Evaluation of CLYC-6 and CLYC-7 scintillators for detection of nuclear materials

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2021-10, Vol.1012, p.165622, Article 165622
• Main Authors: Pérez-Loureiro, David, Kamaev, Oleg, Bentoumi, Ghaouti, Li, Liqian, Jewett, Cybele, Thompson, Martin
• Format: Article
• Language: English
• Subjects: CLYC scintillator; Gamma-ray spectroscopy; Neutron detection; Nuclear material detection; Nuclear security; Pulse shape discrimination
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2021.165622

The Cs2LiYCl6 (CLYC) scintillator is proven to be suitable for dual γ-ray/neutron detection owing to its distinct response to both radiation types. This feature makes this material attractive for applications in nuclear security and safeguards. Two 3.8 cm diameter CLYC crystals, one enriched with 95% 6Li, and the second one depleted of 6Li and with >99% 7Li, were characterized with conventional gamma-ray sources as well as with (α, n) and a bare and heavy-water-moderated 252Cf neutron source. The suitability of the two scintillators for detection and characterization of special fissionable materials was evaluated experimentally using uranium and plutonium samples with different isotopic concentrations. Whereas the two detectors have comparable performances for gamma rays, 6Li-enriched CLYC shows better response for neutron gross count, because of its sensitivity to thermal neutrons. A simple method based on neutron/gamma ratios within certain energy regions has been demonstrated to be able to distinguish between different neutron emitting sources, showing very promising results for the development of more sophisticated identification algorithms based on neutron/gamma signatures. The results reported here suggest the 6Li-enriched one as a better candidate for nuclear security applications.