Princeton Instruments PI-MAX 3 System, Manual, Page: 126 / 150

126 PI-MAX
®
3 System Manual Version 1.A
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 slit to 25 µm. If necessary, readjust the SuperSYNCHRO frequency to
maintain optimum (near full-scale) signal intensity.
4. 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.
Note that the way focusing is accomplished depends on the spectrograph, as follows.

Long focal-length spectrographs such as the Acton SP-2300i: The
mounting adapter includes a tube that slides inside another tube to move the
detector in or out as required to achieve optimum focus.

Short focal-length spectrographs: there is generally a focusing mechanism
on the spectrograph itself which, when adjusted, will move the optics as
required to achieve proper focus.

No focusing adjustment: If there is no focusing adjustment, either provided
by the spectrograph or by the mounting hardware, then the only recourse will
be to adjust the spectrograph’s focusing mirror or to shim the detector.
5. 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).
Spectrograph Adapter Kit Page
Acton Sliding Tube 127
Acton C-Mount Adapter 128
Chromex 250 IS 7050-0090 129
ISA HR 320 7050-0010 130
ISA HR 640 7050-0034 131
SPEX 270M 7050-0041 132
SPEX 500M 7050-0038 133
SPEX TripleMate 7050-0007 134
Table 8. Spectrograph Adapters