Conceptual design of the BRIKEN detector: A hybrid neutron-gamma detection system for nuclear physics at the RIB facility of RIKEN

Abstract

BRIKEN is a complex detection system to be installed at the RIB-facility of the RIKEN Nishina Center. It is aimed at the detection of heavy-ion implants, $\beta$-particles, $\gamma$-rays and $\beta$-delayed neutrons. The whole detection setup involves the Advanced Implantation Detection Array (AIDA), two HPGe Clover detectors and a large set of 166 counters of 3He embedded in a high-density polyethylene matrix. This article reports on a novel methodology developed for the conceptual design and optimisation of the 3He-tubes array, aiming at the best possible performance in terms of neutron detection. The algorithm is based on a geometric representation of two selected parameters of merit, namely, average neutron detection efficiency and efficiency flatness, as a function of a reduced number of geometric variables. The response of the detection system itself, for each configuration, is obtained from a systematic MC-simulation implemented realistically in Geant4. This approach has been found to be particularly useful. On the one hand, due to the different types and large number of 3He-tubes involved and, on the other hand, due to the additional constraints introduced by the ancillary detectors for charged particles and gamma-rays. Empowered by the robustness of the algorithm, we have been able to design a versatile detection system, which can be easily re-arranged into a compact mode in order to maximize the neutron detection performance, at the cost of the gamma-ray sensitivity. In summary, we have designed a system which shows, for neutron energies up to 1(5) MeV, a rather flat and high average efficiency of 68.6%(64%) and 75.7%(71%) for the hybrid and compact modes, respectively. The performance of the BRIKEN system has been also quantified realistically by means of MC-simulations made with different neutron energy distributions.

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Cited by in corpus (10)

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• Commissioning of the BRIKEN detector for the measurement of very exotic beta-delayed neutron emitters
• Segmented YSO scintillation detectors as a new $\beta$-implant detection tool for decay spectroscopy in fragmentation facilities
• Neutron flux and spectrum in the Dresden Felsenkeller underground facility studied by moderated ${}^3$He counters
• Nuclear Weak Rates and Nuclear Weak Processes in Stars
• Beta-decay properties of neutron-rich Ca, Ti, and Cr isotopes
• The ORNL Analysis Technique for Extracting $\beta$-Delayed Multi-Neutron Branching Ratios with BRIKEN
• The ${}^3$He BF${}_3$ Giant Barrel (HeBGB) Neutron Detector
• Concept of a fast neutron detector based on 10B-RPCs
• miniBELEN: a modular neutron counter for (alpha,n) reactions