Instrument performance of GISMO, a 2 millimeter TES bolometer camera used at the IRAM 30 m Telescope

Abstract

We have developed key technologies to enable highly versatile, kilopixel bolometer arrays for infrared through millimeter wavelengths. Our latest array architecture is based on our Backshort Under Grid (BUG) design, which is specifically targeted at producing kilopixel-size arrays for future ground-based, suborbital and space-based X-ray and far-infrared through millimeter cameras and spectrometers.In November of 2007, we demonstrated a monolithic 8x16 BUG bolometer array with 2 mm-pitch detectors for astronomical observations using our 2 mm wavelength camera GISMO (the Goddard IRAM Superconducting 2 Millimeter Observer) at the IRAM 30 m telescope in Spain. The 2 mm spectral range provides a unique terrestrial window enabling ground-based observations of the earliest active dusty galaxies in the universe and thereby allowing a better constraint on the star formation rate in these objects. We present preliminary results from our observing run with the first fielded BUG bolometer array and discuss the performance of the instrument.

Design and Expected Performance of GISMO-2, a Two Color Millimeter Camera for the IRAM 30 m Telescope

“…Cooling power from 300 to 3 K is provided by a closed-cycle Cryomech PT415 cryo-cooler. A combination of 4 He and 3 He Fig. 2 A hybridized 1 mm, 32×40 pixel prototype BUG array with integrated backshort and bump-bonded to a 2-dimensional SQUID multiplexer from NIST/Boulder (Color figure online) Fig.…”

“…2 A hybridized 1 mm, 32×40 pixel prototype BUG array with integrated backshort and bump-bonded to a 2-dimensional SQUID multiplexer from NIST/Boulder (Color figure online) Fig. 3 The GISMO-2 fridge consists of a 3 He/ 4 He dilution refrigerator, which is buffered by a 4 He/ 3 He adsorption pre-cooler (Color figure online) evaporation coolers, produced by Chase Research Cryogenics, then pre-cool a dilution refrigerator (Fig. 3) which provides a base temperature of 50 mK for the detector arrays with a hold time of close to 24 h.…”

“…[1]). Our team has a long legacy in building and using TES based instrumentation, having successfully fielded FIBRE, the first TES based instrument with multiplexed readout [2], and recently the Goddard-IRAM Superconducting 2 mm Observer GISMO [3], which is available for astronomical observations (e.g. [4,5]) at the IRAM 30 m telescope in Spain through the regular IRAM call for proposals.…”

The SPICA-SAFARI Detector System: TES Detector Arrays With Frequency-Division Multiplexed SQUID Readout

“…SiN-suspended TES detectors are used in sub-mm and mm-wave detectors for many ground-based telescopes [13]- [16]. However, the move to a space-based observatory with a cryogenically cooled telescope reduces the background load on the detectors by orders of magnitude.…”