In order to validate that the confocal X-ray fluorescence had potential applications in analyzing the intermediately and infinitely thick samples with thin sample approach without sample preparations, as an example, the confocal X-ray fluorescence based on polycapillary X-ray optics was used to analyze multi elements solutions.
A laboratory confocal micro X-ray fluorescence (micro-XRF) spectrometer based on a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel was used to carry out the size-resolved source apportionment of aerosol particles. The PPXRL in the detection channel both increased the collection angle of the detector and improved the signal-to-noise ratio of the X-ray spectrum. When this confocal micro-XRF spectrometer was used to carry out the quantitative XRF analysis of single aerosol particles with smaller size than that of the overlapping foci of the PFXRL and the PPXRL, the sensitivity was corrected by using a Gaussian function. The size-resolved “fingerprint database” for the air pollution sources was established based on the quantitative XRF results for single aerosol particles. The size-resolved aerosol particles on hazy-foggy days in Beijing were apportioned.
Objective To study thermo—luminescence characteristics of CaSO_4 phosphor doped with(Li, Dy,Tm) under different anneal condition so as to confirm the optimum temperature of anneal treatment,and to discover the relationship between temperature of anneal treatment,impurity and thermo—luminescence characteristics.Methods Three kinds of detectors,namely CaSO_4:Tm,Li,CaSO_4:Dy,Li and CaSO_4: Tm were used and annealed under 240℃,250℃,260℃,270℃,280℃,290℃and 300℃respectively in 2000 D infrared annealed oven,which were irradiated underγradiation field of ~(137)Cs(55.5 GBq) to receive the same radiation doses(0.826 mGy).RGD-3B thermo-luminescence dosimeter and Peakfit software were used in the measurement and analysis.Results Results showed that the thermo—luminescence peak of CaSO_4:Tm, Li moved toward the low temperature position as the lowering of annealing temperature.The highest peak temperature was 167℃when annealed at 300℃.When annealed at 240℃,the peak temperature was the lowest(139℃).The optimum annealing temperature was 280℃.When annealed at 300℃,the peak temperature by CaSO_4:Dy,Li was 152℃;when annealed at 260℃and 280℃,the peak temperatures were 125℃and 124℃respectively.270℃was the optimum temperature for CaSO_4:Dy,Li.There was a peak around 150℃for CaSO_4:Tm,Li luminescence curve,while for the luminescence curve of CaSO_4:Tm the thermo-luminescence peak temperature existed around 250℃,the intensity of CaSO_4:Tm,Li at high temperature was significantly higher than that of CaSO_4:Tm.Conclusions Thermo-luminescence characteristics of doped CaSO_4 phosphor is affected by the annealing temperature and closely related with the type of impurity.If the rule of impact is well mastered,the sensitivity of thermo—luminescence detector could be effectively improved,which in turn could provide a convincible experiment base in monitoring of occupational personal doses.
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