Filter
Top Products
22 NTE/CCD Detector Manual Version 2.A
fluorescent overhead lamps have good calibration lines as well. If there are no
“line” sources available, it is possible to use a broad band source, such as
tungsten, for the alignment. If this is the case, use a wavelength setting of 0.0nm
for alignment purposes.
2.
With the Model SP300i properly connected to the controller, turn the power on
and wait for the spectrograph to initialize. Then set it to 435.8 nm if using a
mercury lamp or to 0.0 nm if using a broadband source.
Hint:
Overhead fluorescent lights produce a mercury spectrum. Use a white card
tilted at 45 degrees in front of the entrance slit to reflect overhead light into the
spectrograph. Select 435.833 as the spectral line.
3.
Set the Exposure Time of the array to a convenient value somewhere in the range
of 0.1 s to 1 s.
4.
Set the slit to 25 µm.
5.
Run the Detector in live mode and watch the display on the monitor.
Hint:
If using WinView/32 or WinSpec/32, select FOCUS with Freerun and
Safe Mode (asynchronous) timing selected. If using WinView or WinSpec,
simply select RUN with Freerun and asynchronous timing (SYNCHRONOUS
not selected).
6.
Slowly move the detector in and out of focus. You should see the spectral line go
from broad to narrow and back to broad. Leave the detector set for the narrowest
achievable line.
7.
Next adjust the rotation. You can do this by rotating the detector while watching
a live display of the line. The line will go from broad to narrow and back to
broad. Leave the detector rotation set for the narrowest achievable line.
Alternatively, take an image, display the horizontal and vertical cursor bars, and
compare the vertical bar to the line shape on the screen. Rotate the detector until
the line shape on the screen is parallel with the vertical bar.
Note:
When aligning other accessories, such as fibers, lenses, optical fiber adapters,
first align the spectrograph to the slit. Then align the accessory without disturbing
the detector position. The procedure is identical to that used to focus the
spectrograph (i.e. do the focus and alignment operations while watching a live
image).
Focusing in Imaging Applications
Lens Performance Considerations
Imaging applications require that a lens be mounted to the detector. Because the lens
characteristics affect system performance, it may be helpful to review some basic lens
concepts. Basically, light from a subject enters the front of the lens and is focused to a
sharp image on the focal plane (CCD surface). The ability of the lens to do this well
depends on a number of factors, as follows.