Speaker
Dr
Dave Walton
(Mullard Space Science Lab, University College London)
Description
Results are described from a high-stability multi-CCD focal plane
assembly developed by MSSL for ESA, using new large-format CCDs from
e2v technologies. Particular subjects of investigation are stability
at the 10e-4 to 10e-5 level and crosstalk between CCDs as well as
between nodes of each two-port CCD.
Space-based planetary-transit hunting and asteroseismology missions
such as ESA's Eddington and NASA's Kepler require large multi-CCD
focal planes in order to simultaneously observe a large number of
objects to improve the odds of finding habitable planets. A second
driving requirement is that the system must be extremely stable so
that false detections are not generated. This places significant
constraints (both in-orbit and for the ground-based tests described
here) on, for example, temperature stability and electronics
stability. Other significant requirements are wide dynamic range (16-
bit digitisation, using a CCLRC CCD signal processor ASIC) and a
moderately high readout rate of ~1.2Mpix/s per output chain
(Eddington has in total ~3 focal planes each with 12 output chains).
Although Eddington is currently not in ESA's approved mission list,
MSSL has received an ESA contract to develop a demonstration FPA
with realistic constraints on parameters such as performance (e.g.
stability, noise), mass, power, and component selection (radiation
hardness etc.). This work provides real world data for future ESA
studies. In addition, the demo-FPA electronics has been designed to
be compatible with the Gaia-RVS focal plane, another system which
requires multiple CCDs, low noise and stability. The demo-FPA is
populated with three e2v CCD42-C0s, a member of the CCD42 family
specifically developed for Eddington under ESA contract.
The demo-FPA system is described here, including the new high-
accuracy temperature-control system and the high-throughput
spacewire digital data links. Results are described from the tests
performed on the demo-FPA, specifically stability, noise and both
inter- and intra-CCD crosstalk. Finally, the application of the
system to the Gaia-RVS focal plane (which uses e2v electron-
multiplying low-light-level CCDs) is described.
Primary author
Dr
Dave Walton
(Mullard Space Science Lab, University College London)
