Lithium indium diselenide: A new scintillator for neutron imaging

Journal Article · Fri May 20 00:00:00 EDT 2016 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI:https://doi.org/10.1016/j.nima.2016.05.063· OSTI ID:1347560

Lukosi, Eric ^[1]; Herrera, Elan ^[1]; Hamm, Daniel ^[1]; Lee, Kyung -Min ^[1]; Wiggins, Brenden ^[2]; Trtik, Pavel ^[3]; Penumadu, Dayakar ^[1]; Young, Stephen ^[1]; Santodonato, Louis ^[4]; Bilheux, Hassina ^[4]; Burger, Arnold ^[5]; Matei, Liviu ^[5]; Stowe, Ashley C. ^[6]

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1. Univ. of Tennessee, Knoxville, TN (United States)
2. Y-12 National Security Complex, Oak Ridge, TN (United States)
3. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
5. Fisk Univ., Nashville, TN (United States)
6. Univ. of Tennessee, Knoxville, TN (United States); Y-12 National Security Complex, Oak Ridge, TN (United States)

Lithium indium diselenide, ⁶LiInSe₂ or LISe, is a newly developed neutron detection material that shows both semiconducting and scintillating properties. The 24% atomic density of ⁶Li yields a thermal neutron mean free path of only 920 μm. This paper reports on the performance of LISe crystals in scintillation mode for its potential use as a converter screen for thermal/cold neutron imaging. The spatial resolution of LISe, determined using a 10% value of the Modulation Transfer Function (MTF), was found to not scale linearly with thickness. Crystals having a thickness of 450 μm or larger resulted in an average spatial resolution of 67 μm, and the thinner crystals exhibited an increase in spatial resolution down to the Nyquist frequency of the CCD. The highest measured spatial resolution of 198 μm thick LISe (27 μm) outperforms a commercial 50 μm thick ZnS(Cu):⁶LiF scintillation screen (100 μm) by more than a factor of three. For the thicknesses considered in this study, it has been found that the light yield of LISe did not scale with its thickness, suggesting the need for optimizing the synthesis to enhance the scintillation mechanism. Absorption measurements indicate that the ⁶Li concentration is uniform throughout the samples and its absorption efficiency as a function of thickness follows general nuclear theory, indicating that the variation in apparent brightness is likely due to a combination of particle escape, light transport, and activation of the scintillation mechanisms. As a result, the presence of ¹¹⁵In and its long-lived ¹¹⁶In activation product did not result in ghosting (memory of past neutron exposure), demonstrating potential for using LISe for imaging transient systems.

• Research Organization: Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Contributing Organization: DOE Nuclear Energy University Programs Graduate Fellowship; DOE Scientific User Facilities Division, Office of Basic Energy Sciences
• Grant/Contract Number: NA0001942; NE0000094
• OSTI ID: 1347560
• Alternate ID(s): OSTI ID: 1425700
• Report Number(s): MS/STO-170116
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 830, Issue C; ISSN 0168-9002
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
neutron imaging
neutron detection
scintillator
lithium indium diselenide
LISe
thermal and cold neutrons