Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity - Poster Session

TT 30.65: Poster

Montag, 31. März 2014, 15:00–19:00, P2

Advances in the development of microstructured Magnetic Penetration Thermometers (MPT) — •J. Geist, S. Kempf, L. Gastaldo, A. Fleischmann, and C. Enss — KIP Heidelberg University

We recently started the development of microfabricated calorimetric detectors with magnetic penetration thermometers (MPT). MPTs make use of the steep temperature dependence of the magnetic penetration depth and the critical magnetic field of a superconducting sensor to monitor its temperature. When the sensor is placed in a weak magnetic bias field, the temperature rise following the absorption of a particle in the detector leads to a change of magnetic flux density B(r) inside the sensor and in its vicinity, which is detected as a magnetic flux change in the pickup coil of a sensitive magnetometer and serves as a measure of the absorbed energy.

We present numerical design studies as well as first experimental tests of microfabricated MPT sensor layers, patterned to form arrays of micron wide lines and dots which can be read out e.g. using meander-shaped pickup coils. We show that hysteresis effects as previously observed in MPT devices with large-area superconducting films can be completely suppressed. We also show that elemental superconductors needs to be deposited with high film quality to allow for a high detector sensitivity and therefore energy resolution. Finally, we show that the requirements on the film quality is somehow relaxed when the MPT sensor is made of thick S/N bilayers such as Al/Au or Al/Ag.