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Author: Ganschow, S. × DDC: 530 ×

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    Cryogenic characterization of a LiAlO 2 crystal and new results on spin-dependent dark matter interactions with ordinary matter: CRESST Collaboration
    (Berlin ; Heidelberg : Springer, 2020) Abdelhameed, A.H.; Angloher, G.; Bauer, P.; Bento, A.; Bertoldo, E.; Breier, R.; Bucci, C.; Canonica, L.; D’Addabbo, A.; Di Lorenzo, S.; Erb, A.; Feilitzsch, F.V.; Iachellini, N.F.; Fichtinger, S.; Fuchs, D.; Fuss, A.; Ghete, V.M.; Garai, A.; Gorla, P.; Hauff, D.; Ješkovský, M.; Jochum, J.; Kaizer, J.; Kaznacheeva, M.; Kinast, A.; Kluck, H.; Kraus, H.; Langenkämper, A.; Mancuso, M.; Mokina, V.; Mondragon, E.; Olmi, M.; Ortmann, T.; Pagliarone, C.; Palušová, V.; Pattavina, L.; Petricca, F.; Potzel, W.; Povinec, P.; Pröbst, F.; Reindl, F.; Rothe, J.; Schäffner, K.; Schieck, J.; Schipperges, V.; Schmiedmayer, D.; Schönert, S.; Schwertner, C.; Stahlberg, M.; Stodolsky, L.; Strandhagen, C.; Strauss, R.; Usherov, I.; Wagner, F.; Willers, M.; Zema, V.; Zeman, J.; Brützam, M.; Ganschow, S.
    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 350MeV/c2 and 1.50GeV/c2. 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. © 2020, The Author(s).
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    Lithium-Containing Crystals for Light Dark Matter Search Experiments
    (Dordrecht : Springer Science + Business Media B.V. , 2020) Bertoldo, E.; Abdelhameed, A.H.; Angloher, G.; Bauer, P.; Bento, A.; Breier, R.; Bucci, C.; Canonica, L.; D’Addabbo, A.; Di Lorenzo, S.; Erb, A.; Feilitzsch, F.V.; Ferreiro Iachellini, N.; Fichtinger, S.; Fuchs, D.; Fuss, A.; Gorla, P.; Hauff, D.; Ješkovský, M.; Jochum, J.; Kaizer, J.; Kinast, A.; Kluck, H.; Kraus, H.; Langenkämper, A.; Mancuso, M.; Mokina, V.; Mondragon, E.; Olmi, M.; Ortmann, T.; Pagliarone, C.; Palušová, V.; Pattavina, L.; Petricca, F.; Potzel, W.; Povinec, P.; Pröbst, F.; Reindl, F.; Rothe, J.; Schäffner, K.; Schieck, J.; Schipperges, V.; Schmiedmayer, D.; Schönert, S.; Schwertner, C.; Stahlberg, M.; Stodolsky, L.; Strandhagen, C.; Strauss, R.; Usherov, I.; Willers, M.; Zema, V.; Zeman, J.; Brützam, M.; Ganschow, S.
    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 LiAlO2, a target crystal never used before in cryogenic experiments.
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    Huge impact of compressive strain on phase transition temperatures in epitaxial ferroelectric KxNa1-xNbO3 thin films
    (Melville, NY : American Inst. of Physics, 2019) Von Helden, L.; Bogula, L.; Janolin, P.-E.; Hanke, M.; Breuer, T.; Schmidbauer, M.; Ganschow, S.; Schwarzkopf, J.
    We present a study in which ferroelectric phase transition temperatures in epitaxial KxNa1-xNbO3 films are altered systematically by choosing different (110)-oriented rare-earth scandate substrates and by variation of the potassium to sodium ratio. Our results prove the capability to continuously shift the ferroelectric-to-ferroelectric transition from the monoclinic MC to orthorhombic c-phase by about 400 °C via the application of anisotropic compressive strain. The phase transition was investigated in detail by monitoring the temperature dependence of ferroelectric domain patterns using piezoresponse force microscopy and upon analyzing structural changes by means of high resolution X-ray diffraction including X-ray reciprocal space mapping. Moreover, the temperature evolution of the effective piezoelectric coefficient d33,f was determined using double beam laser interferometry, which exhibits a significant dependence on the particular ferroelectric phase. © 2019 Author(s).