中文摘要：

Effect factors of the absorption of the source, air,entrance window, and dead layer of a detector must be consideredin the measurement of monoenergetic alpha particles,along with statistical noise and other factors that collectivelycause the alpha spectrum to exhibit a well-known low-energytail. Therefore, the establishment of an alpha spectrumdetector response function from the perspective of a signalingsystem must consider the various factors mentioned above.The detector response function is the convolution of an alphaparticlepulse function, two exponential functions, and aGaussian function, followed by calculation of the parametersof the detector response function using the weighted leastsquaresfitting method as proposed in this paper. In ourexperiment, 239Pu alpha spectra were measured by a highresolution,passivated implanted planar silicon (PIPS) detector at 10 levels of vacuum and 10 source-detector distances.The spectrum-fitting results were excellent as evaluatedby reduced Chi-square (v2) and correlation coefficients.Finally, the variation of parameters with vacuum level andsource-detector distance was studied. Results demonstratethat r, s1, and s2 exhibit no obvious trend of variation withvacuum in the range 2000-20,000 mTorr, and at a confidencelevel of 95%, the values of s1 and s2 decline in a similarfashion with source-detector distance by the power exponentialfunction, while the value of r declines linearly.

英文摘要：

Effect factors of the absorption of the source, air, entrance window, and dead layer of a detector must be considered in the measurement of monoenergetic alpha particles, along with statistical noise and other factors that collectively cause the alpha spectrum to exhibit a well-known low-energy tail. Therefore, the establishment of an alpha spectrum detector response function from the perspective of a signaling system must consider the various factors mentioned above. The detector response function is the convolution of an alpha-particle pulse function, two exponential functions, and a Gaussian function, followed by calculation of the parameters of the detector response function using the weighted least-squares fitting method as proposed in this paper. In our experiment, ²³⁹Pu alpha spectra were measured by a high-resolution, passivated implanted planar silicon (PIPS) detector at 10 levels of vacuum and 10 source-detector distances. The spectrum-fitting results were excellent as evaluated by reduced Chi-square (χ ²) and correlation coefficients. Finally, the variation of parameters with vacuum level and source-detector distance was studied. Results demonstrate that σ, τ₁, and τ₂ exhibit no obvious trend of variation with vacuum in the range 2000-20,000?mTorr, and at a confidence level of 95%, the values of τ₁ and τ₂ decline in a similar fashion with source-detector distance by the power exponential function, while the value of σ declines linearly.