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This paper reports the latest design and the associated fabrication technology of the Mk II prototype infrared (IR) detector for the two 5120 pixel SCUBA-2 (submillimetre common user bolometer arry) instruments, which are to be mounted on the James Clerk Maxwell telescope (JCMT) in Hawaii. Progress is described on the design and the technology modules being developed for the new detector, which is based upon silicon micromachining. The two arrays of transition edge sensors (TES) are used to detect incoming radiation with wavelengths of 450 and 850 μ respectively and as the SCUBA-2 detector operates at about 100 mK, it consequently involves integration with low-temperature electronics and careful design of the associated interconnect. A key aspect of the connection between the TES detector and readout electronics is the use of indium flip-chip bumps, which become superconducting at cryogenic temperatures. The integration of nanoscale membranes and transition edge sensors together with microsystem technology enables SCUBA-2 to have of the order of 10 -17W (1 Hz bandwidth) sensitivity to incoming radiation.

SCUBA-2 is an innovative 10000 pixel bolometer camera operating at submillimetre wavelengths on the James Clerk Maxwell Telescope (JCMT). The camera has the capability to carry out wide-field surveys to unprecedented depths, addressing key questions relating to the origins of galaxies, stars and planets. With two imaging arrays working simultaneously in the atmospheric windows at 450 and 850 microns, the vast increase in pixel count means that SCUBA-2 maps the sky 100-150 times faster than the previous SCUBA instrument. In this paper we present an overview of the instrument, discuss the physical characteristics of the superconducting detector arrays, outline the observing modes and data acquisition, and present the early performance figures on the telescope. We also showcase the capabilities of the instrument via some early examples of the science SCUBA-2 has already undertaken. In February 2012, SCUBA-2 began a series of unique legacy surveys for the JCMT community. These surveys will take 2.5 years and the results are already providing complementary data to the shorter wavelength, shallower, larger-area surveys from Herschel. The SCUBA-2 surveys will also provide a wealth of information for further study with new facilities such as ALMA, and future telescopes such as CCAT and SPICA., 23 pages, 20 figures, 3 tables. Accepted by MNRAS

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.

SCUBA-2 is a 10,000 pixel wide field sub-millimeter camera which started science observing on James Clerk Maxwell Telescope (JCMT) in the spring of 2010. We present the results of characterising individual 1280 bolometer science grade sub-arrays, as well as experience from operating the instrument.

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.

SCUBA-2 is a new wide-field submillimeter continuum instrument being commissioned on the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. SCUBA-2 uses large-scale arrays of superconducting bolometers with SQUID- (superconducting quantum interference device) based multiplexing and amplification. The sensitivity of the devices that compose the detector arrays to magnetic fields is such that magnetic shielding, consisting of superconducting and high-permeability materials, was fitted to the detector enclosure at 1 K to reduce the magnetic field strength at the focal plane. This paper describes the design and construction of the cryogenic shielding, and presents verification measurements. The shielding performance was found to meet the instrument requirements, and compared well to the modelled results.

SCUBA-2 is a new wide-field submillimeter continuum instrument being commissioned on the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. SCUBA-2 images simultaneously at 450 and 850 μm using large-scale arrays of superconducting bolometers, with over five thousand pixels at each wavelength. The arrays are cooled to less than 100 mK by the mixing chamber of a dilution refrigerator (DR), with a radiation shield at a nominal temperature of 1 K cooled by the DR still. The DR is a "dry" system, using a pulse tube cooler for precooling of the circulating helium in place of a liquid helium bath. This paper presents key performance data for the DR.

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 10 000 pixels, it will provide a revolutionary improvement in sensitivity and mapping speed. We present results of the first tests on a prototype 1280 pixel 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 120 mK. 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 17 WH Z 0.5 , within the requirements for SCUBA-2. The construction of the testbed used to carry out these measurements is also described. © 2007 American Institute of Physics. DOI: 10.1063/1.2436839

SCUBA-2 is an innovative 10,000 pixel submillimeter camera due to be delivered to the James Clerk Maxwell Telescope in late 2006. The camera is expected to revolutionize submillimeter astronomy in terms of the ability to carry out wide-field surveys to unprecedented depths addressing key questions relating to the origins of galaxies, stars and planets. This paper presents an update on the project with particular emphasis on the laboratory commissioning of the instrument. The assembly and integration will be described as well as the measured thermal performance of the instrument. A summary of the performance results will be presented from the TES bolometer arrays, which come complete with in-focal plane SQUID amplifiers and multiplexed readouts, and are cooled to 100mK by a liquid cryogen-free dilution refrigerator. Considerable emphasis has also been placed on the operating modes of the instrument and the common-user aspect of the user interface and data reduction pipeline. These areas will also be described in the paper., 15 pages; in Proceedings of Millimeter and Submillimeter Detectors and Instrumentation, SPIE, in press

