CRESST is one of the most prominent direct detection experiments for dark matter particles with sub-GeV/c ^2 mass. One of the advantages of the CRESST experiment is the possibility to include a large variety of nuclides in the target material used to probe dark matter interactions. In this work, we discuss in particular the interactions of dark matter particles with protons and neutrons of ^6 Li. This is now possible thanks to new calculations on nuclear matrix elements of this specific isotope of Li. To show the potential of using this particular nuclide for probing dark matter interactions, we used the data collected previously by a CRESST prototype based on LiAlO _2 and operated in an above ground test-facility at Max-Planck-Institut für Physik in Munich, Germany. In particular, the inclusion of ^6 Li in the limit calculation drastically improves the result obtained for spin-dependent interactions with neutrons in the whole mass range. The improvement is significant, greater than two order of magnitude for dark matter masses below 1 GeV/c ^2 , compared to the limit previously published with the same data.

In this work we report the realization of the first low-threshold cryogenic detector that uses diamond as absorber for astroparticle physics applications. We tested two 0.175 g CVD diamond samples, each instrumented with a W-TES. The sensors showed transitions at about 25 mK. We present the performance of the diamond detectors and we highlight the best performing one, where we obtained an energy threshold as low as 16.8 eV. This promising result lays the foundation for the use of diamond for different fields of applications where low threshold and excellent energy resolution are required, as i.e. light dark matter searches and BSM physics with coherent elastic neutrino nucleus scattering.

A newly developed experimental technique based on 169 Tm-containing cryogenic bolometer detector was employed in order to perform the search for solar axions. The inclusion of target material into the active detector volume allowed for significant increase in sensitivity to axion parameters. A short 6.6 days measurement campaign with 8.18 g detector crystal yielded the following limits on axion couplings: | g A γ ( g A N 0 + g A N 3 ) ≤ 1.44 × 10 − 14 GeV − 1 and | g A e ( g A N 0 + g A N 3 ) ≤ 2.81 × 10 − 16 . The achieved results demonstrate high scalability potential of presented experimental approach.

In the current direct dark matter search landscape, the leading experiments in the sub-GeV mass region mostly rely on cryogenic techniques which employ crystalline targets. One attractive type of crystals for these experiments is those containing lithium, due to the fact that ^7Li is an ideal candidate to study spin-dependent dark matter interactions in the low mass region. Furthermore, ^6Li can absorb neutrons, a challenging background for dark matter experiments, through a distinctive signature which allows the monitoring of the neutron flux directly on site. In this work, we show the results obtained with three different detectors based on LiAlO_2 , a target crystal never used before in cryogenic experiments.

To cope with the foreseen demand for tungsten-based TESs in the current and future phases of the CRESST experiment, we investigated the possibility to implement a reliable, simple and reproducible fabrication method using sputtering. In this contribution, we present the method under development for tungsten deposition using conventional magnetron sputtering with xenon as sputtering gas. TESs with transition temperatures ( T_c ) down to 15 mK have been obtained with transition widths smaller than 1 mK. We also give a first assessment on the reproducibility of the process and present the potential for tuning of the T_c .

The CRESST-III experiment searches for direct interactions of dark matter with ordinary matter. The main event signature would be a nuclear recoil inside one of the scintillating CaWO4 crystals. Operating the crystals as cryogenic calorimeters provides a phonon signal as measure of the deposited energy. The simultaneous readout of both signals is used to actively discriminate backgrounds. CRESST-III focuses on the sub-GeV/c2 mass region where the sensitivity is driven by the threshold. In the first data taking campaign of CRESST-III from 2016-2018 an unprecedented low threshold of 30.1 eV for nuclear recoils was obtained. In this contribution, we will report the status of the experiment and the latest results.

