QUBIC VII: The feedhorn-switch system of the technological demonstrator

CAVALIERE, F.; MENNELLA, A.; ZANNONI, M.; BATTAGLIA, P.; BATTISTELLI, E.S.; DE BERNARDIS, P.; BURKE, D.; D'ALESSANDRO, G.; DE PETRIS, M.; FRANCESCHET, C.; GRANDSIRE, L.; HAMILTON, J.-CH.; MAFFEI, B.; MANZAN, B.; MARNIEROS, S.; MASI, S.; O'SULLIVAN, C.; PASSERINI, A.; PEZZOTTA, F.; PIAT, M.; TARTARI, A.; TORCHINSKY, S.A.; VIGANÒ, D.; VOISIN, F.; ADE, P.; ALBERRO, J.G.; ALMELA, A.; AMICO, G.; ARNALDI, L.H.; AUGUSTE, D.; AUMONT, J.; AZZONI, S.; BANFI, S.; BAÙ, A.; BÉLIER, B.; BENNETT, D.; BERGÉ, L.; BERNARD, J.-PH.; BERSANELLI, M.; BIGOT-SAZY, M.-A.; BONAPARTE, J.; BONIS, J.; BUNN, E.; BUZI, D.; CHANIAL, P.; CHAPRON, C.; CHARLASSIER, R.; COBOS CERUTTI, A.C.; COLUMBRO, F.; COPPOLECCHIA, A.; DE GASPERIS, G.; DE LEO, M.; DHEILLY, S.; DUCA, C.; DUMOULIN, L.; ETCHEGOYEN, A.; FASCISZEWSKI, A.; FERREYRO, L.P.; FRACCHIA, D.; GAMBOA LERENA, M.M.; GANGA, K.M.; GARCÍA, B.; GARCÍA REDONDO, M.E.; GASPARD, M.; GAYER, D.; GERVASI, M.; GIARD, M.; GILLES, V.; GIRAUD-HERAUD, Y.; GÓMEZ BERISSO, M.; GONZÁLEZ, M.; GRADZIEL, M.; HAMP

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

IOP PUBLISHING LTD

Año: 2022 vol. 2022

1475-7516

We present the design, manufacturing and performance of the horn-switch system developed for the technological demonstrator of QUBIC (the Q&U Bolometric Interferometer for Cosmology). This system consists of 64 back-to-back dual-band (150 GHz and 220 GHz) corrugated feed-horns interposed with mechanical switches used to select desired baselines during the instrument self-calibration. We manufactured the horns in aluminum platelets milled by photo-chemical etching and mechanically tightened with screws. The switches are based on steel blades that open and close the waveguide between the back-to-back horns and are operated by miniaturized electromagnets. The measured electromagnetic performance of the feedhorns agrees with simulations. In particular we obtained a return loss around -20 dB up to 230 GHz and beam patterns in agreement with single-mode simulations down to -30 dB. The switches for this prototype were designed and built for the 150 GHz band. In this frequency range we find return and insertion losses consistent with expectations (< -25 dB and ∼-0.1 dB, respectively) and an isolation larger than 70 dB. In this paper we also show the current development status of the feedhorn-switch system for the QUBIC full instrument, based on an array of 400 horn-switch assemblies.