Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 55: Poster Session: Superconductivity 2

TT 55.20: Poster

Wednesday, March 22, 2017, 15:00–19:00, P2-OG3

Solid State Physics and Engineering to Push the Resolving Power of Magnetic Calorimeters Beyond 10 000 — •M. Krantz, J. Geist, M. Keller, D. Hengstler, C. Schötz, F. Mücke, S. Kempf, L. Gastaldo, A. Fleischmann, and C. Enss — Kirchoff-Institute for Physics, Heidelberg University

Metallic magnetic calorimeters (MMC’s) are energy dispersive particle detectors operated below 100 mK which excel in energy resolution, dynamic range and linearity. They use a paramagnetic temperature sensor to convert the energy deposited by means of photon absorption into a magnetic flux change in a SQUID, which is read-out as a voltage signal with low noise and large bandwidth. During the last decade we have been optimizing the signal size of MMCs by numerical optimizations and by the consequent use of micro-fabrication techniques, while lowering the readout noise close to quantum limit. The combination of both rewarded us with a world record instrumental linewidth of 1.6 eV (FWHM) for 6 keV X-rays, measured with our maXs-20 detector, a 1x8 pixel array. We summerize the physics of MMCs focusing on solid state effects, we present application-oriented microfabrication processes and cryogenic setups and we show recent results of our X-ray detectors. This includes the maXs-30 detector, an 8x8 pixel array optimized for X-rays up to 30 keV and a new design, which places the temperature sensor directly in a SQUID for maximized signal coupling with an expected instrumental linewidth below 1 eV (FWHM) for X-rays up to 10 keV. Our detectors are operated in a cryogen free 3He/4He-dilution refrigerator at the tip of a 40 cm long cold finger at T=20 mK.