SELECTIVE ANALYS OF THE WORK OF 5-BALL BONNER SPECTROMETER

Abstract

The data obtained during the test of the generated Bonner neutron spectrometer of an activation type consisting of 5 polyethylene balls are analyzed. Indium was used as the activated material. Measurements were made an electron beam with energy E=12 MeV was transformed into a 100-micron tantalum (e,γ)-converter into γ-radiation, which fell on the lead plumbum (γ,n)-converter. The neutrons from converter were incident on the spectrometer balls. Different parts of the neutrons arrived in each of them, and therefore the activation of indium tablets was different. After irradiation on the accelerator, indium tablets were extracted from the balls, and was placed in a γ spectrometer, where the degree of activation of the tablet was determined. Thus, the results of the measurements were 5 numbers characterizing the activation of 5-ball tablets. Assuming some function F(E,aj), which can describe the neutron spectrum and depends on several parameters aj, and, by having the response function of the ith ball φi(E), activation can be represented as a convolution of functions F(E,aj) and φi(E). The results of mathematical processing of measurement data of radioactivity induced in Indium are presented. Model based on minimization of the quality functional and nonlinear regression equations is constructed. Using the stochastic recurrent algorithm, the problem of neutron spectrum restoration is solved. For the used four-parameter model of the spectrum, such as the Maxwell distribution, estimates of its parameters are obtained, as well as estimates of the errors of parameter estimates.