Comparative scintillation performance of EJ-309, EJ-276, and a novel organic glass

Abstract

A : An organic glass scintillator developed by Sandia National Laboratories was characterized in terms of its light output and pulse shape discrimination (PSD) properties and compared to commercial liquid (EJ-309) and plastic (EJ-276) organic scintillators. The electron light output was determined through relative comparison of the 137 Cs Compton edge location. The proton light yield was measured using a double time-of-flight technique at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. Using a tunable broad-spectrum neutron source and an array of pulse-shape-discriminating observation scintillators, a continuous measurement of the proton light yield was performed for EJ-309 (200 keV−3.2 MeV), EJ-276 (170 keV−4.9 MeV), and the organic glass (50 keV−20 MeV). Finally, the PSD properties of the organic glass, EJ-309, and EJ-276 were evaluated using an AmBe source and compared via a figure-of-merit metric. The organic glass exhibited a higher electron light output than both EJ-309 and EJ-276. Its proton light yield and PSD performance were comparable to EJ-309 and superior to that of EJ-276. With these performance characteristics, the organic glass scintillator is well poised to replace current state-of-the-art PSD-capable scintillators in a range of fast neutron detection applications.

Simultaneous measurement of organic scintillator response to carbon and proton recoils

“…Figure 7 displays the measured EJ-309 proton and carbon light yield relations alongside previous works. The EJ-309 proton light yield is compared to a double TOF measurement from Laplace et al [30], and the results are consistent within the estimated uncertainties. The EJ-309 carbon light yield data are compared to a measurement from Norsworthy et al [49], which used a mono-energetic neutron source and an indirect technique to provide the carbon light yield relation in electronequivalent light units.…”

“…That is, the EJ-309 carbon light yield relative to the light produced by a 477 keV electron is lower than that of EJ-204 by approximately 55% and 33% at 2 MeV and 4 MeV, respectively. This is in contrast to the behavior observed for the relative proton light yield relations of these materials for proton energies of 2 to 4 MeV, where literature measurements demonstrate a relative proton light yield of EJ-309 greater than that of EJ-204 [28,30,45]. In this energy range, excitation densities are over an order of magnitude greater for carbon recoils compared to protons.…”

“…The consistency of the measured EJ-309 proton and carbon light yield relations with literature measurements lends confidence both to the extension of the double TOF technique and its application towards the generation of novel carbon light yield data. The red open symbols represent previous EJ-309 proton (Laplace 2020: [30]) and carbon (Norsworthy 2018: [49]) light yield measurements. The error bars on the abscissa represent a bin width and those on the ordinate axis include both the statistical and systematic uncertainties.…”

“…To facilitate comparison against previous EJ-309 and EJ-204 proton light yield measurements in which the light output calibration was performed using a 137 Cs source [30,45], the light unit was defined such that the light output corresponding to the Compton edge of a 662 keV γ ray was set to 1. This is in contrast to an electron-equivalent light unit, commonly employed to describe scintillator light output, which implicitly assumes the proportionality of the scintillator response to electron recoils.…”

“…In this work, the proton and carbon light yield of the EJ-309 and EJ-204 organic scintillators were measured simultaneously over a range of recoil energies. The EJ-309 liquid scintillator has pulse shape discrimination (PSD) properties [19] and was selected as a standard of reference given the relatively large body of work characterizing the proton light yield of this medium [20][21][22][23][24][25][26][27][28][29][30]. The EJ-204 plastic scintillator has a rapid temporal response and long attenuation length [31], and it has been identified as a prime candidate for use in cutting-edge compact neutron imaging systems [32].…”