NASA Scientific and Technical Aerospace Reports

mosaic imaging technique will be especially valuable for far IR and submillimeter interferometric space observatories such
as the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure
(SPECS). SPIRIT and SPECS will be designed to provide sensitive, high angular resolution observations of fields several
arcminutes in diameter, and views of the universe complementary to those provided by HST, NGST, and ALMA.
Author
Interferometers; Image Analysis; Mosaics; Optical Equipment; Imaging Techniques
20040074279 NASA Goddard Space Flight Center, Greenbelt, MD, USA
First Astronomical Use of Multiplexed Transition Edge Sensor Bolometers
Staguhn, J. G.; Ames, T. A.; Benford, D. J.; Chervenak, J. A.; Grossman, E. N.; Irwin, K. D.; Khan, S. A.; Maffei, B.; Moseley,
S. H.; Pajot, F., et al.; New Concepts for Far-Infrared and Submillimeter Space Astronomy; April 2004, pp. 374-377; In
English; See also 20040074260; No Copyright; Avail: CASI; A01, Hardcopy
We present performance results based on the first astronomical use of multiplexed superconducting bolometers. The
Fabry-Perot Interferometer Bolometer Research Experiment (FIBRE) is a broadband submillimeter spectrometer that achieved
first light in June 2001 at the Caltech Submillimeter Observatory (CSO). FIBRE’s detectors are superconducting transition
edge sensor (TES) bolometers read out by a SQUID multiplexer. The Fabry-Perot uses a low resolution grating to order sort
the incoming light. A linear bolometer array consisting of 16 elements detects this dispersed light, capturing 5 orders
simultaneously from one position on the sky. With tuning of the Fabry-Perot over one free spectral range, a spectrum covering
Delta lambda/lambda = 1/7 at a resolution of delta lambda/lambda approx. 1/1200 can be acquired. This spectral resolution
is sufficient to resolve Doppler-broadened line emission from external galaxies. FIBRE operates in the 350 m and 450 m
bands. These bands cover line emission from the important star formation tracers neutral carbon (CI) and carbon monoxide
(CO). We have verified that the multiplexed bolometers are photon noise limited even with the low power present in moderate
resolution spectrometry.
Author
Bolometers; Multiplexing; Fabry-Perot Interferometers; Spectrometers
20040074282 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Dual Transition Edge Sensor Bolometer for Enhanced Dynamic Range
Chervenak, J. A.; Benford, D. J.; Moseley, S. H.; Irwin, K. D.; New Concepts for Far-Infrared and Submillimeter Space
Astronomy; April 2004, pp. 378-381; In English; See also 20040074260; No Copyright; Avail: CASI; A01, Hardcopy
Broadband surveys at the millimeter and submillimeter wavelengths will require bolometers that can reach new limits of
sensitivity and also operate under high background conditions. To address this need, we present results on a dual transition
edge sensor (TES) device with two operating modes: one for low background, ultrasensitive detection and one for high
background, enhanced dynamic range detection. The device consists of a detector element with two transition temperatures
(T(sub c)) of 0.25 and 0.51 K located on the same micromachined, thermally isolated membrane structure. It can be biased
on either transition, and features phonon-limited noise performance at the lower T(sub c). We measure noise performance on
the lower transition 7 x 10(exp -18) W/rt(Hz) and the bias power on the upper transition of 12.5 pW, giving a factor of 10
enhancement of the dynamic range for the device. We discuss the biasable range of this type of device and present a design
concept to optimize utility of the device.
Author
Bolometers; Dynamic Range; Bias; Superconducting Devices
20040074283 NASA Goddard Space Flight Center, Greenbelt, MD, USA
TES Detector Noise Limited Readout Using SQUID Multiplexers
Staguhn, J. G.; Benford, D. J.; Chervenak, J. A.; Khan, S. A.; Moseley, S. H.; Shafer, R. A.; Deiker, S.; Grossman, E. N.;
Hilton, G. C.; Irwin, K. D., et al.; New Concepts for Far-Infrared and Submillimeter Space Astronomy; April 2004,
pp. 370-373; In English; See also 20040074260; No Copyright; Avail: CASI; A01, Hardcopy
The availability of superconducting Transition Edge Sensors (TES) with large numbers of individual detector pixels
requires multiplexers for efficient readout. The use of multiplexers reduces the number of wires needed between the cryogenic
electronics and the room temperature electronics and cuts the number of required cryogenic amplifiers. We are using an 8
channel SQUID multiplexer to read out one-dimensional TES arrays which are used for submillimeter astronomical
observations. We present results from test measurements which show that the low noise level of the SQUID multiplexers
allows accurate measurements of the TES Johnson noise, and that in operation, the readout noise is dominated by the detector
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