ALMA band 1 optics (35-50 GHz): tolerance analysis, effect of cryostat infrared filters and cold beam measurements
Author
dc.contributor.author
González, A.
Author
dc.contributor.author
Tapia, V.
Author
dc.contributor.author
Finger Camus, Ricardo
Author
dc.contributor.author
Huang, C. D.
Author
dc.contributor.author
Asayama, S.
Author
dc.contributor.author
Huang, Y. D.
Admission date
dc.date.accessioned
2018-07-09T14:34:46Z
Available date
dc.date.available
2018-07-09T14:34:46Z
Publication date
dc.date.issued
2017
Cita de ítem
dc.identifier.citation
J Infrared Milli Terahz Waves, (2017) 38:1215–1231
es_ES
Identifier
dc.identifier.other
10.1007/s10762-017-0414-x
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/149638
Abstract
dc.description.abstract
The Atacama Large Millimeter/Sub-millimeter Array (ALMA) is currently the largest (sub-)mm wave telescope in the world and will be used for astronomical observations in all atmospheric windows from 35 to 950 GHz when completed. The ALMA band 1 (35-50 GHz) receiver will be used for the longest wavelength observations with ALMA. Because of the longer wavelength, the size of optics and waveguide components will be larger than for other ALMA bands. In addition, all components will be placed inside the ALMA cryostat in each antenna, which will impose severe mechanical constraints on the size and position of receiver optics components. Due to these constraints, the designs of the corrugated feed horn and lens optics are highly optimized to comply with the stringent ALMA optical requirements. In this paper, we perform several tolerance analyses to check the impact of fabrication errors in such an optimized design. Secondly, we analyze the effects of operating this optics inside the ALMA cryostat, in particular the effects of having the cryostat IR filters placed next to the band 1 feed horn aperture, with the consequent near-field effects. Finally, we report on beam measurements performed on the first three ALMA band 1 receivers inside test cryostats, which satisfy ALMA specifications. In these measurements, we can clearly observe the effects of fabrication tolerances and IR filter effects on prototype receiver performance.