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Développement d'une caméra pour la radioastronomie millimétrique

Abstract : Millimetre-wave astronomy presents a particular interest for the understanding of the history and evolution of our universe, especially thanks to the anisotropies of the Cosmic Microwave Background and the mapping of galaxies and clusters of galaxies. Until a few years ago, collections of individual pixels detectors were used to cover small focal planes. The current need for instruments running arrays of thousands of detectors calls for a new philosophy. The two main issues concern the fabrication and the readout of the detectors, to be used in an environment constrained by the cryogenic set-up required for highly sensitive detection. After a brief introduction to the astronomical goals and the related instrumental constraints, this document presents the conception of a camera dedicated to the 2 mm (150 GHz) atmospheric window of the 30m IRAM radio-telescope. Cryogenics, optics, electronics and detectors will be discussed. A special attention is given to the set up of a platform dedicated to the optical characterization of the detectors. We present arrays of 204 bolometers, optically coupled by planar antennas and read with thermometers made of a thin layer of NbSi. Electrical and optical characterizations are discussed. A multiplexed readout prototype has also been implemented, and preliminary measurements of about 80 detectors are discussed. We also present arrays of Kinetic Inductance Detectors (KIDs). The accent is put on the readout procedure, still not completely optimized due to the recent use of such detectors. The obtained performances on KIDs have led us to an engineering run at the IRAM telescope, in October 2009. This campaign was successful, and both technical and scientific results are presented. An overall sensitivity of 1.2 10E-15 W/sqrt(Hz)/beam was measured on the sky. After one year of improvements, a new version of the instrument is to be tested in October 2010. It will enable a simultaneous observation at 1 and 2 mm, with two arrays of 144 detectors each and a full sampling of the focal plan.
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https://tel.archives-ouvertes.fr/tel-00589869
Contributor : Aurélien Bideaud <>
Submitted on : Monday, May 2, 2011 - 3:45:01 PM
Last modification on : Thursday, November 19, 2020 - 1:01:03 PM
Long-term archiving on: : Wednesday, August 3, 2011 - 2:46:31 AM

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  • HAL Id : tel-00589869, version 1

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Aurélien Bideaud. Développement d'une caméra pour la radioastronomie millimétrique. Physique [physics]. Université de Grenoble, 2010. Français. ⟨tel-00589869⟩

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