Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 29: Poster Session: Cryogenic Particle Detectors and Cyotechnique
TT 29.8: Poster
Montag, 12. März 2018, 15:00–19:00, Poster B
Polar-maXs: Micro-calorimeter based x-ray polarimeters — C. Schötz1, D. Hengstler1, S. Kempf1, L. Gastaldo1, A. Fleischmann1, C. Enss1, G. Weber2,3, R. Märtin2,3, O.M. Herdrich4, Th. Stöhlker2,3,4, and •S. Allgeier1 — 1KIP, Heidelberg University — 2Helmholtz Institute Jena — 3GSI Darmstadt — 4Jena University
We are developing the x-ray detector system polar-maXs, which will combine for the first time the high energy resolution, large dynamic range and excellent linearity of magnetic micro-calorimeters with the idea of a Compton- or Rayleigh-polarimeter.
The x-ray polarimeter comprises two layers. The first layer consists of a scatterer behind a corresponding collimator. Depending on the energy range of interest and whether Compton or Rayleigh scattering is to be used, this scatterer are fabricated from low-Z or high-Z material. The active scatter area is 32mm in diameter. The second layer is the detector itself which is based on microfabricated metallic magnetic calorimeters (MMC). The scattered x-rays are detected by an array of 64 x-ray absorbers and read-out by 64 paramagnetic temperature sensors. The latter are arranged to form a rectangular frame which is protected from direct x-ray hits by the collimator. Each absorber covers an area of 1.250mm x 1.250mm and is made of 30 micrometer thick gold, to guarantee high stopping power for x-rays with energies up to 30 keV and an energy resolution of better than 20eV (FWHM) in the complete energy range. We discuss the results of Monte-Carlo simulations for a variety of scatter materials as well as first measurements at 20mK in a dilution refrigerator.