A prompt gamma neutron activation analysis setup was developed for heavy metal detection in aqueous solutions with a 300 m Ci241Am-Be neutron source and a4 4 inch(diameter height) BGO detector. In the present work, heavy metals, including Mn, Cu, Ni, Cr and Zn, were measured by the setup. The minimum detectable concentrations of Mn, Cu, Ni, Cr and Zn were 246.6, 391.2, 218.1,301.5 and 2804.1 ppm, respectively. The minimum detectable concentration of each element and the linearity response between the characteristic peak counts and elements concentrations have been studied. And the results showed that all heavy metals had a good linear relationship between characteristic peak counts and concentrations.
Can ChengDa-Qian HeiWen-Bao JiaZhou JiangHong-Tao Wang
A prompt gamma neutron activation analysis(PGNAA)set-up was developed for the elements detection in aqueous solution,which includes a 241Am-Be neutron source and a 4-inch BGO detector.The geometry of set-up is determined by a series of simulations with the MOCA code to improve the efficiency of the elements detection.The thermal neutron flux and the gamma-ray self-absorption are considered during the optimization calculations.Experiments were performed to validate the set-up using samples including chlorine and mercury,respectively.The result shows that the characteristic peak count has linear relationship with the chlorine and mercury concentration changing.The minimum detectable concentrations of chlorine and mercury were found as 54 mg/L and 51.4 mg/L,respectively.
When X-ray fluorescence （XRF） technology is used to measure the sulfur concentration in coal online, the measurement accu- racy is affected by the coal＇s uneven surface and the particle size. In order to improve the accuracy of sulfur concentration measurement, an online measurement system, consisting of a portable X-ray fluorescence instrument and an auxiliary distance correction module, was developed in this paper. By measuring the standard coal samples of known sulfur concentration, we obtained a calibration curve that can be used to analyze the sulfur concentration. We studied the relationship between the X-ray fluorescence intensity （I） and the distance （D） from surfaces to instrument. The results showed that there was a good linear re- lationship between 1 and D when the sulfur content was certain. Based on these knowledge, the distance correction formula of X-ray fluorescence intensity was proposed. By applying the distance correction formula to experimental sulfur concentration measurement, we demonstrated that the measurement accuracy can be significantly increased.
