Dissertation
Dissertation > Industrial Technology > Nuclear technology > Particle detection,radiation detection and nuclear instrumentation > Radiation detection technology and instrumentation > Spectrometer > alpha , beta , gamma spectrometer

the weak gamma spectrum peaks optimization detection scheme of

Author YuanXinYu
Tutor ZhouJianLiang;LiuLiangJun
School Nanhua University
Course Nuclear Technology and Applications
Keywords gamma spectrum Wavelet Analysis Standard deviation detection filter Detecting Low
CLC TL817.2
Type Master's thesis
Year 2011
Downloads 64
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Start from the formation mechanism of the gamma spectroscopy, discussed in detail the instrument spectral peak causes. Radioactive statistical fluctuation, electronic noise, the instrument spectrum channel data are subject to statistical fluctuation in the direct analysis of the sample in the end containing Which nuclide and its exact content must spectroscopy data from this data In addition to the noise. By analysis and comparison of current spectroscopy filtering method: For laboratory spectroscopy data processing, the use of improved wavelet threshold filtering method is optimal; portable spectrometer, considering the speed of the processor to calculate, using the least squares polynomial mobile smoothing Optimal. However, the weak peak analysis filter, the peak area data filtering mostly more than 1 times the standard deviation of each channel count is greater than the statistical fluctuation, this paper proposes a 1-sigma detection filtering method. Ideal gamma-ray energy spectrum convolution program studies have shown that using this method to accurately determine the peak position and the half-width of the spectrum in addition to a constant background noise and the Peak District. 1 sigma detection filtering filter spectroscopy noise, background subtraction of the background makes the Peak District SNIP method tends to be constant, to obtain good results. Finally, the peak width discrimination to extract the heavy peak, accurate detection limit discrimination excluding the false peak interpolation method to calculate the true peak peak, the complete gamma spectroscopy weak peak optimize detection scheme design. And other two peak search algorithm, (2) the commercialization of gamma spectroscopy analysis software on 1976 IAEA peak search algorithm Detecting Low pros and cons than standard spectral analysis found, the treatment effect is not ideal. The method to distinguish between good platform and the peak of Compton, not false peak detected all 22 peaks detected peak with the standard peak offset 2.90. The scheme is applied to the spectrum of laboratory instruments, achieved good results. The experimental spectra from the building materials radon surface emanation coefficient measurement project. Of radionuclides in building materials limited standard (GB6566-2001) with internal and external exposure index to judge the level of radioactive materials, that control the content of natural radionuclides 226Ra, 232Th, 40K in building materials. Radon is a natural environment a major source of nuclear radiation on the human body, accounting for about 48% of the natural radiation. Modern living room indoor radon mainly due to precipitation of building materials, accounting for 60-70%. There is a need to be explored to optimize building materials criteria for indoor building materials, radon surface emanation coefficient. Building materials radon exhalation rate measurements are the radon surface emanation coefficient measured based on previous measuring method has some defects. Broken building materials from the radon steady-state transport equation is derived building materials surface of radon and building materials radon emanation coefficient precipitation relationship, so as to be easily calculated according to the accumulation of radon concentration curve in the accumulation chamber surface of the building material radon emanation coefficient. The full account of the decay of radon in building materials and pre-filled by measuring the radon concentration values ??at each time point measuring device deduced measuring device leakage rate, and improve the accuracy of the measurement. Due to the long accumulation of measurement exist \

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