Characterization of a neutron–beta counting system with beta-delayed neutron emitters

• DOI: 10.1016/j.nima.2015.10.082
• Publication Date: 2015-11-03T20:36:09Z
• Authors: J. Agramunt; J.L. Tain; M.B. Gómez-Hornillos; A.R. Garcia; F. Albiol; A. Algora; R. Caballero-Folch; F. Calviño; D. Cano-Ott; G. Cortés; C. Domingo-Pardo; T. Eronen; W. Gelletly; D. Gorelov; V. Gorlychev; H. Hakala; A. Jokinen; M.D. Jordan; A. Kankainen; V. Kolhinen; L. Kucuk; T. Martinez; P.J.R. Mason; I. Moore; H. Penttilä; Zs. Podolyák; C. Pretel; M. Reponen; A. Riego; J. Rissanen; B. Rubio; A. Saastamoinen; A. Tarifeño-Saldivia; E. Valencia
• Keywords: Neutron Detection; Bonner sphere

A new detection system for the measurement of beta-delayed neutron emission probabilities has been characterized using fission products with well known ß-delayed neutron emission properties. The setup consists of BELEN-20, a 4p neutron counter with twenty 3He proportional tubes arranged inside a large polyethylene neutron moderator, a thin Si detector for ß counting and a self-triggering digital data acquisition system. The use of delayed-neutron precursors with different neutron emission windows allowed the study of the effect of energy dependency on neutron, ß and ß-neutron rates. The observed effect is well reproduced by Monte Carlo simulations. The impact of this dependency on the accuracy of neutron emission probabilities is discussed. A new accurate value of the neutron emission probability for the important delayed-neutron precursor 137I was obtained, Pn=7.76(14)%.