Chapter 14 System Component Descriptions 155
Note: In gated operation, the green TRIG LED indicator flashes each time the
PI-MAX is triggered. In early units, however, the light may not flash with very short
gate times. The exact gate width at which this occurs varies from unit to unit but
typically this occurs at ~15 ns. This trigger detection aberration has no affect
whatsoever on the unit’s ability to make measurements with narrow gate widths. The
PI-MAX continues to gate normally and data acquisition continues to take place in
the usual manner.
Note that actual triggering can still be readily determined by either of two methods.
First, the Timing Generator, whether a PTG or a DG535, has its own Trigger LED
indicator. As long as triggering continues to be indicated at the Timing Generator, the
user can be reasonably confidant that the PI-MAX is triggering properly. Second, the
signal at the PI-MAX Monitor output can be observed with a fast oscilloscope.
Although the Monitor signal won’t be able to make the full logic level at the shortest
attainable gate times, its presence can be easily verified, indicating that proper
triggering is taking place.
Fan: Ventilation fan that runs continuously to remove heat generated by the
thermoelectric cooler and the electronics. Air is drawn into the camera through the
side ventilation slots, picks up the heat from the electronics and the cooler, and is
then exhausted through the back panel grill.
Thermoelectric Cooler: The thermoelectric (TE) cooler is mounted to the heat removal
block. With air-cooling alone, at an ambient temperature of 25C, temperature lock at -
20 will generally occur within ten to twenty minutes. Note that the exact cooling
performance is a function of the CCD array installed. Also, if the lab is particularly
warm, achieving temperature lock might take longer or not occur at all.
ST-133 Controller
Electronics: The ST-133 controller is a compact, high performance CCD Camera
Controller for operation with Princeton Instruments brand
*
cameras. Designed for high
speed and high performance image acquisition, the ST-133 offers data transfer at speeds
up to 5 megapixel per second and standard video output for focusing and alignment. A
variety of A/D converters are available to meet different speed and resolution
requirements.
In addition to containing the power supply, the controller contains the analog and digital
electronics, scan control and exposure timing hardware, and controller I/O connectors, all
mounted on user-accessible plug-in modules. This highly modularized design gives
flexibility and allows for convenient servicing.
*
The ST-133 controller must be factory configured for operation with an LN detector. For this
reason, a controller purchased for operation with an LN detector can only be used with an LN
detector. Similarly, a controller purchased for operation with a TE detector cannot be used with
an LN detector.
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