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General view of the cryostat being pumped. Notice the berylium
window to allow characterization of the CCDs
with a X-ray source.
The CFH12K focal plane is ran by two SDSUII controllers
(designed
by Bob Leach). They are the boxes of both sides
of the cryostat.
The camera will be in a look-down configuration
at the CFHT prime
focus. Using the data acquisition system developed
at CFHT, 4 electrons
readout noise has been obtained on one test device
during 58 seconds
readouts (full mosaic). Both controllers will
be synchronyzed to
within 6 nanoseconds.
[Taken August 1998]
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This picture shows four MIT/LL CCDs (CCID20) ready to be mounted
on
the CFH12K focal plane. Notice the flexprint
that connects to a
miniature SUBD connector. Extensive use of flexprint
greatly reduces
the number of wires inside the cryostat (e.g.
the UH8K). Each device
is about 3.5 by 7 centimeters (2048x4096 15um
square pixels).
[Taken August 1998] |
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View of the focal plane with 4 CCDs. The CCDs mount on the cold
plate
which temperature is monitored and regulated.
Notice the short path
from the CCDs to the controllers. CCDs are not
aligned in regard of
each other: proper calibration will be required
on the sky to allow
proper astrometric calibration.
[Taken August 1998]
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General view of the filter wheel (top). This is big. The rectangle
window (the cryostat mount on that upper left
plate) is about 15
per 38 centimeters. The filter wheel can hold
4 filters at once.
Filter can be easily changed through the port
shown opened on the
lower right.
[Taken September 1998]
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This second picture shows the stack assembly of the unit: the
shutter is positionned between the filter wheel
and the cryostat.
Notice the teeth of the filter wheel, the design
is based on a
geneva mechanisms. A filter frame is shown on
the left.
[Taken September 1998]
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One of the two CCD controllers. Each controller contains
the following
set of boards from SDSU: one timing board, one
utility board, three
clocking boards (one per two CCD) and three clocking
boards also.
They all connect on a common backplane powered
by a power control
board. The cables coming out from the clocking
and video boards (three
sets) connect onto the three hermetic 128 pins
connectors that can
be seen on the right (after the connector, inside
the cryostat, all
connections are made through flexprints).
[Taken August 1998]
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