Fast-neutron imaging spectrometer based on liquid scintillator loaded capillaries

Abstract

A fast-neutron imaging detector based on micrometric glass capillaries loaded with high refractive index liquid scintillator has been developed Neutron energy spectrometry is based on event-by-event detection and reconstruction of neutron energy from the measurement of the knock-on proton track length and the amount of light produced in the track. In addition, the detector can provide fast-neutron imaging with position resolution of tens of microns. The detector principle of operation, simulations and experimental results obtained with a small detector prototype are described. We have demonstrated by simulation energy spectrum reconstruction for incident neutrons in the range of 4-20 MeV. The energy resolution in this energy range was 10-15%. Preliminary experimental results of detector spectroscopic capabilities are presented

Energy-resolved fast neutron resonance radiography at CSNS

“…The fiber liquid scintillator array has been demonstrated in previous experiments [19,14]. Similarly, in our design the liquid scintillator is poured into a narrow silicon capillary, as depicted in the inset in Fig.…”

“…The deficiency of current design is the limited number of probes and channels, which results in a large pitch value and a lowresolution imaging output. In another perspective, the poor resolution also represents a great potential for development, as demonstrated by previous experiments [14,19]. The spatial resolution is anticipated to be significantly improved in future by developments in the mass production of detectors and the parallelization of amplification channels.…”

“…But they demonstrate liquid scintillator has a good efficiency on event counting. An related FNRR experiment with tiny liquid capillary is reported by Vartsky team in 2012 [14]. The capillary device is 3 cm long with inner average diameter 11 µm and its triangular corners were excluded 13 from the filling.…”

“…Liquid scintillator used here is EJ-309, which servers as an alternate to EJ-301 for similar optical performance, but with low chemical toxicity and high flash point. The neutron detection efficiency was estimated as 10-20% in the conclusion paragraph in citation [14]. For the sake of conservatism, a detection efficiency of 10% is chosen for our calculation while details are omitted.…”

A novel fast-neutron detector concept for energy-selective imaging and imaging spectroscopy

“…One of the most interesting concepts of fast-neutron detectors for imaging spectroscopy, proposed in the last decades by several groups, are based on a fine-structured matrix of neutron converters (scintillator), such as plastic fibers (or capillary tubes) filled with liquid scintillator [2][3][4] or an organic luminescent matrix screen; 5 by recording the images of the ionization tracks of the recoil protons, the detector allows the energy and direction of the impinging neutron to be reconstructed. The photo-sensor can be either a CCD camera, with limited field of view, 2 or a complicated and expensive position-sensitive gaseous photomultiplier.…”