My reasearch is focused on the One Centimetre Receiver Array Prototype (OCRA-p) a two beam receiver system designed as a proof of concept for the full OCRA which may ultimately consist of up to a 100 element horn array mounted at the secondary focus of the 32m radio telescope at the Torun Centre for Astrophysics in Poland. OCRA will operate at 1cm wavelength (30GHz) and should have a total bandwidth of 10GHz.
The OCRA-p receiver has been developed and built at Jodrell Bank Observatory. It is based on the 30GHz and 44GHz receivers built for the Low Frequency Instrument (LFI) on the PLANCK satellite and has no heterodyne stages; both the amplification and detection are carried out at 30GHz.
During the summer of 2002, I helped test OCRA-p on the bench in the laboratory and on the 30m Darnhall telescope which is part of the MERLIN network. In December 2002 it was shipped to Torun in Poland where it was tested again in the lab. It was finally mounted on the 32m telescope during the start of January 2003 and "first light" (the first proper observation) was shortly afterwards.
Atmospheric water vapour is well within the Fresnel diffraction region of the telescope when operating at 1cm. I have produced a short movie of how the diffraction pattern changes with distance (50m to 36000m) from the 32m aperture.
OCRA will hopefully be used in blind SZ surveys.
