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An efficient phase-shifting scheme for bolometric additive interferometry
Charlassier R., Hamilton J.-C., Bréelle E., Ghribi A., Giraud-Héraud Y. et al
Astronomy and Astrophysics 497 (2009) 963-971 - http://hal.in2p3.fr/in2p3-00285456
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique
Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique
An efficient phase-shifting scheme for bolometric additive interferometry
R. Charlassier1, J.-C. Hamilton1, É. Bréelle1, A. Ghribi1, Y. Giraud-Héraud1, J. Kaplan1, M. Piat1, D. Prêle1
1 :  APC - UMR 7164 - AstroParticule et Cosmologie
http://www.apc.univ-paris7.fr/
CNRS : UMR7164 – IN2P3 – Observatoire de Paris – Université Paris VII - Paris Diderot – CEA : DSM/IRFU
APC - UMR 7164, Université Paris Diderot, 10 rue Alice Domon et Léonie Duquet, case postale 7020, F-75205 Paris Cedex 13
France
APC - Cosmologie et Gravitation
Context: Most upcoming CMB polarization experiments will use direct imaging to search for the primordial gravitational waves through the B-modes. Bolometric interferometry is an appealing alternative to direct imaging that combines the advantages of interferometry in terms of systematic effects handling and those of bolometric detectors in terms of sensitivity. Aims: We calculate the signal from a bolometric interferometer in order to investigate its sensitivity to the Stokes parameters paying particular attention to the choice of the phase-shifting scheme applied to the input channels in order to modulate the signal. Methods: The signal is expressed as a linear combination of the Stokes parameter visibilities whose coefficients are functions of the phase-shifts. Results: We show that the signal to noise ratio on the reconstructed visibilities can be maximized provided the fact that the phase-shifting scheme is chosen in a particular way called coherent summation of equivalent baselines. As a result, a bolometric interferometer is competitive with an imager having the same number of horns, but only if the coherent summation of equivalent baselines is performed. We confirm our calculations using a Monte-Carlo simulation. We also discuss the impact of the uncertainties on the relative calibration between bolometers and propose a way to avoid this systematic effect.

Articles dans des revues avec comité de lecture
2009
Astronomy and Astrophysics (Astron. Astrophys.)
Publisher EDP Sciences
ISSN 0004-6361 (eISSN : 1432-0756)
497
963-971

8 pages, 6 figures
Lien vers le texte intégral : 
http://fr.arXiv.org/abs/0806.0380