System Integration, Laboratory
and Field Work
In addition to the software for the Fast Cryogenic Array Spectrometer (FCAS),
I have worked on the instrument and its peripherals. The instrument
hardware consists of three modules: a vacuum/cryogenic/optical dewar,
a "telescope" rack, and an "observer's" rack. The observer's rack
contains a Sun computer which controls the whole affair and sits in the
observation room of an observatory when in use. The telescope rack
contains the equipment necessary to operate the dewar, and sits next to
the telescope when in use. The dewar attaches to the focal plane
of a telescope (it can adapt to many telescopes, such as the NASA IRTF
or Lowell 72-inch).
The two equipment racks are aircraft-certified, and are coupled by optical
fiber to eliminate signal degradation and radiation into the observatory
environment. These fibers carry control and signal information via
RS-232 serial protocol and custom protocols for the infrared array electronics.
I assembled the racks with all peripherals, made custom cables, and
built the fiber cable assembly, which consists of five active pairs with
optical modems at each end. I also constructed housings for this
equipment so that it could be rack-mounted. In addition, I configured
the UNIX controller with all custom and commercial software and security
precautions. Below are clickable images of the racks.
 |
 |
| racks with coiled fiber cable |
optical modem assembly on telescope rack |
Calibration lamps (Argon, Krypton, Xenon, and continuum) are used to
calibrate the instrument to known spectral features. Some of these
lamps are activated by an intelligent controller which requires a special
signal from the host computer in the observer's rack. The host computer
communicates with the telescope-rack-mounted intelligent controller via
fiber. I built a current-limited voltage source which is used to
generate this special signal for lamp activation. I also constructed
"through-hull" connections and cables for the calibration apparatus.
During two years of instrumentation development I have assembled and
disassembled the dewar many times; it is a complex operation which takes
at least two days. The work is performed in low-level clean room
conditions with electrostatic precautions.
I have also traveled with the instrument on field operations and am
accustomed to operating vacuum-cryogenic equipment and large optical telescopes.
|