Measurements and simulations to investigate the feasibility of neutron multiplicity counting in the current mode of fission chambers
Paper i proceeding, 2020

In two earlier papers [1], [2] we investigated the possibility of extracting traditional multiplicity count rates from the cumulants of fission chamber signals in current mode. It was shown that if all neutrons emitted from the sample simultaneously are also detected simultaneously, the multiplicity rates can be retrieved from the first three cumulants of the currents of up to three detectors, but the method breaks down if the detections of neutrons of common origin take place with a time delay spread wider than the pulse shape. To remedy these shortcomings, in this work we extended the theory to two- and three-point distributions (correlations). It was found thatthe integrals of suitably chosen two- and three-point moments with respect to the time differences become independent of the probability density of the time delays of detections. With this procedure, the multiplicity rates can be retrieved from the detector currents for arbitrary time delay distributions. To demonstrate the practical applicability of the proposed method, a measurement setup was designed and built. The statistics (shape and amplitude distribution) of the detector pulse were investigated as important parameters of the theoretical model. Simulations were performed to estimate the expected value of the multiplicity rates in the built setup. Measurements were performed and two types of moments (the mean and the covariance function) of the recorded detector signals were calculated. Values of singles rates were successfully recovered.

fission chamber

nuclear safeguards

multiplicity counting


Lajos Nagy

Budapesti Muszaki es Gazdasagtudomanyi Egyetem

Imre Pazsit

Chalmers, Fysik, Subatomär, högenergi- och plasmafysik

Lénárd Pál

Magyar Tudomanyos Akademia

Gergely Klujber

Budapesti Muszaki es Gazdasagtudomanyi Egyetem

Mate Szieberth

Budapesti Muszaki es Gazdasagtudomanyi Egyetem

EPJ Web of Conferences

21016275 (ISSN) 2100014X (eISSN)

Vol. 225 07011
978-2-7598-9093-4 (ISBN)

International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications
Portoroz, Slovenia,


Astronomi, astrofysik och kosmologi

Annan kemi

Strömningsmekanik och akustik



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