A Holography Receiver Design for the ALMA Submillimeter Antenna Surface Measurement

This paper describes the design and verification of the new Atacama large millimeter/submillimeter array antenna holography receiver hardware. The antenna deformation strongly depends on ambient temperature and Sun exposure. The purpose of the paper is to provide a holography receiver that can measure the diurnal and the seasonal antenna deformation. Key features of the holography receiver are an athermal endoskeleton structure, an external photonic local oscillator, a reduced number of high-frequency analog parts, and the introduction of a highly digitized processing system. The measured root mean square surface error is better than 4.4 μm, the repeatability is better than 2 μm, and the accuracy comparison result with the mechanical panel adjuster (screw mechanism) is better than 2.4 μm. We measured the daytime antenna deformation. The result of the daytime antenna deformation measurement we conducted shows that the surface panel inside the deformation is about 3 μm during the daytime.