Checking The Infrared Alignment - PerkinElmer Spotlight 200 User Manual

86 . Spotlight 200 User's Guide
2. Move the ATR crystal holder using the adjusting levers until it is centered.
One lever moves the assembly backwards and forwards and the other from side to side.
3. Tighten the knurled thumb-nuts.
4. Move the microscope slide to a fresh area of tape.
5. Lower the crystal onto the tape.
6. Retract the crystal.
7. Look through the microscope at the impression of the crystal on the tape. Decide
whether the impression is in the center of the field of view.
8. If necessary, repeat steps 1 to 7 until the ATR objective is aligned.

Checking the Infrared Alignment

The following procedure allows you to determine the energy reaching the detector when the
ATR crystal is in place. If the crystal is aligned correctly, the energy level measured should
be at least 20% of the maximum energy measured in reflectance mode; see
Maximum Energy in Reflectance Mode
1. Place the slide holding the reference mirror (supplied with the microscope) on the
sample stage.
2. Look at the image in the Camera View pane and focus the microscope on the surface of
the mirror with the Z-control on the joystick, or the Auto-Focus option.
There are usually dust particles or scratches on the surface that you can use to focus
on.
3. Lower the crystal on to the reference mirror.
You should lower the crystal and then raise the stage slowly with the manual ATR
objective. For the automated ATR objective, click the Contact Sample button on the
Setup Microscope Basic tab once the crystal is lowered.
4. Enter 100 in the Aperture Width and Height text boxes on the Setup Microscope
Advanced tab.
5. To monitor the energy reaching the detector, select Monitor from the Measurement
toolbar and choose the Energy option.
6. Record the level of energy measured and compare it with the value measured when the
crystal is retracted.
If the energy is less than 20% of the maximum energy measured, repeat the alignment
procedure on page 85.
7. Click Halt.
Alternatively, you can measure the energy in reflectance mode before and after lowering the
ATR crystal on to the mirror. The software displays the maximum energy with the crystal
retracted, and then shows the current energy when ithe crystal is lowered.
on page 83 for details.
Measuring the