Despite the multiple and convincing evidence of the existence of dark matter (DM) in our Universe, its detection is one of the most pressing questions in particle physics. As of today, there is no unambiguous hint which could clarify the particle nature of DM. For these reasons, a huge experimental effort is ongoing, trying to realize experiments which can probe the particle properties of DM. In particular, direct search experiments are trying to cover the largest possible mass range, from a few MeVs up to TeVs. Particularly suited for the sub-GeV mass region are detectors containing light nuclei, which are sensitive to the scattering of light DM candidates. Among them, we investigate a carbon-based absorber to explore DM masses down to the MeV region. Thanks to their cryogenic properties (high Debye temperature and long-lived phonon modes), carbon-based materials operated as low temperature calorimeters could reach an energy threshold in the eV range and would allow for the exploration of new parameters of the DM–nucleus cross section. Despite several proposals, the possibility of operating a carbon-based cryogenic detector is yet to be demonstrated. In this contribution, the preliminary results obtained with a diamond absorber operated with a TES temperature sensor will be reported. The potential of such a detector in the current landscape of DM searches will also be illustrated.

AbstractA search for resonant absorption of solar axions by $$^{169}\mathrm {Tm}$$169Tm nuclei was carried out. A newly developed approach involving low-background cryogenic bolometer based on $$\mathrm {Tm}_{3} \mathrm {Al}_{5} \mathrm {O}_{12}$$Tm3Al5O12 crystal was used that allowed for significant improvement of sensitivity in comparison with previous $$^{169}\mathrm {Tm}$$169Tm based experiments. The measurements performed with 8.18 g crystal during 6.6 days exposure yielded the following limits on axion couplings: $$|g_{A\gamma } (g_{AN}^0 + g_{AN}^3) \le 1.44 \times 10^{-14}\,{{\mathrm{GeV}}^{-1}}$$|gAγ(gAN0+gAN3)≤1.44×10-14GeV-1 and $$|g_{Ae} (g_{AN}^0 + g_{AN}^3) \le 2.81 \times 10^{-16}$$|gAe(gAN0+gAN3)≤2.81×10-16.

In this work, a first cryogenic characterization of a scintillating LiAlO_2 single crystal is presented. The results achieved show that this material holds great potential as a target for direct dark matter search experiments. Three different detector modules obtained from one crystal grown at the Leibniz-Institut für Kristallzüchtung (IKZ) have been tested to study different properties at cryogenic temperatures. Firstly, two 2.8 g twin crystals were used to build different detector modules which were operated in an above-ground laboratory at the Max Planck Institute for Physics (MPP) in Munich, Germany. The first detector module was used to study the scintillation properties of LiAlO_2 at cryogenic temperatures. The second achieved an energy threshold of ( 213.02± 1.48 ) eV which allows setting a competitive limit on the spin-dependent dark matter particle-proton scattering cross section for dark matter particle masses between 350 MeV/c^2 and 1.50 GeV/c^2 . Secondly, a detector module with a 373 g LiAlO_2 crystal as the main absorber was tested in an underground facility at the Laboratori Nazionali del Gran Sasso (LNGS): from this measurement it was possible to determine the radiopurity of the crystal and study the feasibility of using this material as a neutron flux monitor for low-background experiments.

The $^{169}$Tm nuclide has first nuclear level at 8.41 keV with magnetic type transition to the ground state and, therefore, can be used as a target nucleus for the search of resonant absorption of solar axions. We plan to use a Tm-containing crystal of a garnet family Tm$_3$Al$_5$O$_{12}$ as a bolometric detector in order to search for the excitation of the first nuclear level of $^{169}$Tm via the resonant absorption of solar axions. With this perspective in mind, a sample of the Tm$_3$Al$_5$O$_{12}$ crystal was grown and tested for its bolometric and optical properties. Measurements of chemical and/or radioactive contaminations were performed as well. In this paper we present the test results and estimate the requirements for a future low-background experimental setup.

Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) is a long-standing direct dark matter detection experiment with cryogenic detectors located at the underground facility Laboratori Nazionali del Gran Sasso in Italy. CRESST-III, the third generation of CRESST, was specifically designed to have a world-leading sensitivity for low-mass dark matter (DM) (less than 2 GeV/$$\hbox {c}^{2}$$) to probe the spin-independent DM-nucleus cross section. At present, a large part of the parameter space for spin-independent scattering off nuclei remains untested for dark matter particles with masses below few GeV/$$\hbox {c}^{2}$$ although many motivated theoretical models having been proposed. The CRESST-III experiment employs scintillating $$\hbox {CaWO}_{{4}}$$ crystals of $$\sim$$ 25 g as target material for dark matter interactions operated as cryogenic scintillating calorimeters at $$\sim$$ 10 mK. CRESST-III first data taking was successfully completed in 2018, achieving an unprecedented energy threshold for nuclear recoils. This result extended the present sensitivity to DM particles as light as $$\sim$$ 160 MeV/$$\hbox {c}^{2}$$. In this paper, an overview of the CRESST-III detectors and results will be presented.

