A CaMoO₄Crystal Low Temperature Detector for the AMoRE Neutrinoless Double Beta Decay Search

Abstract

We report the development of a CaMoO4 crystal low temperature detector for the AMoRE neutrinoless double beta decay (0νββ) search experiment. The prototype detector cell was composed of a 216 g CaMoO4 crystal and a metallic magnetic calorimeter. An over-ground measurement demonstrated FWHM resolution of 6-11 keV for full absorption gamma peaks. Pulse shape discrimination was clearly demonstrated in the phonon signals, and 7.6 σ of discrimination power was found for the α and β/γ separation. The phonon signals showed rise-times of about 1 ms. It is expected that the relatively fast rise-time will increase the rejection efficiency of two-neutrino double beta decay pile-up events which can be one of the major background sources in 0νββ searches.

Neutron and muon-induced background studies for the AMoRE double-beta decay experiment

“…The simulation results with configuration 1 for the single-hit event rate in the (2)(3)(4)(5)(6)(7)(8) MeV energy region at the six energy binnings are shown in red in Fig 9. It shows the single-hit background rates in the level of 10 −3 counts/(keV·kg·yr) for the overall energy range.…”

“…The AMoRE-II experiment will use a ∼200 kg array of molybdate crystals with the aim of achieving the zerobackground level of <10 −5 counts/(keV·kg·yr) (ckky) in the region of interest (ROI), 3.034±0.010 MeV. The ROI is given by the Q value of 0νββ of 100 Mo in molybdate crystals, which is at 3034.40 (17) keV [3], and the energy range based on the energy resolution of the detector [4].…”

Cryogenic detectors for dark matter search and neutrinoless double beta decay

“…Furthermore, detectors for applications in the search for the neutrinoless double beta decay with scintillating crystals (e.g., AMoRE [13] and LUMINEU [14]) are also under development. Fig.…”

“…A prominent candidate is the isotope 100 Mo that can be enriched in molybdate crystals as, e.g., ZnMoO 4 as used in the LUMINEU experiment [43], CaMoO 4 crystals as operated in the AMoRE experiment [13] or Li 2 MoO 4 crystals [44]. As all these crystals are scintillating, the phonon-light technique can be applied for the suppression of α background.…”

Li2MoO4 Crystals Grown by Low-Thermal-Gradient Czochralski Technique

“…The AMoRE collaboration utilizes calcium molybdate (CaMoO 4 ) crystal scintillators [15,16] [23]. Moreover, Li 2 MoO 4 based detectors can be also used for neutron counting in low background conditions [22] and search for solar axions [24].…”