An inversion decomposition method for better energy resolution of NaI(Tl)scintillation detectors based on a Gaussian response matrix

NaI(T1) scintillation detectors have been widely applied for gamma-ray spectrum measurements owing to advantages such as high detection efficiency and low price.However,the mitigation of the limited energy resolution of these detectors,which detracts from an accurate analysis of the instrument spectra obtained,remains a crucial need.Based on the physical properties and spectrum formation processes of NaI(T1) scintillation detectors,the detector response to gamma photons with different energies is represented by photopeaks that are approximately Gaussian in shape with unique full-width-at-half-maximum(FWHM) values.The FWHM is established as a detector parameter based on resolution calibrations and is used in the construction of a general Gaussian response matrix,which is employed for the inverse decomposition of gamma spectra obtained from the detector.The Gold and Boosted Gold iterative algorithms are employed to accelerate the decomposition of the measured spectrum.Tests of the inverse decomposition method on multiple simulated overlapping peaks and on experimentally obtained U and Th radionuclide series spectra verify the practicability of the method,particularly in the low-energy region of the spectrum,providing for the accurate qualitative and quantitative analysis of radionuclides.

Comparison of the simulated gamma-ray attenuation coefficients with the real measurements

The gamma-ray linear and the mass attenuation coefficients of Pb, Al, Cu, and plexiglass materials were calculated from both experimental and theoretical(simulation) methods. For the experimental results, a spectrometer, which was consisted of a Na I(Tl) inorganic scintillation detector, was used. The theoretical attenuation values were calculated by means of the FLUKA Monte Carlo(MC) and XCOM programs. Obtained attenuation coefficients from the experiment and the theoretical methods were compared with each other and literature values.

宁德核电厂在线啜吸装置检测破损燃料组件

介绍了宁德核电厂在线啜吸装置的优化及使用情况。对宁德核电在线啜吸装置的关键参数(高压、阈值、道宽)进行优化或重新设置、用图表形式对"阈值-计数率"数据进行分析、使用241Am放射源辅助判断81 ke V峰,使设备状态达到最佳,并成功用于核电站换料大修过程中破损燃料组件挑选的工作。