Murphy, J.A. and Peacocke, T. and Maffei, B. and McAuley, I. and Noviello, F. and Yurchenko, V. and Ade, P.A.R. and Savini, G. and Lamarre, J.-M. and Brossard, J. and Colgan, R. and Gleeson, E. and Lange, A.E. and Longval, Y. and Pisano, G. and Puget, J.-L. and Ristorcelli, I. and Sudiwala, R. and Wylde, R.J.
Multi-mode horn design and beam characteristics for
the Planck satellite.
Journal of Instrumentation, 5 (T04001).
The ESA Planck satellite has begun studying the anisotropies of the cosmic microwave
background radiation over the whole sky with unprecedented sensitivity and high angular resolution.
The High Frequency Instrument, HFI, on Planck is observing simultaneously in six bands in the range 100 GHz to 857 GHz. The inclusion of non-CMB bands allows for robust removal
of foreground sources from the data. This paper is concerned with the design, modeling and predicted
performances of the two highest frequency channels centered on 545 GHz and 857 GHz,
which use specialized multi-mode feedhorns, and are dedicated to observing these foregrounds.
Multi-mode systems have the advantage of increasing the throughput, and thus sensitivity, of the
detection assembly when diffraction limited resolution is not required. The horns are configured
in a back-to-back setup which transmits the signal through filters to a detector horn. The modeling
of the broadband beam patterns on the sky is shown to require careful analysis. Simulations of
the complex interactions of the horns is computationally challenging when the detector horn in the
relay system is included. The paper describes the approach to modeling these high frequency channels
and discusses how the optical requirements on the horn designs are met in terms of spillover,
edge taper, illumination of the telescope aperture and beam patterns on the sky.
||The definitive version of this article is available at doi:10.1088/1748-0221/5/04/T04001 . © 2010 IOP Publishing Ltd and SISSA
||Microwave Antennas; Space instrumentation; Optics; Waveguides; Planck Satellite;
||Science & Engineering > Experimental Physics
Dr. Anthony Murphy
||12 Dec 2012 16:32
|Journal or Publication Title:
||Journal of Instrumentation
||Institute of Physics
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