摘要 :
NIST produces large-format, dual-polarization-sensitive detector arrays for a broad range of frequencies (30-1400 GHz). Such arrays enable a host of astrophysical measurements. Detectors optimized for cosmic microwave background o...
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NIST produces large-format, dual-polarization-sensitive detector arrays for a broad range of frequencies (30-1400 GHz). Such arrays enable a host of astrophysical measurements. Detectors optimized for cosmic microwave background observations are monolithic, polarization-sensitive arrays based on feedhorn and planar Nb antenna-coupled transition-edge superconducting (TES) bolometers. Recent designs achieve multiband, polarimetric sensing within each spatial pixel. In this proceeding, we describe our multichroic, feedhorn-coupled design; demonstrate performance at 70-380 GHz; and comment on current developments for implementation of these detector arrays in the advanced Atacama Cosmology Telescope receiver
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摘要 :
Upcoming experiments aim to produce high fidelity polarization maps of the cosmic microwave background. To achieve the required sensitivity, we are developing monolithic, feedhorn-coupled transition edge sensor polarimeter arrays ...
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Upcoming experiments aim to produce high fidelity polarization maps of the cosmic microwave background. To achieve the required sensitivity, we are developing monolithic, feedhorn-coupled transition edge sensor polarimeter arrays operating at 150 GHz. We describe this focal plane architecture and the current status of this technology, focusing on single-pixel polarimeters being deployed on the Atacama B-mode Search (ABS) and an 84-pixel demonstration feedhorn array backed by four 10-pixel polarimeter arrays. The feedhorn array exhibits symmetric beams, cross-polar response less than -23 dB and excellent uniformity across the array. Monolithic polarimeter arrays, including arrays of silicon feedhorns, will be used in the Atacama Cosmology Telescope Polarimeter (ACTPol) and the South Pole Telescope Polarimeter (SPTpol) and have been proposed for upcoming balloon-borne instruments.
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A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97mCi (sup 22)Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered...
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A high intensity variable energy positron beam has been constructed at Brookhaven National Laboratory (BNL). Positrons from a 97mCi (sup 22)Na source are moderated by a thin layer of solid neon. A magnetic guiding system delivered up to 5(times)10(sup 6)e(sup +)/sec to an experiment. Currently tests are under way to facilitate the operation with the magnetic guiding system or -- for other experimental sites -- with an electrostatic beam transport. The electrostatic lenses are fabricated from (mu)-metal. No compensation of the earth magnetic field is required. Several experiments can utilize the beam on a time sharing basis. In the near future the source will be replaced by (sup 64)Cu which has a much higher activity. Beam intensities up to 10(sup 9)e(sup +)/sec are expected.
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This is the Final Engineering Report on Phase 2.2 work on the ultrasonic subsystem for the trend inspection station for printed circuit board solder joints. The report discusses activities during this contract period in six major ...
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This is the Final Engineering Report on Phase 2.2 work on the ultrasonic subsystem for the trend inspection station for printed circuit board solder joints. The report discusses activities during this contract period in six major areas. Probe assemblies have been refined by redesigning both receiver and transmitter to permit closer spacing of these probes for inspection of small joints. In addition, transmitter design has resulted in a new style probe. Based in part on the characteristics of ultrasonic spectra of the solder joint types of interest, and in part on the mental processes used in visual evaluation of joint spectra to make a judgment on joint quality, several algorithms have been investigated for computerizing the decision making process. A simple but effective algorithm has been devised for use with the latest probe set in inspecting good lap solder joints and those with heel cracks. A probe manipulator for the pilot model of the ultrasonic subsystem was designed and constructed during this contract period. It was used in some of the later experimentation in this period directed to defining performance capability.
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