Cryogenic characterization of a $$\hbox {LiAlO}_{2}$$LiAlO2 crystal and new results on spin-dependent dark matter interactions with ordinary matter

In this work, a first cryogenic characterization of a scintillating $$\hbox {LiAlO}_{2}$$ 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 fur Kristallzuchtung (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 $$\hbox {LiAlO}_{2}$$ at cryogenic temperatures. The second achieved an energy threshold of ( $$213.02\pm 1.48$$ ) eV which allows setting a competitive limit on the spin-dependent dark matter particle-proton scattering cross section for dark matter particle masses between $$350\,\hbox {MeV/c}^{2}$$ and $$1.50\,\hbox {GeV/c}^{2}$$ . Secondly, a detector module with a 373 g $$\hbox {LiAlO}_{2}$$ 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.