256 Multiplexed PbS & PbSe Arrays FAQ (Frequently Asked Questions)
1. Is a chopper required?
No. The system integrates in the DC mode and has
dark current subtraction to remove the DC offset.
2. What is the maximum temperature the array assembly and board can be
exposed to either in operation or
during assembly process?
The system should not be stored or operated above
approximately 50°C.
3. Is lifetime data available?
No. Not yet, although our standard detector data
would apply to the array.
4. What are the power requirements for TEC?
+5V @ 1.5A max for the cooler and +12V @ 1A max for
everything else.
5. What is the wavelength sensitivity for both materials?
Answer: curves are on the website. Same as standard
materials at 0°C.
6. Does the array work for imaging applications?
No. The array uses an integrating multiplexer and
has high aspect ratio elements intended only for
spectroscopic applications.
7. What is the window material included in the array package?
AR coated Si.
8. What is the maximum input power (irradiance) to the detector? What will
happen if it is 'over exposed'?
Partial Answer? non-linearity is caused when so many
photons flood the detector active area that it actually heats up,
and can not recover completely during the dark portion of the chop. You
may find that using a lower bias voltage,
and faster chopping frequency is helpful, but you may also require some sort of
neutral density filter is required in
the optical path between the source of IR radiation, and the detector. Same as
with our other detectors.
9. How many bit resolution in A/D conversion system?
The multiplexer has an analog output. The interface
electronics board uses a true 14bit (all bits are significant)
A/D converter that operates at 100K samples/sec.
10. Can I operate the array at a colder temperature than 0C?
Yes. We can provide custom set points to around
-10°C. Colder temperatures will require more heatsinking.
11. Any limitations to the chopping Frequency?
Since this is a DC system (see #1) there is no chopper
required.