Contribution Poster (WITHDRAWN)
NaI-based scintillating calorimeter – a new approach for dark matter search
Although nowadays many astrophysical observations give evidence for the existence of dark matter and we know that its concentration is five times more than baryonic matter in the Universe, its nature still remains unknown. Clarifying the nature and origin of dark matter is one of the big challenges for modern particle physics. Dark matter direct detection experiments aim to register the elusive signals in the detector induced by the interacting particles. The possible detection channels induced by such scattering processes, depending on the detector material, can be scintillation light, charge and phonon (heat). Since many years the DAMA/LIBRA experiment, utilizing only one detection channel of the NaI(Tl) scintillators (scintillation light) observes an annual modulation signal, which is in agreement with the one expected from dark matter particles. However, the positive evidence of the DAMA/LIBRA experiment is in contradiction with the null results of most of the other dark matter direct detection experiments. The R&D project COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) aims to develop a cryogenic scintillating calorimeter using an undoped NaI-crystal as a target. Using the same target material as DAMA group, this experimental approach offers the unique possibility to investigate and clarify the above mentioned experimental discrepancy. Dark matter particles interacting with the NaI detector material generate a phonon signal and scintillation light. The energy of the interacting particle is determined based on the phonon signal. The simultaneously measured scintillation light serves to identify the nature of the interacting particle, providing a powerful tool to discriminate dark matter signals from background. We will report the first results obtained using NaI (undoped) crystal as a cryogenic scintillating calorimeter prototype, focusing on the detector performance such as energy threshold, energy resolution and particle discrimination. The perspectives of the COSINUS project will be also discussed.