A compact, modular superconducting bolometer array package (original) (raw)
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A Compact, Modular Package for Superconducting Bolometer Arrays
As bolometer arra ys g row to ever-larger forma ts, packaging becomes a more critical engineering issue. We ha ve designed a detector package to house a superconducting bolometer a rray, SQUID multiplexe rs, bias and filtering circuitry, an d ele ctrical connectors. Th e p ackage in cludes an optical fi lter, magnetic shield ing, and has well-def ined ther mal and mechanical interfaces. An early version of this package has been used successfully in the GISMO 2mm camera, a 128-pixel camera operat ing at a base temperature of 270mK. A m ore advanced package perm its operation at lower temp eratures b y providing direct heat sinking to the SQUIDs and bias r esistors, which ge nerate the bulk of the dissipation in the pac kage. Standard elect rical con nectors p rovide re liable con tact while enabling quick installation a nd removal of the package. The design compensates for differing the rmal e xpansions, allo ws heat sinking o f the bolome ter ar ray, and fe atures magnetic shielding in critical areas. It will be sca led to 1280-pixel a rrays in the near future.
Characterization of a prototype SCUBA-2 1280-pixel submillimetre superconducting bolometer array
Millimeter and Submillimeter Detectors and Instrumentation for Astronomy III, 2006
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 requirement of 2.9 × 10 −16 W Hz −0.5 .
Design and fabrication of two-dimensional superconducting bolometer arrays
2003
We have been developing an architecture for producing large format, two-dimensional arrays of close-packed bolometers, which will enable far-infrared to millimeter wavelength (l=100 m-2 mm) 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 ranging from 10 -17 to 10 -19 W/ 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¥32 pixels, using 32element detector and multiplexer components. We have fabricated an engineering model array with this technology featuring 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).
Review of Scientific Instruments, 2007
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 ͑TES͒ 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 ϫ 10 −17 W HZ −0.5 , within the requirements for SCUBA-2. The construction of the testbed used to carry out these measurements is also described.
Characterising the SCUBA-2 superconducting bolometer arrays
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V, 2010
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.
The 350 Micrometer Wavelength Superconducting Bolometer Camera for APEX
2009
Since spring 2008, the Small Array Bolometer Camera (SABOCA) operates at APEX (Atacama Pathfinder Experiment), a 12 meter radio telescope on the high plateau Llano de Chajnantor in Chile's Atacama Desert. This instrument utilizes an array of 37 transition edge sensors to detect sub-millimeter radiation in a narrow band around 350µm wavelength, which fits the last useful atmospheric radio window on earth. The TES array is operated at a temperature of 300 mK, enabling a background-limited operation with a measured noise equivalent flux density of around 200 mJy/s 1/2 . SABOCA is the precursor of larger arrays, so it is already equipped with a SQUID time-domain multiplexer, which combines ten bolometer channels each to altogether 4 output channels. We show the configuration of the instrument and present the measured performance under real operating conditions. To our knowledge, this is the first operating superconducting bolometer camera for astronomy entirely conceived and constru...
Multiplexed readout of superconducting bolometers
2000
Studies of emission in the far-infrared and submillimeter from astrophysical sources require large arrays of detectors containing hundreds to thousands of elements. A multiplexed readout is necessary for practical implementation of such arrays, and can be developed using SQUIDs, such that, e.g., a 32×32 array of bolometers can be read out using ∼100 wires rather than the >2000 needed with a brute force expansion of existing arrays. These bolometer arrays are made by micromachining techniques, using superconducting transition edge sensors as the thermistors. We describe the development of this multiplexed superconducting bolometer array architecture as a step toward bringing about the first astronomically useful arrays of this design. This technology will be used in the SAFIRE instrument on SOFIA, and is a candidate for a wide variety of other spectroscopic and photometric instruments.
Characterising the SCUBA-2 superconducting bolometer arrays
SPIE Proceedings, 2010
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.
Design and fabrication of a 2D superconducting bolometer array for SAFIRE
2003
The Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory will employ a largeformat, two-dimensional, close-packed bolometer array. SAFIRE is an imaging Fabry-Perot spectrometer operating at wavelengths between 100µm and 700µm. The array format is 16x32 pixels, using a 32-element multiplexer developed in part for this instrument. The low backgrounds achieved in spectroscopy require very sensitive detectors with NEPs of order 10 -19 W/√Hz. An architecture which permits 512 pixels to be placed adjacent to each other in an area the size of a postage stamp, integrate them with multiplexers, and provide all the necessary wiring interconnections is a complex proposition, but can be achieved. Superconducting detectors 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 result is a compact array, easily scalable to kilopixel arrays. We describe the PUD architecture, superconducting transition edge sensor bolometers we have manufactured and tested using the PUD architecture, and the electronics of SQUID multiplexed readouts. We show the design and assembly of the mechanical model of a 512-element bolometer array.
On-Chip Integrated SQUID Readout for Superconducting Bolometers
IEEE Transactions on Appiled Superconductivity, 2005
We present the first steps toward a 288 pixel sub-millimeter wavelength bolometer camera. We have used bolometers of the transition edge type, choosing a thermometer made of a proximity bilayer of Mo and the alloy Au/Pd with a designed transition temperature of about 500 mK. We have adapted our well-developed niobium based technology for SQUID manufacturing in order to be able to fabricate the current sensor and the bolometer on a common substrate. The function of both devices was successfully tested at the operating temperature of 300 mK.