|
QUIET is an astronomy experiment to study the polarization of the cosmic microwave background radiation.〔 QUIET stands for Q/U Imaging ExperimenT. The Q/U in the name refers to the ability of the telescope to measure the Q and U Stokes parameters simultaneously. QUIET is located at an elevation of 5,080 metres (16,700 feet) at Llano de Chajnantor Observatory in the Chilean Andes.〔 It began observing in late 2008 and finished observing in December 2010. QUIET is the result of an international collaboration that has its origins in the CAPMAP, Cosmic Background Imager (CBI) and QUaD collaborations. The collaboration consists of 7 groups in the United States (the California Institute of Technology, the University of Chicago, Columbia University, the Jet Propulsion Laboratory, the University of Miami, Princeton University and Stanford University), 4 groups in Europe (the University of Manchester, the Max-Planck-Institut für Radioastronomie Bonn, the University of Oslo and the University of Oxford) and one group in Japan (KEK; the first time a Japan group has been involved in CMB studies). Other members of the collaboration are from the University of California, Berkeley, the Goddard Space Flight Center and the Harvard-Smithsonian Center for Astrophysics. ==Instrument== QUIET had arrays of detectors at two frequencies: 43 GHz (Q band) and 95 GHz (W band). It used four telescopes, three of which were purpose-built 2 m ones with the other being the 7 m Crawford Hill telescope used for CAPMAP. As a result, it will have angular resolutions between a few arcminutes and several degrees. The detectors are mass-produced coherent correlation polarimeters.〔〔 The instrument was constructed in three phases. The first phase consisted of a 7-element 95 GHz array to demonstrate the technology. The second phase aims to mount a 91-element 95 GHz array (with 18 GHz bandwidth) and a 19-element 43 GHz array (with 8 GHz bandwidth) on 1.4 m cassegrain telescopes, mounted on what is currently the CBI platform. It is expected that these will start observing in 2008. The third phase aims to construct four further arrays by around 2010. Two of these will be at 43 GHz, with 91 elements each, and the other two will be at 95 GHz, with 397 elements each. These will then be mounted on three 2 m dishes on the CBI platform and the 7 m telescope.〔Samtleben (2008)〕 The instrument is located at a height of 5,080 m at Llano de Chajnantor Observatory in the Chilean Andes. The site is owned by the Chilean government, and is leased to the Atacama Large Millimeter Array. The site was selected due to the altitude, current infrastructure and accessibility, as well as the low humidity of the site, which reduces the contamination of the detected signals by the atmosphere. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「QUIET」の詳細全文を読む スポンサード リンク
|