We present the results of characterization measurements on a 1280 pixel superconducting bolometer array designed for operation at wavelengths around 450 μm. The array is a prototype for the sub-arrays which will form the focal plane for the SCUBA-2 sub-mm camera, being built for the James Clerk Maxwell Telescope (JCMT) in Hawaii. With over 10 000 pixels in total, it will provide a huge improvement in both sensitivity and mapping speed over existing instruments. The array consists of molybdenum-copper bi-layer TES (transition edge sensor) pixels, bonded to a multiplexer. The detectors operate at a temperature of approximately 175 mK, and require a heat sink at a temperature of approximately 60 mK. In contrast to previous TES arrays, the multiplexing elements are located beneath each pixel (an "in-focal plane" configuration). We present the results of electrical and optical measurements, and show that the optical NEP (noise equivalent power) is less than 1.4 × 10-16 W Hz-0.5 and thus within the goal of 1.5 × 10-16 W Hz-0.5.

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.

The SCUBA-2 instrument is a new wide field submillimeter imager currently being designed for the James Clerk Maxwell telescope on Mauna Kea in Hawaii. The instrument will observe simultaneously in the 450 and 850 micron bands and has a field of view of approximately 50 square arcminutes. To meet the performance requirements the detectors require a heat sink at a temperature of 50 mK or lower, and must be surrounded by an enclosure at a temperature of 1.1 K or below. Cooling is provided by the mixing chamber and still of a cryogen-free dilution refrigerator (DR), via thermal links of the order of a metre in length. A challenging set of requirements result from the need for a small temperature drop between the detectors and the refrigerator insert despite the large distance between them, the need to provide flexibility in the links to allow for movement during thermal contraction, and the need to allow for the detectors to be removed from the cryostat. Further, the arrays require a mounting structure which provides rigid mechanical support from the 1-K stage yet causes a very small heat input to millikelvin stage. This paper describes the design which has been evolved to meet these difficult (and often conflicting) requirements.

The SCUBA-2 instrument is a new wide-field imager under development for the James Clerk Maxwell Telescope on Mauna Kea in Hawaii and due to be operational in 2006. The instrument has two separate focal planes and is designed to observe simultaneously at wavelengths of 450 and 850μm. The instrument cryostat will weigh around 2500kg and has a volume of approximately 2.4x1.8x2.0m. The two detector arrays are operated at ~100mK and are surrounded by a cold enclosure at ~1K. Both the arrays and cold enclosure are cooled by a novel, liquid cryogen-free dilution refrigerator. To reduce the thermal background on the arrays to a minimum the main optics structure, weighing in excess of 450kg, must be cooled to less than 15K. A pair of low vibration pulse tube coolers are used to cool this structure and a radiation shield at ~60K. This paper describes the cryo-mechanical design of SCUBA-2 and discusses some of the issues and techniques needed to both cool the instrument within a reasonable timescale, and operate it in the required temperature regime

SCUBA-2, which replaces the Submillimetre Common User Bolometer Array (SCUBA) (Mon. Not. R. Astron. Soc. 303 (1999) 659) on the James Clerk Maxwell telescope in 2006, will be the first CCD-like array for submillimeter astronomy. Unlike previous detectors which have used discrete bolometers, SCUBA-2 has two DC-coupled, monolithic, filled arrays with a total of 10,000 bolometers. It will offer simultaneous imaging of an 8A—8 arcmin field of view at wavelengths of 850 and 450 I¼m. SCUBA-2 is expected to have a huge impact on the study of galaxy formation and evolution in the early Universe as well as star and planet formation in our own Galaxy. Mapping the sky to the same S/N up to 1000 times faster than SCUBA, it will also act as a pathfinder for the new submillimetre interferometers such as ALMA. SCUBA-2's absorber-coupled pixels use superconducting transition edge sensors (Ph.D. Thesis, Stanford, 1995) operating at 120 mK for photon noise limited performance. The monolithic silicon detector arrays are deep-etched by the Bosch process to isolate the pixels on silicon nitride membranes (Nucl. Instr. and Meth. A, these proceedings). Electrical connections are made through indium bump bonds to a backplane that incorporates a SQUID time-domain multiplexer. We describe the key technologies that make SCUBA-2 possible and give an update on the considerable progress in the detector development and instrument design that has taken place over the last 2 years

Spectral Energy Distributions (SEDs) covering the 50 - 190 µm range were obtained for a sample of Young Stellar Objects (YSOs) observed by the Infrared Space Observatory (ISO) and representing different stages of protostellar evolution. The ISO observations were complemented with IRAS data and with submillimetre observations done with the James Clerk Maxwell Telescope (JCMT). Data obtained with the single bolometer UKT14 were used together with 450 and 850 µm imaging data from SCUBA. The continuum observations were modelled with a phenomenological model in order to characterize the circumstellar environment of the objects. In this paper we show the results for IC1396N, one of the Class I sources observed by us.