Abstract
A new characterization of the detector response for the EJ301 liquid scintillator based nSpec system has been conducted at the Los Alamos Neutron Science Center. The new characterization was accomplished in two orders of magnitude less time and with better statistics than the previous characterization. The new and old characterization methods were compared by conducting both types of characterization on two detectors (one EJ301 and one EJ301D). The two methods show consistent results and compare well to results previously published in the literature; however, the results from the characterization of the original nSpec detector show discrepancies that have been identified as being caused by oxygen being absorbed into the detector due to a leak. The new characterized detector response shows improved spectrum unfolding performance than the previous characterization. The cross talk of the detector system was also characterized as a function of incident neutron energy and found to have a negligible impact on spectrum unfolding results. Alternative materials (EJ301D and stilbene) were also characterized in a first step towards an upgraded system. The different materials show little difference in unfolding performance, but the comparison is ongoing. A SiPM based stilbene detector was used to evaluate the use of SiPMs in a future system upgrade. The SiPM provides adequate performance, but the custom SiPM readout results in a much longer pulse width than PMT based systems. The measured light output of the SiPM based stilbene compares well with the results in literature. Future work will look at additional materials (deuterated stilbene and organic glass) and optimizing the SiPM readout to decrease the pulse width.
| Original language | English |
|---|---|
| Article number | 168039 |
| Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
| Volume | 1049 |
| DOIs | |
| State | Published - Apr 2023 |
Funding
This work was supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001 ). This work benefits from the LANSCE accelerator facility. The authors would like to thank the staff at LANSCE for their assistance in helping to facilitate a successful experimental campaign. In particular, the authors thank the flight path scientists, Hye Young Lee and Sean Kuvin, for their assistance during preparation for the experiments and for characterizing and modifying the neutron beam, as well as Bill Waganaar for his timely response to requests to adjust the beam line slits.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | 89233218CNA000001 |
| National Nuclear Security Administration | |
| Los Alamos National Laboratory |
Keywords
- Neutron
- Passive interrogation
- Scintillation
- Spectrometer
- Spectroscopy
- Unfolding