Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 21: Superconductivity: Poster Session

TT 21.50: Poster

Monday, March 16, 2015, 15:00–18:00, Poster B

Metallic Magnetic Calorimeters for high resolution X-ray spectroscopy — •M. Krantz, D. Hengstler, J. Geist, C. Schötz, K. Hassel, S. Hendricks, M. Keller, S. Kempf, L. Gastaldo, A. Fleischmann, and C. Enss — KIP Heidelberg University.

We develop microfabricated, energy dispersive particle detector arrays based on metallic magnetic calorimeters (MMCs) for high resolution x-ray spectroscopy to challenge bound-state QED calculations. Our MMCs are operated at about T=30 mK and use a paramagnetic temperature sensor, read-out by a SQUID, to measure the energy deposited by single x-ray photons. We discuss the physics of MMCs, the detector performance and the cryogenic setups for two different detector arrays. We present their microfabrication layouts with focus on challenges like the heatsinking of each pixel of the detector and the overhanging absorbers. The maXs-20 detector is a linear 1x8-pixel array with excellent linearity in its designated energy range up to 20 keV and unsurpassed energy resolution of 1.6 eV for 6 keV x-rays. MaXs-20 operated in a highly portable pulse tube cooled ADR setup has already been used at the EBIT facilities of the MPI-K for new reference measurements of V-like and Ti-like tungsten. The maXs-30 detector currently in development is a 8x8-pixel 2d-array with an active detection area of 16 mm² and is designed to detect x-rays up to 50 keV with a designated energy resolution below 5 eV. MaXs-30 will be operated in a cryogen free 3He/4He-dilution refrigerator at the tip of a 40 cm long cold finger at T=20 mK.