Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches

Abstract

Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO 4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreement.

Low background techniques in bolometers for double-beta decay search

“…63,87,[186][187][188][189] Consequently, the light collection efficiency is crucial for detectors with low light yield, thus the study of light production and transport, as e.g., 190 are rather important for the detector optimization. In particular, the light collection can be enhanced by improving the material quality (transmittance to the emitted light), by choosing a proper crystal shape and surface treatment, 102,191,192 by reducing the light reflection in the photodetector, [193][194][195] by adding an efficient reflector, 41,63 as well as by using an optical bolometer with an area comparable to a crystal-side surface. 41, 63…”

Dielectric and magnetic characteristics of Ca1−xMnxMoO4 (0 ≤ x ≤ 0.15) nanomaterials

“…Metal molybdates form a wide and important class of inorganic materials that have a high application potential in various fields such as scintillator detectors, phosphors and electro-optic applications (Zhang et al 2015; Bavykina et al 2009; Zhou et al 2011; Danevich et al 2014; Belogurov et al 2005; Mikhailik et al 2007; Korzhik et al 2008; Lei and Yan 2008; Shivakumara et al 2015). Divalent metal molybdates with relatively large cations such as Ca 2+ , Sr 2+ , Ba 2+ and Pb 2+ (ionic radius above 99 pm) exist in scheelite-type structure (tetragonal symmetry, space group I4 1 /a ; Z  = 4) where molybdenum ions adopt tetrahedral coordination, while divalent metal ions represent an eight-coordinated position (Sczancoski et al 2008; Sczancoski et al 2009; Ghosh et al 2015).…”

Cryogenic phonon–scintillation detectors with PMT readout for rare event search experiments

“…The input parameters for the simulations were taken from ref. [46]. The results of modelling indicated that reducing the distance between scintillator and PMT as well as moving the back reflector close to the crystal increases the efficiency of photon detection (see Fig.…”