Characterising the SCUBA-2 superconducting bolometer arrays
Dan BintleyMichael J. MacIntoshW. S. HollandPer FribergCraig WaltherDavid AtkinsonDennis KellyXiaofeng GaoP. A. R. AdeWilliam GraingerJulian S. HouseLorenzo MoncelsiM. HollisterAdam L. WoodcraftCamelia DunareWilliam ParkesA.J. WaltonK. D. IrwinG. C. HiltonMichael D. NiemackC. D. ReintsemaM. AmiriB. BurgerM. HalpernMatthew HasselfieldJeff T. HillJ. B. KyciaChas MugfordLauren Persaud
13
Citation
7
Reference
10
Related Paper
Citation Trend
Abstract:
SCUBA-2 is a state of the art 10,000 pixel submillimeter camera installed and being commissioned at the James Clerk Maxwell Telescope (JCMT) providing wide-field simultaneous imaging at wavelengths of 450 and 850 microns. At each wavelength there are four 32 by 40 sub-arrays of superconducting Transition Edge Sensor (TES) bolometers, each packaged with inline SQUID multiplexed readout and amplifier. In this paper we present the results of characterising individual 1280 bolometer science grade sub-arrays, both in a dedicated 50mk dilution refrigerator test facility and in the instrument installed at the JCMT.Keywords:
Transition edge sensor
Large format
Transition edge sensor
Large format
Cite
Citations (6)
We present results of the first tests on a 1280 pixel superconducting bolometer array, a prototype for SCUBA‐2, a sub‐mm camera being built for the James Clerk Maxwell Telescope in Hawaii. The bolometers are TES (transition edge sensor) detectors; these take advantage of the large variation of resistance with temperature through the superconducting transition. To keep the number of wires reasonable, a multiplexed read‐out is used. Each pixel is read out through an individual DC SQUID; room temperature electronics switch between rows in the array by biasing the appropriate SQUIDs in turn. Arrays of 100 SQUIDs in series for each column then amplify the output. Unlike previous TES arrays, the multiplexing elements are located beneath each pixel, making large arrays possible, but construction more challenging. The detectors are constructed from Mo/Cu bi‐layers; this technique enables the transition temperature to be tuned using the proximity effect by choosing the thickness of the normal and superconducting materials. To achieve the required performance, the detectors are operated at a temperature of approximately 120 mK. We describe the results of a basic characterisation of the array, demonstrating that it is fully operational, and give the results of signal to noise measurements.
Transition edge sensor
Biasing
Cite
Citations (1)
SCUBA-2 is a submillimeter camera being built for the James Clerk Maxwell Telescope in Hawaii. Bringing CCD style imaging to the submillimeter for the first time, with over 10000pixels, it will provide a revolutionary improvement in sensitivity and mapping speed. We present results of the first tests on a prototype 1280pixel SCUBA-2 subarray; the full instrument will be made up of eight such subarrays. The array is made up of transition edge sensor (TES) detectors, with Mo∕Cu bilayers as the sensing element. To keep the number of wires reasonable, a multiplexed readout is used. Unlike previous TES arrays, an in-focal plane multiplexer configuration is used, in which the multiplexing elements are located beneath each pixel. To achieve the required performance, the detectors are operated at a temperature of approximately 120mK. We describe the results of a basic electrical and optical characterization of the array, demonstrating that it is fully operational. Noise measurements were made on several pixels and gave a noise equivalent power below 2.5×10−17WHZ−0.5, within the requirements for SCUBA-2. The construction of the testbed used to carry out these measurements is also described.
Transition edge sensor
Large format
Cite
Citations (20)
A submillimeter continuum array instrument being built for the 15-m James Clerk Maxwell Telescope on Mauna Kea, Hawaii is described. The instrument contains 2 arrays, one of 91 pixels optimized for 438 microns and the second of 37 pixels optimized for 855 microns. Both are hexagonally close-packed, with each pixel having diffraction-limited angular resolution. Conical horns and single-moded waveguides are used to couple to the submillimeter beams, minimizing the bolometer background loading. A filter changing mechanism allows operations of the arrays at 350 and 750 microns. Single 'photometric' pixels are provided optimized for operation at 350, 600, 750, 1100, 1400 and 2000 microns. The instrument will have bolometers sensitive enough to reach the photon-noise sensitivity limit at both wavelengths, corresponding to an optical noise equivalent power (NEP) of 1.6 x 10 to the -16th WHz exp -1/2. This is achieved by cooling to 0.1 K, using a dilution refrigerator.
