Princeton Instruments PhotonMAX System, Manual, Page: 38 / 98

38 PhotonMAX System Manual Version 1.B
Figure 22. Experiment Setup|Timing tab page
Focusing
The mounting hardware provides two degrees of freedom, focus and rotation. In this
context, focus means to physically move the camera back and forth through the focal
plane of the spectrograph. The approach taken is to slowly move the camera in and out of
focus and adjust for optimum while watching a live display on the monitor, followed by
rotating the camera and again adjusting for optimum. The following procedure, which
describes the focusing operation with an Acton SP-2356 spectrograph, can be easily
adapted to other spectrographs.
1. Mount a light source such as a mercury pen-ray type in front of the entrance slit
of the spectrograph. Any light source with line output can be used.
Standard
fluorescent overhead lamps have good calibration lines as well. If there are no
"line" sources available, it is possible to use a broadband source such as tungsten
for the alignment. If this is the case, use a wavelength setting of 0.0 nm for
alignment purposes.
2. With the spectrograph properly connected to the camera, turn the power on, 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 slit to 25 µm. If necessary, adjust the Exposure Time to maintain optimum
(near full-scale) signal intensity.
Select
"Fast Mode"