NASA Scientific and Technical Aerospace Reports

noise. Multiplexers for large number of channels require a large bandwidth for the multiplexed readout signal. We discuss the
resulting implications for the noise performance of these multiplexers which will be used for the readout of two dimensional
TES arrays in next generation instruments.
Author
Sensors; Superconductivity; Submillimeter Waves; Readout; Noise Intensity
20040074285 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Least-Squares Self-Calibration of Imaging Array Data
Arendt, R. G.; Moseley, S. H.; Fixsen, D. J.; New Concepts for Far-Infrared and Submillimeter Space Astronomy; April 2004,
pp. 382-390; In English; See also 20040074260; No Copyright; Avail: CASI; A02, Hardcopy
When arrays are used to collect multiple appropriately-dithered images of the same region of sky, the resulting data set
can be calibrated using a least-squares minimization procedure that determines the optimal fit between the data and a model
of that data. The model parameters include the desired sky intensities as well as instrument parameters such as pixel-to-pixel
gains and offsets. The least-squares solution simultaneously provides the formal error estimates for the model parameters. With
a suitable observing strategy, the need for separate calibration observations is reduced or eliminated. We show examples of
this calibration technique applied to HST NICMOS observations of the Hubble Deep Fields and simulated SIRTF IRAC
observations.
Author
Calibrating; Imaging Techniques; Least Squares Method
20040074290 Max-Planck-Inst. fuer Extraterrestrische Physik, Garching, Germany
Integral Field Spectroscopy in the Far Infrared
Poglitsch, Albrecht; Geis, Norbert; Looney, Leslie; Raab, Walfried; New Concepts for Far-Infrared and Submillimeter Space
Astronomy; April 2004, pp. 301-308; In English; See also 20040074260; No Copyright; Avail: CASI; A02, Hardcopy
We are presently building far-infrared integral field spectrometers for Herschel (PACS) and SOFIA (FIFI LS). These have
become possible by: (1) the development of relatively large, low noise photoconductor arrays and their associated cryogenic
readout electronics and (2) a novel design for a reflective image slicer which - compared to equivalent designs in the visible
or near-infrared - leads to a very compact unit capable of handling the large etendue (A(Omega)) required in a diffraction
limited FIR system. In conjunction with a moderate size (30 cm x 8 cm) grating this concept allows for moderate resolution
(R approx. 2000), imaging spectroscopy perfectly suited for extragalactic astronomy. If we project the recent progress in
detector development (photoconductors and bolometers) in terms of number of pixels and sensitivity into the near future then
this instrument concept could be readily extended in two ways which could contribute significantly to the scientific success
of SAFIR: A line spectrometer with an instantaneous spectral coverage of a modest number of resolutions elements but a large
field of view would ideally complement the photometric imaging capabilities of the mission for objects that can be spatially
resolved. Applications could be spectral line maps of galaxies which would allow detailed diagnostics of phenomena like
sequential star formation, galaxy interaction, and nuclear activity. Complementary to this, a small field of view in combination
with very broad spectral coverage would be ideally suited for pointing-uncertainty tolerant spectroscopy, including
spectroscopic redshift determination, of galaxies in the early universe, with the goal to study their formation and evolution
(star formation and AGN formation).
Author
Spectroscopy; Far Infrared Radiation; Imaging Techniques
20040074291 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Progress Towards High-Sensitivity Arrays of Detectors of Sub-mm Radiation Using Superconducting Tunnel Junctions
with Integrated Radio Frequency Single-Electron Transistors
Stevenson, T. R.; Hsieh, W.-T.; Li, M. J.; Prober, D. E.; Rhee, K. W.; Schoelkopf, R. J.; Stahle, C. M.; Teufel, J.; Wollack,
E. J.; New Concepts for Far-Infrared and Submillimeter Space Astronomy; April 2004, pp. 349-358; In English; See also
20040074260
Contract(s)/Grant(s): NSG5-8589; No Copyright; Avail: CASI; A02, Hardcopy
For high resolution imaging and spectroscopy in the FIR and submillimeter, space observatories will demand sensitive,
fast, compact, low-power detector arrays with 104 pixels and sensitivity less than 10(exp -20) W/Hz(sup 0.5). Antennacoupled
superconducting tunnel junctions with integrated rf single-electron transistor readout amplifiers have the potential for
achieving this high level of sensitivity, and can take advantage of an rf multiplexing technique. The device consists of an
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