Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity - Cryodetectors

TT 30.2: Talk

Thursday, March 29, 2007, 17:15–17:30, H20

Microfabricated magnetic calorimeter with meander shaped pickup coil — •A. Burck, S. Kempf, M. Linck, H. Rotzinger, S. Schäfer, J. Porst, T. Wolf, A. Fleischmann, L. Gastaldo, and C. Enss — Kirchhoff-Institut für Physik, Heidelberg, Germany

Metallic magnetic calorimeters (MMC) combine the high spectral resolution of crystal spectrometer and the high quantum efficiency of solid state spectrometer. Recently we demonstrated an energy resolution of 2.7 eV for 6 keV photons. This makes MMCs a promising and powerful tool for many applications where photons or energetic massive particles have to be detected. However, in order to fulfill all requirements of these applications and to allow to reach the maximum resolving power a consequent microfabrication of the MMC detectors is needed.

We present our first fully microfabricated MMC which consists of an absorber, a 3 µ m thick sputter deposited paramagnetic AuEr temperature sensor and a meander shaped niobium thin film pickup coil. Deposition of energy in the absorber causes a rise in temperature and results in a change of magnetisation of the paramagnetic sensor which is measured by a low noise high bandwidth dc-SQUID. By using a new optimized persistent current switch a large field current can be frozen in the pickup coil which produces an inhomogeneous magnetic field within the volume of the sensor. The sputter deposited AuEr films we report on are working well and show the properties of bulk material. The performance of our MMCs with such films agree well with the numerically simulated behavior.