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Assembly of a cryogenically-cooled Phased Array Feed, or cryoPAF -- a next generation version of
the receivers deployed on the ASKAP telescope -- is nearing completion.
A $1.15M LIEF grant from the Australian Research Council has supported the $3M project
to build the cryoPAF for
Murriyang, the Parkes 64m radio telescope.
The cryoPAF will be cooled to -243 degrees C to reduce 'noise' in its electrical circuits,
enhancing the ability to detect weak radio signals from the cosmos over a wide field of view,
at frequencies from 700 MHz to 1.9 GHz.
The cryoPAF is sometimes referred to as the "rocket PAF" as, rather than the
flat receiver plane used in the ASKAP PAFs, the individual dipole elements are
formed by tapered three-dimensional structures
(
visible in this image!).
The image above shows the underside of the receiver, with 26 modules used to
amplify the radio signals. Each module handles 8 "rockets", for a total of 208
PAF elements, which combine to form 196 PAF signals -- 98 in each of two
orthogonal polarisations
The solid plate at the front (and its counterpart at the opposite side) are where
the cryodynes connect to cool the enclosed volume to about 30 degrees above absolute zero.
The entire package is mounted within the (toothed) slewing ring, which enables the receiver to
be rotated as the telescope tracks in azimuth and elevation, so that
the PAF maintains the same orientation with respect to the sky.
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