COuntLOss in NEutron multiplicity assessment (COLONEMA)

Abstract

An approach has been developed to model in a simple way count loss in Passive Neutron Coincidence and Multiplicity Counting (PNCMC) systems in order to determine dead time corrections. The approach does not require to simulate the full PNCMC system, but rather uses basic information from the PNCMC system such as the neutron detection efficiency, the counters cabling scheme and the dead times of different electronic components of the system. A good agreement is found between the measured dead time parameters of a neutron multiplicity counter described in the literature and the dead time parameters calculated using the presented approach. Program summaryProgram title: COLONEMACatalogue identifier: AEYS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEYS_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 2900No. of bytes in distributed program, including test data, etc.: 18753Distribution format: tar.gzProgramming language: C++.Computer: Unix/Linux workstations and PC.Operating system: Unix, Linux and windows, provided a C++ compiler has been installed. Examples were tested under Debian Linux.RAM: Depends on the simulated neutron source strength and detector efficiency. !at most, the example presented in the article allocates about 2 GB of virtual memory.Classification: 11.7, 17.7.Nature of problem: To determine the mass of fissile materials inside an unknown object, a passive neutron multiplicity or coincidence counting is performed in which single, double and triple neutron rates are measured. The measured rates must however be corrected from count losses due to dead time when the count rate is large.Solution method: Unlike approaches based on time consuming Monte Carlo transportation of the neutrons in the inspection system combined with treatment that take into account count losses due to dead time, a versatile Monte Carlo approach is presented which uses only the detection efficiency of the system and the dead time of the electronics and counters.Running time: It takes about 109 min on an Intel Xeon X5550 2.676 GHz processor to run the example presented.