Abstract : Precise measurements of the cosmic microwave background (CMB) is crucial to cosmology, since any proposed model of the Universe must account for the features of this radiation. E_cient very large bolometer arrays (> 10,000 pixels) constitute an important challenge for CMB observations and are actually developed by many groups worldwide. We present here an explorative new bolometer design based on a structure that simplifies the fabrication process and exhibits high sensitivity. This innovative device replaces delicate membrane-based structures and eliminates the mediation of phonons: the incoming energy is directly captured and measured in the electron bath of an appropriate sensor and the thermal decoupling is achieved via the intrinsic electron-phonon decoupling of the sensor at very low temperature. Reported results come from a 204-pixel matrix of Nb (x) Si1-x transition edge sensors with a meander structure fabricated on a 2-inch silicon wafer using electron-beam co-evaporation and standard lithography process. To validate the application to CMB measurements, we have realized an optical calibration of our sample in the focal plane of a dilution cryostat test bench.
http://hal.in2p3.fr/in2p3-00703213
Contributor : Christine Hadrossek <>
Submitted on : Friday, June 1, 2012 - 10:59:05 AM Last modification on : Friday, December 18, 2020 - 1:08:03 PM
S. Marnieros, C. Nones, L. Dumoulin, L. Berge, O. Rigaut, et al.. Electron-Phonon Decoupling NbSi CMB Bolometers. Journal of Low Temperature Physics, Springer Verlag (Germany), 2012, 167, pp.846-851. ⟨10.1007/s10909-012-0532-8⟩. ⟨in2p3-00703213⟩