Spectrograph Adapters; Spectrograph-Detector Focusing - Princeton Instruments PI-MAX System Manual

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Spectrograph Adapters

Princeton Instruments offers a variety of spectrograph adapters for mounting a PI-MAX
to a spectrograph: Acton (adapters are available for all Acton models), the ISA HR320,
ISA HR640, Chromex 250IS, and most instruments that are 1 meter or longer. (If you are
not sure of the depth of the exit focal plane, contact the spectrograph manufacturer.)
Mounting the camera to one of these spectrographs typically requires a female Focusing
Flange that may be a separate part or an integral part of the spectrograph. Also required is a
male Focusing Flange that slides into the female flange to set the focus and which is bolted
to the spectroscopy-mount adapter that screws into the PI-MAX nose.
The mounting instructions for spectrograph adapters offered by Princeton Instruments
are organized by spectrograph model and adapter kit number. For the appropriate
instruction set, see Table 14, page 205, which cross-references these items with the
page number.
Note: When mounted to a spectrograph, the text on the back of the PI-MAX should
be right side up.

Spectrograph-Detector Focusing

The detector mounting hardware provides two degrees of freedom: focus and rotation.
In this context, focus means to physically move the detector back and forth through the
focal plane of the spectrograph. The approach taken is to slowly move the detector in and
out of focus and adjusting for optimum while watching a live display on the monitor,
followed by rotating the detector and again adjusting for optimum. The following
procedure, which describes the focusing operation with an Acton 2300i 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 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 spectrograph properly connected to the controller, 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, readjust the Exposure Time 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.

PI-MAX/PI-MAX2 System Manual
Long focal-length spectrographs such as the Acton 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.
Version 5.F