Statistical treatment of nuclear counting results

Abstract

Since the exact time a specific nucleus undergoes radioactive decay cannot be specified, nor can showers caused by secondary cosmic rays be predicted, statistical laws play an important role in almost all cases of experimental nuclear physics. This paper describes the method for the statistical treatment of nuclear counting results obtained experimentally by taking into account random variables pertaining to both frequent and infrequent phenomena. When processing counting measurement data, it is recommended to first discard spurious random variables that spoil the statistics by using Chauvenet’s criterion, as well as to test if the results in the statistical sample follow a unique statistical distribution by using the Wilcoxon rank-sum test (U-test). The verification of the suggested statistical method was performed on counting statistics obtained both from the radioactive source Cs-137 and background radiation, expected to follow the normal distribution and the Poisson distribution, respectively. Results show that the application of the proposed statistical method excludes random fluctuations of the radioactive source or of the background radiation from the total statistical sample, as well as possible inadequacies in the experimental set-up and show an extremely effective agreement of the theoretical distribution of random variables with the corresponding experimentally obtained random variables

Comparative Study of Gamma Radiation Effects on Solar Cells, Photodiodes, and Phototransistors

“…The professional digital multimeter AMPROBE 33XR was used for the current measurement. Combined measurement uncertainty for all measurements was less than 1.2% [12][13][14][15][16]. Measurements of I-V characteristics have been performed for illumination levels of 10 W/m 2 (for phototransistors BPW40), 4.32 W/m 2 (for solar panels), and 0.45 W/m 2 (for phototransistor LTR4206 and all photodiodes: BP104, BPW41N, BPW34, and SFH203FA).…”

Damage Induced by Neutron Radiation on Output Characteristics of Solar Cells, Photodiodes, and Phototransistors

“…The professional digital multimeter Amprobe 33XR was used for the current measurement. Combined measurement uncertainty for all measurements was less than 1.2% [12][13][14][15]. Measurements of -characteristics have been performed for illumination levels of 10 W/m 2 (for phototransistors BPW40), 4.32 W/m 2 (for solar panels), and 0.45 W/m 2 (for phototransistors LTR4206 and all photodiodes, BP104, BPW41N, BPW34, and SFH203FA).…”

Verification of a VFT measuring method based on the kerr electro-optic effect

“…The aim of the first stage was to warrant repeatability of generated fast transients (FTs), in view of their stochastic nature. It consisted in the following: 1) recording an FT produced by the cable generator; 2) modifying generator's parameters in order to achieve a high level of similarity between the generated FT and the one calculated by an electromagnetic transient program (EMTP); and 3) generating 50 voltage pulses (in order to obtain statistical sample large enough for ttest application used in confidence estimates for the mean value [32][33][34]) for which the exact values of amplitude, duration, rise and fall times are calculated. A 5 minute recess was introduced between successive measurements.…”

“…The χ 2 and Kolmogorov-Smirnov tests were used for establishing whether random variables belonged to normal, Weibull, or logarithmic distributions. Distribution parameters were determined by the method of moments [32][33][34][35]. The second stage of the experiment was dedicated to examining and eliminating all possible influences of the laser beam on the tested oil, and, finally, on validating the accuracy of the measurement method based on computerized laser tomography.…”