6 research outputs found

    Prototype finline-coupled TES bolometers for CLOVER

    Full text link
    CLOVER is an experiment which aims to detect the signature of gravitational waves from inflation by measuring the B-mode polarization of the cosmic microwave background. CLOVER consists of three telescopes operating at 97, 150, and 220 GHz. The 97-GHz telescope has 160 feedhorns in its focal plane while the 150 and 220-GHz telescopes have 256 horns each. The horns are arranged in a hexagonal array and feed a polarimeter which uses finline-coupled TES bolometers as detectors. To detect the two polarizations the 97-GHz telescope has 320 detectors while the 150 and 220-GHz telescopes have 512 detectors each. To achieve the target NEPs (1.5, 2.5, and 4.5x10^-17 W/rtHz) the detectors are cooled to 100 mK for the 97 and 150-GHz polarimeters and 230 mK for the 220-GHz polarimeter. Each detector is fabricated as a single chip to ensure a 100% operational focal plane. The detectors are contained in linear modules made of copper which form split-block waveguides. The detector modules contain 16 or 20 detectors each for compatibility with the hexagonal arrays of horns in the telescopes' focal planes. Each detector module contains a time-division SQUID multiplexer to read out the detectors. Further amplification of the multiplexed signals is provided by SQUID series arrays. The first prototype detectors for CLOVER operate with a bath temperature of 230 mK and are used to validate the detector design as well as the polarimeter technology. We describe the design of the CLOVER detectors, detector blocks, and readout, and present preliminary measurements of the prototype detectors performance.Comment: 4 pages, 6 figures; to appear in the Proceedings of the 17th International Symposium on Space Terahertz Technology, held 10-12 May 2006 in Pari

    Optimisation of performance of dispersants in aqueous titanium slips

    No full text
    Slip casting is a well-established ceramic casting technique used for large scale fabrication of ceramic products with complex shapes. A homogenous slip with a desired level of stability is required, which is controlled using a dispersant. This paper describes the selection and optimisation of various dispersants used to produce Ti powder slips. A consideration of the effect of concentration and pH of the solvent on the dispersion of anionic polyelectrolyte dispersants (Dispex N-40, Synthecol SD375 & Dolapix CE64) was examined by measuring the sedimentation height and rate, the streaming potential and the slip viscosity. It was found that Dolapix CE64 showed the best deflocculating effect at 0.3dw.% with pH of 7. In particular, the measurements on Dolapix CE64 gave consistent results. This indicated that Dolapix CE64 is an effective dispersant in the preparation of a titanium slip

    TES imaging array technology for ClOVER.

    Get PDF
    Clover is an experiment which aims to detect the signature of gravitational waves from inflation by measuring the B-mode polarization of the cosmic microwave background. Clover consists of three telescopes operating at 97, 150, and 220 GHz. The 97-GHz telescope has 160 horns in its focal plane while the 150 and 220-GHz telescopes have 256 horns each. The horns are arranged in a hexagonal array and feed a polarimeter which uses finline-coupled TES bolometers as detectors. To detect the two polarizations the 97-GHz telescope has 320 detectors while the 150 and 220-GHz telescopes have 512 detectors each. To achieve the required NEPs the detectors are cooled to 100 mK for the 97 and 150-GHz polarimeters and 230 mK for the 220-GHz polarimeter. Each detector is fabricated as a single chip to guarantee fully functioning focal planes. The detectors are contained in linear modules made of copper which form split-block waveguides. The detector modules contain 16 or 20 detectors each for compatibility with the hexagonal arrays of horns in the telescopes' focal planes. Each detector module contains a time-division SQUID multiplexer to read out the detectors. Further amplification of the multiplexed signals is provided by SQUID series arrays. The first prototype detectors for Clover operate with a bath temperature of 230 mK and are used to validate the detector design as well as the polarimeter technology. We describe the design of the Clover detectors, detector blocks, and readout, and give an update on the detector development. Copyright 2006 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.Science, Faculty ofPhysics and Astronomy, Department ofReviewedFacult
    corecore