Shift-register coincidence electronics system for thermal neutron counters

Abstract

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On the Mathematical Calibration of the Active Well Neutron Coincidence Counter (AWCC)

“…ν T is the total neutron multiplicity for the mean value of neutrons emitted per spontaneous or induced fission (it could be deduced from induced fission multiplicity table from the MCNPX output file for every correspondence single or couple measured samples). 4 n/s to activate thermal fission in assayed samples. The yield was calculated from the initial certified yield and depending on the data given by Tagziria and Looman (2012) [24].…”

“…Real coincidence count rates (C r5 ) for four of the SNM samples (SRM969-071, 194, 295 and 446) measured as single samples covering a small range of 235 U masses (from 1.2 g to 7.5 g, Table (4). The outer shell of the empty unsealed aluminum can was used as a holder for these singles samples from the bottom of the detector.…”

“…The results obtained from the model (real coincidence count rates, C r5 ) were compared with measurements to check the accuracy of the model. Tables (4) and (5) give the obtained results for the measured and modeled coincidence count rates, for single and coupled NM samples, respectively.…”

“…The active mode operation of the AWCC is based on the detection of coincidence neutrons produced from induced fission of 235 U isotope using interrogation neutron sources (one or more Am-Li neutron sources are inserted in the top and/or bottom of the detector well). The AWCC construction and operation was described and explained by different authors in many papers and technical reports [1][2][3][4][5].…”

A proposed semi-empirical method for 235U mass calibration of the active-well neutron coincidence counter

“…A cadmium sleeve on the outside of the detector reduces the background rate from low-energy neutrons in the room. A pulse processing circuit (shift register) keeps track of real and total (real+acci-dental) coincidence neutrons [7][8][9][10].…”