One Kind Of γ Detection Efficiency Calibration Method And Its Application In The Analysis Of Radionuclide Activity

Measurement and analysis of y-ray spectroscopy is one of the basic methods of the type and activity of radionuclide analysis with y radiation, in terms of radioactivity analysis, radioactivity measurements and scientific research have a wide range of applications. Environmental monitoring and protection, by y-ray energy and intensity measurements of radionuclide, the sample can be determined only if there is contamination, and can determine the composition and content of contaminants in environmental and human health are of great significance. In the energy spectrum measurement and analysis y spectrometer, we need to know spectrometer detection efficiency for particular y-ray detection efficiency is the Almighty peak count on some energy y-ray spectrum and source emission the ratio of the number of colors of rays. We determined when measuring spectrometer detection efficiency is a key activity of radionuclide analysis. To determine the spectrometer detection efficiency, it is necessary before the efficiency calibration measurements, namely the establishment of the correspondence between the activity of the sample and the detector counts. At present, the efficiency of the scale there are two main ways:one is a reference source of law, the other is passive efficiency calibration method. Reference source method requires data on the y detection efficiency calibration curve fitting. Detection efficiency curve fitting equation, there are many:such interpolation fitting, the natural logarithm of the energy efficiency of the linear natural numbers fit the natural logarithm of the energy efficiency of the natural logarithm of the quadratic fit to the efficiency of the natural logarithm energy polynomial fitting. These methods generally y spectrum analysis software is often used, for example, Gamma Vision32software. These methods are based on the least squares method is purely mathematical approach, there is no actual physical meaning.This paper describes an almighty peak efficiency curve fitting formula, the formula for the fitting parameters is linear, the probability of the y-ray interaction with matter (mainly photoelectric absorption, Compton scattering and electron pair production) With gradual changes in the relationship between the expression of y-ray energy incident resulting in a number of patchwork, this formula can be on a relatively wide energy region a good fit Almighty peak efficiency purity germanium (HPGe) detector curve. With y spectrometer detector is a series of high-purity germanium detector samples were measured to obtain the detection efficiency of different energy y-rays. Then utilization based on Lab VIEW platform programming with language G, respectively, fitting the proposed energy peak efficiency curve fitting formula and the natural logarithm of the enertoo both of these methods in the detection efficiency curve fitting pros and cons. After calculating we know that the method in this paper has higher accuracy than the natural logarithm of the energy efficiency of polynomial fitting in some energy y-ray detection efficiency.Under both the detection of efficiency fitting formula, were calculated radionuclide activity of the sample, and then the use of radionuclide activity y spectrometer measurements were compared. We have chosen instrument of ORTEC’s purity germanium spectrometer, application software comes with Gamma Vision32. After a series of measurements and calculations, methods in this paper compares with y spectrometer measured results.The relative error is less than5%, basically meet the requirements of radionuclide activity measurements. This reflects the breadth of the proposed method is reasonable and applications. Therefore, the method of this paper can be used to measure radionuclide.