Design, Construction and Characterization of a Portable Fast-Neutron Detector

Description

At European Spallation Source ERIC, 2 GeV proton bunches will be accelerated towards a tungsten target where spallation will occur, producing a wide neutron energy spectrum. Despite the shielding and moderators in place to stop and/or reduce their energy, a significant portion of the most energetic neutrons, called prompt neutrons, might still reach the sample position of a neutron-scattering instrument. It has been previously shown that these prompt neutrons contribute to a degradation of the signal-to-noise ratio of the detectors. Clearly, a tool for identifying sources of fast-neutron background would be very valuable. The design goals of the envisioned Portable Fast-Neutron Diagnostic Detector include portability, durability, fast response and the ability for performing self-triggering time-of-flight measurements complete with tracking to localize fast-neutron sources. Within the context of this thesis, the detector system was conceptualized, designed and a prototype assembled. Testing was carried out with a plutonium/beryllium source and a industry-standard liquid scintillator detector to define a tagged fast-neutron beam (2.8-6.3 MeV). It was shown that the neutron response is energy dependent and improves at lower energies. Fast-neutron tracking capabilities of the detector were demonstrated.

Period	2017
Examinee/Supervised person	Nicholai Mauritzson
Examination/Supervision held at
Degree of Recognition	National