Bibcode
Hoyland, R.; Aguiar-González, M.; Génova-Santos, R.; Gómez-Reñasco, F.; López-Caraballo, C.; Rebolo, R.; Rubiño-Martín, J. A.; Sánchez-de la Rosa, V.; Vega-Moreno, A.; Viera-Curbelo, T.; Pelaez-Santos, A.; Vignaga, R.; Tramonte, D.; Poidevin, F.; Pérez-de-Taoro, M. R.; Martínez-Gonzalez, E.; Aja, B.; Artal, E.; Cagigas, J.; Cano-de-Diego, J. L.; Cuerno, E. M.; de-la-Fuente, L.; Pérez, A.; Ortiz, D.; Terán, J. V.; Villa, E.; Piccirillo, L.; Hobson, M.
Bibliographical reference
Proceedings of the SPIE, Volume 9153, id. 915332 17 pp. (2014).
Advertised on:
8
2014
Citations
2
Refereed citations
1
Description
The QUIJOTE TGI instrument is currently being assembled and tested at
the IAC in Spain. The TGI is a 31 pixel 26-36 GHz polarimeter array
designed to be mounted at the focus of the second QUIJOTE telescope.
This follows a first telescope and multi-frequency instrument that have
now been observing almost 2 years. The polarimeter design is based on
the QUIET polarimeter scheme but with the addition of an extra 90º
phase switch which allows for quasiinstantaneous complete QUI
measurements through each detector. The advantage of this solution is a
reduction in the systematics associated with differencing two
independent radiometer channels. The polarimeters are split into a cold
front end and a warm back end. The back end is a highly integrated
design by the engineers at DICOM. It is also sufficiently modular for
testing purposes. In this presentation the high quality wide band
components used in the optical design (also designed in DICOM) are
presented as well as the novel cryogenic modular design. Each
polarimeter chain is accessible individually and can be removed from the
cryostat and replaced without having to move the remaining pixels. The
optical components work over the complete Ka band showing excellent
performance. Results from the sub unit measurements are presented and
also a description of the novel calibration technique that allows for
bandpass measurement and polar alignment. Terrestrial Calibration for
this instrument is very important and will be carried out at three
points in the commissioning phase: in the laboratory, at the telescope
site and finally a reduced set of calibrations will be carried out on
the telescope before measurements of extraterrestrial sources begin. The
telescope pointing model is known to be more precise than the expected
calibration precision so no further significant error will be added
through the telescope optics. The integrated back-end components are
presented showing the overall arrangement for mounting on the cryostat.
Many of the microwave circuits are in-house designs with performances
that go beyond commercially available products.