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

• Published in: Journal of cosmology and astroparticle physics 2022-04, Vol.2022 (4), p.40
• Main Authors: 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, E., Marnieros, S., O'Sullivan, C., Passerini, A., Pezzotta, F., Piat, M., Torchinsky, S.A., Viganò, D., Voisin, F., Ade, P., Arnaldi, L.H., Auguste, D., Aumont, J., Banfi, S., Bélier, B., Bergé, L., Bersanelli, M., Bigot-Sazy, M.-A., Bonis, J., Bunn, E., Chanial, P., Chapron, C., Charlassier, R., Cobos Cerutti, A.C., Columbro, F., De Gasperis, G., De Leo, M., Dheilly, S., Duca, C., Dumoulin, L., 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., Hampel, M.R., Henrot-Versillé, S., Incardona, F., Jules, E., Kaplan, J., Kristukat, C., Lamagna, L., Loucatos, S., Louis, T., Mattei, A., May, A., Mele, L., Montier, L., Mousset, L., Mundo, L.M., Murphy, J.A., Nati, F., Olivieri, E., Pajot, F., Pastoriza, H., Pelosi, A., Perbost, C., Perciballi, M., Piccirillo, L., Pisano, G., Platino, M., Polenta, G., Prêle, D., Puddu, R., Rambaud, D., Ringegni, P., Romero, G.E., Schillaci, A., Scóccola, C.G., Scully, S., Spinelli, S., Stankowiak, G., Stolpovskiy, M., Timbie, P., Tucker, G., Vittorio, N., Wicek, F., Wright, M.
• Format: Article
• Language: English
• Subjects: Aluminum; Calibration; Chemical etching; CMBR detectors; CMBR experiments; CMBR polarisation; Cosmology; Frequency ranges; gravitational waves and CMBR polarization; Horns; Insertion loss; Instrumentation and Detectors; Physics; Self calibration; Switches; Waveguides
• ISSN: 1475-7516; 1475-7508; 1475-7516
• DOI: 10.1088/1475-7516/2022/04/040

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 (