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Experimental techniques for the study of the CMB anisotropy and polarization, and the Sunyaev-Zel'dovich effect

Observational cosmology is one of the most active fields in modern astrophysics. Following the discovery of the microwave background by Penzias and Wilson (Penzias & Wilson 1965) and the success of COBE-DMR, research groups throughout the world have pursued the study of the primary and secondary anisotropics in the cosmic microwave background (CMB). Instrumentation designed specifically for these studies have resulted in ever more sensitive detections of the CMB fingerprints. This thesis describes work on three bolometric instruments operating at cryogenic temperatures that have been designed to study the CMB. We present a design study with initial assembly and testing on the first of these, a new type of instrument---the millimetre-wave bolometric interferometer prototype (MBI-P). This instrument combines two well-known techniques: bolometric detection and interferometry, and could be used to observe the CMB on small angular scales with high sensitivity. Our investigation includes the design of the optics, cryogenics and mechanics of the prototype. We present a prototype that has a clear potential to demonstrate the technology involved. We then describe our contribution to Polatron, a bolometric polarimeter designed to study the polarization of the CMB. We assess its performance by analysing the noise coupling between the mechanical cryocooler and the bolometers. We demonstrate that Polatron is not able to fulfil the technical requirements in terms of sensitivity, necessary to achieve its science goal. Finally, we discuss the thermal behaviour of the cold-amplifier stage of Bolocam---a millimetre-wave bolometric camera, now operating at the Caltech sub-millimetre observatory (CSO), one of whose main scientific objective is the study of the CMB secondary signatures. Having modified the cryogenic design, we measure and analyse its performance which has significantly lowered the cryogen consumption.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:583461
Date January 2004
CreatorsRossinot, Philippe
PublisherCardiff University
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://orca.cf.ac.uk/55923/

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