Discrimination of α and β/γ interactions in a TeO2 bolometer

Abstract

TeO 2 crystals have proven to be superb bolometers for the search of neutrinoless double beta decay in many respects. However, if used alone, they do not exhibit any feature that allows to discriminate an α energy deposit from a β/γ one. This fact limits their ability to reject the background due to natural radioactivity and eventually affects the sensitivity of the search. In this paper we show the results of a TeO 2 crystal where, in coincidence with its bolometric heat signal, also the luminescence light escaping the crystal is recorded. The results show that we are able to measure the light produced by β/γ particles, which can be explained as due to Cerenkov emission. No light is detected from α particles, allowing the rejection of this background source.

High sensitivity phonon-mediated kinetic inductance detector with combined amplitude and phase read-out

“…1 The ideal light detector should provide excellent energy resolution (<20 eV), wide active surface (5 Â 5 cm 2 ), reliable and reproducible behavior, and the possibility of operating hundreds/thousands of channels. None of the existing technologies [2][3][4][5][6][7] is ready to fulfill all these requirements without further R&D. Since most of the proposed detectors are limited by the number of channels that can be easily installed and operated, the CALDER project 8 aims to develop a light detector starting from devices that are naturally multiplexed, such as the Kinetic Inductance Detectors (KIDs). 9 Thanks to the high sensitivity and to the multiplexed read-out, KIDs have been proposed in several physics sectors, such as photon detection, astronomy, [9][10][11] search for dark matter interactions, 12,13 and for the read-out of transition-edge sensors arrays.…”

“…The chip was mounted in a copper holder using Teflon supports with total contact area of about 3 mm 2 , and connected to SMA read-out by ultrasonic wire bonding. The detector was anchored to the coldest point of a 3 He/ 4 He dilution refrigerator with base temperature of 10 mK. The output signal was fed into a CITLF4 SiGe cryogenic low noise amplifier 23 with T N $ 7 K. Details about the room-temperature electronics and acquisition can be found in Refs.…”

CUORE-0 results and prospects for the CUORE experiment

“…Actually Cherenkov light emission in TeO 2 (which does not scintillate) has been detected using a secondary light detector [37] but more efficient light collection schemes and light detectors with lower threshold and better energy resolution are needed. Future directions include new thermal sensors on the light detector, such as TES [38] and MKIDs [39], and Luke effect [40] enhanced bolometers.…”

Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

“…To this end, additional detection channels are needed, since the absorber does not respond differently for energy releases of different particle types. To distinguish signal electrons from α background, light emission can be used, either from Cherenkov radiation [22,23] or scintillation light [24,25,28,29], where the auxiliary light detector is usually another bolometer facing the main one. Recently new studies on scintillating bolometers showed the possibility to distinguish α from β/γ particles without light readout thanks to a different time-dependent shape of the heat signal [30,31].…”