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The FTS Air-Jet Crystal
Cooling System consists of: |
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The AD-80X
air dryer, which includes the air inlet pressure control and gauge, an
oil and particle filter, and a heatless regenerative dryer to reduce the
air's dew point to -100° C.
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The XR-85-1
mechanical refrigeration system, which delivers a stream of air whose
temperature is controllable between -85° and +100° C. The air passes
through a flexible line to a heater and nozzle assembly, which is
mounted near the sample. A thermocouple in the nozzle is connected to a
digital indicator/controller, which continuously displays the
temperature to the nearest 0.1° C.
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The TC-44,
a fast-cycling controller, which controls the power to the heater to
maintain the nozzle temperature at the set point. The controller
incorporates anticipation circuitry to prevent overshoot and automatic
reset to provide control to within +/- 0.1° C of the set point. The
TC-44 also provides a -5 V to +5 V analog output that may be used to
monitor temperature on a chart recorder or other logging device.
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These components are all mounted on a cart, so that the entire system
may be easily wheeled into and out of a hutch.
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Attach the nozzle to the
optical table, pointing along the spindle axis. For maximum cooling, the
opening of the nozzle should be within 1-2 cm. of the sample (crystal)
location.
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Attach a compressed air hose
to the quick-disconnect connection located at the left side of the
AD-80X air dryer.
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Turn on the air dryer and
adjust the outlet pressure to 60 psi, if necessary.
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Turn on the refrigeration
unit and the temperature controller.
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Adjust the cold air valve to
about 15 psi; open the warm air valve (located over the holding tank) by
1/4 to 1/2 turn. |
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Manual set-point: |
Release the REMOTE button
(button is up).
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Press and hold the DISPLAY
button. Adjust the set-point knob to the desired temperature (the tested
temperature range is -50° to +30° C). Release the DISPLAY button.
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Remote set-point: |
Engage the
REMOTE button (button is depressed).
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Press one of
the four remote set-point buttons.
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Press and hold
the DISPLAY button. Adjust the set-point pot to the desired temperature
(in the -50° to +30° C range) with a small screwdriver. Release the
DISPLAY button.
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Repeat steps 2
- 3 for other remote set-points.
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Note - it will take
approximately 20 minutes for initial temperature pull-down |
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Turn off the refrigeration
unit and temperature controller.
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Let air continue to flow for
10 minutes. Then turn off the air dryer.
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Detach the nozzle from the
optical table; secure the nozzle on top of the FTS cart.
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Return to Contents |
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This page
was written by Joseph H. Navaie |
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