Superconducting detector arrays have become the standard technology for the current generation of millimeter-wave and submm-wave astronomical instruments on individual (single dish) telescopes. ...Superconducting heterodyne arrays are used for spectroscopic surveys and direct detector arrays are used for photometric imaging and low resolution spectroscopy. Most of these direct detector arrays consist of bolometers with superconducting thermometers called Transition Edge Sensors (TES) and are read out with multiplexed superconducting quantum interference device (SQUID) current amplifiers. Another superconducting detector technology called Kinetic Inductance Detectors (KIDs) is starting to be used in new astronomical instruments as well. This review describes the properties of these two types of detectors and the prospects for future development of both types of technologies toward larger pixel counts and more capable instruments.
The AzTEC mm-wavelength camera Wilson, G. W.; Austermann, J. E.; Perera, T. A. ...
Monthly notices of the Royal Astronomical Society,
20/May , Letnik:
386, Številka:
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AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Here, we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report ...on several performance metrics measured during a three-month observing campaign at the James Clerk Maxwell Telescope and conclude with our plans for AzTEC as a facility instrument on the Large Millimetre Telescope.
We present the first results from a confusion-limited map of the Great Observatories Origins Deep Survey-South (GOODS-S) taken with the AzTEC camera on the Atacama Submillimeter Telescope Experiment. ...We imaged a field to a 1σ depth of 0.48–0.73 mJy beam−1, making this one of the deepest blank-field surveys at mm-wavelengths ever achieved. Although by traditional standards our GOODS-S map is extremely confused due to a sea of faint underlying sources, we demonstrate through simulations that our source identification and number counts analyses are robust, and the techniques discussed in this paper are relevant for other deeply confused surveys. We find a total of 41 dusty starburst galaxies with signal-to-noise ratios S/N ≥ 3. 5 within this uniformly covered region, where only two are expected to be false detections, and an additional seven robust source candidates located in the noisier (1σ≈ 1 mJy beam−1) outer region of the map. We derive the 1.1 mm number counts from this field using two different methods: a fluctuation or “P(d)” analysis and a semi-Bayesian technique and find that both methods give consistent results. Our data are well fit by a Schechter function model with . Given the depth of this survey, we put the first tight constraints on the 1.1 mm number counts at S1.1 mm= 0.5 mJy, and we find evidence that the faint end of the number counts at from various SCUBA surveys towards lensing clusters are biased high. In contrast to the 870 μm survey of this field with the LABOCA camera, we find no apparent underdensity of sources compared to previous surveys at 1.1 mm; the estimates of the number counts of SMGs at flux densities >1 mJy determined here are consistent with those measured from the AzTEC/SHADES survey. Additionally, we find a significant number of SMGs not identified in the LABOCA catalogue. We find that in contrast to observations at λ≤ 500 μm, MIPS 24 μm sources do not resolve the total energy density in the cosmic infrared background at 1.1 mm, demonstrating that a population of z≳ 3 dust-obscured galaxies that are unaccounted for at these shorter wavelengths potentially contribute to a large fraction (∼2/3) of the infrared background at 1.1 mm.
We present results of a new deep 1.1 mm survey using Bolocam, a millimeter-wavelength bolometer array camera designed for mapping large fields at fast scan rates, without chopping. A map, galaxy ...candidate list, and derived number counts are presented. This survey encompasses 324 arcmin super(2) to an rms noise level (filtered for point sources) of s sub(1.1 mm) 1.4 mJy beam super(-1) and includes the entire regions surveyed by the published 8 mJy 850 km JCMT SCUBA and 1.2 mm IRAM MAMBO surveys. We reduced the data using a custom software pipeline to remove correlated sky and instrument noise via a principal component analysis. Extensive simulations and jackknife tests were performed to confirm the robustness of our source candidates and estimate the effects of false detections, bias, and completeness. In total, 17 source candidates were detected at a significance .3.0 s, with six expected false detections. Nine candidates are new detections, while eight candidates have coincident SCUBA 850 km and/or MAMBO 1.2 mm detections. From our observed number counts, we estimate the underlying differential number count distribution of submillimeter galaxies and find it to be in general agreement with previous surveys. Modeling the spectral energy distributions of these submillimeter galaxies after observations of dusty nearby galaxies suggests extreme luminosities of L = (1.0-1.6) x 10 super(13) L sub( )and, if powered by star formation, star formation rates of 500-800 M sub( )yr super(-1).
Superconducting nanowires are widely used as sensitive single photon detectors with wide spectral coverage and high timing resolution. We describe a demonstration of an array of dc-biased ...superconducting nanowire single photon detectors read out with a microwave multiplexing circuit. In this design, each individual nanowire is part of a resonant LC circuit where the inductance is dominated by the kinetic inductance of the nanowire. The circuit also contains two parallel plate capacitors, one of them is in parallel with the inductor and the other is coupled to a microwave transmission line that carries the signals to a cryogenic low-noise amplifier. All of the nanowires are connected via resistors to a single dc bias line that enables the nanowires to be current biased close to their critical current. When a photon hits a nanowire, it creates a normal hotspot that produces a voltage pulse across the LC circuit. This pulse rings down at the resonant frequency of the LC circuit over a time period that is fixed by the quality factor. We present measurements of an array of these devices and an evaluation of their performance in terms of frequency and time response.
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