22 July 2008 Test of x-ray microcalorimeters with bilayer absorbers
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Superconducting absorbers for thermal X-ray microcalorimeters should convert into thermalized phonons and transfer to the thermal sensor most of the energy deposited by single photons, on a time scale as short as a few tens of microseconds. Since deposition of X-ray energy in a superconductor produces quasiparticles by breaking up of Cooper pairs, the thermalization efficiency depends on the time scale on which they survive within the absorber volume, trapping part of the absorbed energy. According to the predicted values of their microscopic parameters, in many standard type-I superconducting metals the quasiparticle life time at very low temperatures results too long to allow for recombination on the relatively short time scale of the thermal sensors. In type-II superconductors the existence of a mixed state with Abrikosov vortices could speed up the recombination process and increase the efficiency of thermalization. We discuss this topic by presenting experimental results of laboratory tests conducted on tantalum and lead-bismuth absorbers in a comparison with an absorber made of gold, where no trapping is expected.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
E. Perinati, M. Barbera, J. Beeman, A. Collura, L. Dumoulin, C. Pigot, L. Piro, E. Silver, S. Varisco, "Test of x-ray microcalorimeters with bilayer absorbers", Proc. SPIE 7021, High Energy, Optical, and Infrared Detectors for Astronomy III, 70211M (22 July 2008); doi: 10.1117/12.787941; https://doi.org/10.1117/12.787941


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