Application Of NaI EDS In The Measurement Of Activity Of Radioactive Material In Nuclear Accident

The nuclear power has been found for half century, it gives both many resources and environmental pollutions. Initially nuclear tests are generally conducted on the ground. A large number of radioactive substances pollute the environment. Although the testing of nuclear weapons has been greatly reduced, the new problem has cropped up. With the intensification of the energy shortage, the number of nuclear power plants is becoming more and more. Using of nuclear energy threat to people’s lives. Japan’s Fukushima nuclear power plant accident caused a leak of radioactive substances in 2011. 137 Cs and 134 Cs radionuclide pollute the surrounding environment. Food security is facing serious challenges. The traditional instrument for low activity of the substance is difficult to qualitative and quantitative analysis. The application of more advanced HPGe spectrometer are restricted due to its high priices and harsh using environment.subject to certain.The paper researched domestic and foreign EDS used for measurement of radioactivity and related methods of spectrometer measurement techniques. Combined with the results of previous studies, sodium iodide scintillation crystals as detectors fixed practical application of nuclear energy spectrometer were explored. This instrument was used as a lead chamber 5cm thickness measurement chamber. Background counts in the air were about 250 cpm, the water background count were about 315 cpm. There was better shielding to improve the detection limit of the instrument. Article used a five-point least squares fitting instrument linear energy scale, ensuring low energy havd a good linearity with high-energy radiation. MCNP software used spectroscopy to measure the actual substances of radioactivity simulation, optimization of the instrument detection efficiency. Under the same conditions, the detection efficiency was improved by nearly 20%. The MCNP simulation results proved relatively accurate through actual measurement,.First, author assembled and debugged spectrometer. It was guaranteed to have good energy resolution and energy linear. A five-point scale was used by linear energy method. aThe γ spectrum was measured with a statistical fluctuation of γ spectral shape due to statistical fluctuation and electronic noise. Authorsmoothed γ spectra by three methods and analyzed the results. It included three points gravity method, moving least squares smoothing, Gaussian low-pass filtering. Gaussian fitting characteristic peaks were fitted by the least square method and quintet decomposition. In this paper, the characteristic peak inverse matrix method and the least squares method was used to calculate the corresponding radionuclide activity. Two calculation methods for comparison, the theoretical peaks relatively poor inverse matrix method was more suitable for 137 Cs, 134 Cs, 40 K activity for quantitative analysis.