CRESST is a direct dark matter search experiment, aiming for an observation of nuclear recoils induced by the interaction of dark matter particles with cryogenic scintillating calcium tungstate crystals. Instead of confining ourselves to standard spin-independent and spin-dependent searches, we re-analyze data from CRESST-II using a more general effective field theory (EFT) framework. On many of the EFT coupling constants, improved exclusion limits in the low-mass region (< 3–4 GeV/ $$c^2$$ ) are presented.

In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a $$\hbox {Li}_2\hbox {MoO}_4$$ target crystal in an above-ground laboratory. Despite the high background environment, the detector sets a competitive limit on spin-dependent interactions of dark matter particles with protons and neutrons for masses between $$0.8~\hbox {GeV/c}^2$$ and $$1.5~\hbox {GeV/c}^2$$ .

Abstract In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a $$\hbox {Li}_2\hbox {MoO}_4$$ Li2MoO4 target crystal in an above-ground laboratory. Despite the high background environment, the detector sets a competitive limit on spin-dependent interactions of dark matter particles with protons and neutrons for masses between $$0.8~\hbox {GeV/c}^2$$ 0.8GeV/c2 and $$1.5~\hbox {GeV/c}^2$$ 1.5GeV/c2 .

The CRESST experiment is a direct dark matter search which aims to measure interactions of potential dark matter particles in an earth-bound detector. With the current stage, CRESST-III, we focus on a low energy threshold for increased sensitivity towards light dark matter particles. In this manuscript we describe the analysis of one detector operated in the first run of CRESST-III (05/2016-02/2018) achieving a nuclear recoil threshold of 30.1eV. This result was obtained with a 23.6g CaWO$_4$ crystal operated as a cryogenic scintillating calorimeter in the CRESST setup at the Laboratori Nazionali del Gran Sasso (LNGS). Both the primary phonon/heat signal and the simultaneously emitted scintillation light, which is absorbed in a separate silicon-on-sapphire light absorber, are measured with highly sensitive transition edge sensors operated at ~15mK. The unique combination of these sensors with the light element oxygen present in our target yields sensitivity to dark matter particle masses as low as 160MeV/c$^2$.

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Building on the successful experience in operating the DarkSide-50 detector, the DarkSide Collaboration is going to construct DarkSide-20k, a direct WIMP search detector using a two-phase Liquid Argon Time Projection Chamber (LAr TPC) with an active (fiducial) mass of 23 t (20 t). This paper describes a preliminary design for the experiment, in which the DarkSide-20k LAr TPC is deployed within a shield/veto with a spherical Liquid Scintillator Veto (LSV) inside a cylindrical Water Cherenkov Veto (WCV). This preliminary design provides a baseline for the experiment to achieve its physics goals, while further development work will lead to the final optimization of the detector parameters and an eventual technical design. Operation of DarkSide-50 demonstrated a major reduction in the dominant 39Ar background when using argon extracted from an underground source, before applying pulse shape analysis. Data from DarkSide-50, in combination with MC simulation and analytical modeling, shows that a rejection factor for discrimination between electron and nuclear recoils of \(>3 \times 10^{9}\) is achievable. This, along with the use of the veto system and utilizing silicon photomultipliers in the LAr TPC, are the keys to unlocking the path to large LAr TPC detector masses, while maintaining an experiment in which less than \(< 0.1\) events (other than \(\nu\)-induced nuclear recoils) is expected to occur within the WIMP search region during the planned exposure. DarkSide-20k will have ultra-low backgrounds than can be measured in situ, giving sensitivity to WIMP-nucleon cross sections of \(1.2 \times 10^{-47}\) cm2 (\(1.1 \times 10^{-46}\) cm2) for WIMPs of 1 TeV/c2 (10 TeV/c2) mass, to be achieved during a 5 yr run producing an exposure of 100 t yr free from any instrumental background.