Noise-equivalent power
Transition edge sensor
Large format
Cite
Citations (15)
The next generation of far-infrared and submillimeter instruments require large arrays of detectors containing thousands of elements. These arrays will necessarily be multiplexed, and superconducting bolometer arrays are the most promising present prospect for these detectors. We discuss our current research into superconducting bolometer array technologies, which has recently resulted in the first multiplexed detections of submillimeter light and the first multiplexed astronomical observations. Prototype arrays containing 512 pixels are in production using the Pop-Up Detector (PUD) architecture, which can be extended easily to 1000 pixel arrays. Planar arrays of close-packed bolometers are being developed for the GBT and for future space missions. For certain applications, such as a slewed far-infrared sky survey, feedhorn-coupling of a large sparsely-filled array of bolometers is desirable, and is being developed using photolithographic feedhorn arrays. Individual detectors have achieved a Noise Equivalent Power (NEP) of ~10-17 W/√Hz at 300mK, but several orders of magnitude improvement are required and can be reached with existing technology. The testing of such ultralow-background detectors will prove difficult, as this requires optical loading of below 1fW. Antenna-coupled bolometer designs have advantages for large format array designs at low powers due to their mode selectivity. We also present a design and preliminary results for an enhanced-dynamic-range transition edge sensor suitable for broadband ultralow-background detectors.
Transition edge sensor
Large format
Noise-equivalent power
Cite
Citations (6)
SCUBA-2 is a state of the art 10,000 pixel submillimeter camera installed and being commissioned at the James Clerk Maxwell Telescope (JCMT) providing wide-field simultaneous imaging at wavelengths of 450 and 850 microns. At each wavelength there are four 32 by 40 sub-arrays of superconducting Transition Edge Sensor (TES) bolometers, each packaged with inline SQUID multiplexed readout and amplifier. In this paper we present the results of characterising individual 1280 bolometer science grade sub-arrays, both in a dedicated 50mk dilution refrigerator test facility and in the instrument installed at the JCMT.
Transition edge sensor
Large format
Cite
Citations (13)
SCUBA-2 is a revolutionary 10,000 pixel wide-field submillimetre camera, recently commissioned and now operational at the James Clerk Maxwell Telescope (JCMT). Twin focal planes each consist of four 32 by 40 sub-arrays of superconducting Transition Edge Sensor (TES) bolometers, the largest combined low temperature bolometer arrays in operation, to provide simultaneous imaging at wavelengths of 450 and 850 microns. SCUBA-2 was designed to map large areas of sky more than 100 times faster than the original ground breaking SCUBA instrument and has achieved this goal. In this paper we describe the performance of the instrument and present results of characterising the eight science grade TES bolometer arrays. We discuss the steps taken to optimise the setup of the TES arrays to maximise mapping speed and show how critical changes to the sub-array module thermal design, the introduction of independent focal plane and 1K temperature control and enhancements to the cryogenics have combined to significantly improve the overall performance of the instrument.
Large format
Transition edge sensor
First light
Field of view
Aperture (computer memory)
Cite
Citations (8)
We have been developing an architecture for producing large format, two dimensional arrays of close-packed bolometers, which will enable submillimeter cameras and spectrometers to obtain images and spectra orders of magnitude faster than present instruments. The low backgrounds achieved in these instruments require very sensitive detectors with NEPs of order 5 x 10(exp -18) W/square root of Hz. Superconducting transition edge sensor bolometers can be close-packed using the Pop-up Detector (PUD) format, and SQUID multiplexers operating at the detector base temperature can be intimately coupled to them. The array unit cell is 8 x 32 pixels, using 32- element detector and multiplexer components. We have fabricated an engineering model array with this technology which features a very compact, modular approach for large format arrays. We report on the production of the 32-element components for the arrays. Planned instruments using this array architecture include the Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory, the South Pole Imaging Fabry-Perot Interferometer (SPIFI) for the AST/RO observatory, the Millimeter Bolometer Camera for the Atacama Cosmology Telescope (MBC/ACT), and the Redshift (Z) Early Universe Spectrometer (ZEUS j.
Transition edge sensor
Large format
South Pole Telescope
Cite
Citations (0)