in the energy range from 1 keV up to 20 keV. The extremely low anode capacity of SDD allows very high counting rates of x-ray above 200 kHz and short shaping times below 0.25 μs to be measurede. In routine operation a counting rate of 120 kHz has been normally obtained with an energy resolution of better than 180 eV at 5.9 keV. The assembly is equipped with six SDD detectors measuring the soft x-ray emission integrated along six chords of the upper half plasma cross section. The preliminary results from the new soft x-ray PHA diagnostic are also presented in this paper.展开更多
Alpha spectrometry using pulse height analysis has been used for the determination of uranium concentrations in different environmental samples. The concentration of 238U was measured by both destructive and non-destr...Alpha spectrometry using pulse height analysis has been used for the determination of uranium concentrations in different environmental samples. The concentration of 238U was measured by both destructive and non-destructive techniques with a detection limit of less than 1.8 mBq/kg. However, because of the extremely low 234U concentrations in environmental samples, it was necessary to use a destructive technique to separate U from the sample matrices as well as remove interfering elements from the sample solution to determine 238U/234U ratio. In this study, the uranium was separated from the environmental samples using anion exchangers in (Dowex 1 × 8 Cl? form) and purified via co-precipitation with Lanthanum fluorides (LaF3) and the alpha source prepared by electrodeposition. The results obtained were validated using some certified reference samples.展开更多
基金Supported by National Natural Science Foundation of China(11375077,11027508)
文摘A novel simple method based on pulse area analysis （PAA） is presented for acquisition of nuclear spectra by a digitizer. The PAA method can be used as a substitute for the traditional method of pulse height analysis （PHA）. In the PAA method a commercial digitizer was employed to sample and sum in the pulse, and the area of the pulse is proportional to the energy of the detected radiation. The results of simulation and experiment indicate the great advantages of the PAA method, especially as the count rate is high and the shaping time constant is small. When the shaping time constant is 0.5 μs, the energy resolution of PAA is about 66% better than that of PHA.
基金The project supported by the National Natural Science Foundation of China (Nos. 10305012, 10375070)
文摘A soft x-ray Pulse Height Analysis (PHA) diagnostic with the recently introduced Silicon Drift Detector (SDD) and a new MCA system has been installed in HT-7 for the measurements of electron temperature. With the SDD detector, the x-ray emission can be detected in the energy range from 1 keV up to 20 keV. The extremely low anode capacity of SDD allows very high counting rates of x-ray above 200 kHz and short shaping times below 0.25 μs to be measurede. In routine operation a counting rate of 120 kHz has been normally obtained with an energy resolution of better than 180 eV at 5.9 keV. The assembly is equipped with six SDD detectors measuring the soft x-ray emission integrated along six chords of the upper half plasma cross section. The preliminary results from the new soft x-ray PHA diagnostic are also presented in this paper.
文摘Alpha spectrometry using pulse height analysis has been used for the determination of uranium concentrations in different environmental samples. The concentration of 238U was measured by both destructive and non-destructive techniques with a detection limit of less than 1.8 mBq/kg. However, because of the extremely low 234U concentrations in environmental samples, it was necessary to use a destructive technique to separate U from the sample matrices as well as remove interfering elements from the sample solution to determine 238U/234U ratio. In this study, the uranium was separated from the environmental samples using anion exchangers in (Dowex 1 × 8 Cl? form) and purified via co-precipitation with Lanthanum fluorides (LaF3) and the alpha source prepared by electrodeposition. The results obtained were validated using some certified reference samples.
