Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 9: SC: Poster Session

TT 9.57: Poster

Monday, March 22, 2010, 14:00–18:00, Poster A

Metallic magnetic calorimeters for high-precission QED tests at GSI/FAIR — •Christian Pies, Andreas Pabinger, Sebastian Kempf, Andreas Fleischmann, Loredana Gastaldo, and Christian Enss — Kirchhoff-Institut für Physik, Universität Heidelberg, Germany.

Quantum electrodynamics belongs to the best tested and established theories in modern physics. However, the evaluation of high order processes, as necessary in strong fields, is still demanding. A precission test of QED in strong fields is the comparison of the calculated and measured Lamb-shift of the ground state in hydrogen-like heavy ions.

For the spectroscopy of hydrogen-like Uranium at GSI/FAIR, we recently started the development of a detector for hard x-rays emitted during the transition into the ground state. The detector consists of four independent, gradiometric metallic magnetic calorimeters (MMCs) forming a linear 8-pixel array and is completely micro-fabricated. Each pixel covers an area of 1 mm² and is equipped with a 200 µm thick electrodeposited gold absorber. The detectors are designed to provide an energy resolution better than 30 eV in the relevant energy range up to 100 keV with a stopping power larger than 85 %.

We present the considerations which lead to our present detector design, the methods used for the fabrication of the MMC array as well as first characterization measurements.