Spm Head; Laser Beam Focusing - JEOL JSPM-5200 Instructions Manual

8.3

SPM HEAD

8.3.1

Laser Beam Focusing

The laser beam has been adjusted in the factory before shipment so that it is focused on
the tip of the cantilever. If, however, the beam becomes out of focus for some reason,
re-adjust the focus according to the following procedure.
Due to scattering, the spot size of the laser beam looks considerably larger than its real
size when it illuminates an object (specimen or cantilever). If you feel any abnormality
with focusing, check the position and angle of the cantilever again before adjusting the
focus.
1.
Loosen the locking screw of the focus-adjusting screw using the provided
flat-blade screwdriver.
2.
Mount a specimen stub, with no specimen on it, on the standard specimen
holder. Elevate the specimen stub using the manual approach thumbscrew
until it rises flush with the cantilever tip.
3.
The optical microscope with CCD adjust the laser beam by turning the two
laser-beam positioning knobs and the focus adjusting screw by the same
amount in the same direction so that the beam spot size becomes as small
as possible on the specimen stub.
4.
Install the cantilever as usual and illuminate the tip of the cantilever with the
laser beam.
5.
Maximize SUM by adjusting the laser-beam position using two laser-beam
positioning knobs. Make a note of the SUM value at that time.
6.
Adjust the focus-adjusting screw and the two laser-beam positioning knobs
by one half revolution in the same direction and then maximize SUM again.
7.
Repeat steps 5 and 6 above until the largest SUM value is obtained.
8.
Tighten the locking screw after adjustment.
TMPM5200-2
Focus-adjusting
screw
Be careful not to get irradiation bombardment from the laser
radiation aperture locating near the laser source position
adjusting knobs.
Flat-blade screwdriver
Laser-beam
positioning knobs
WARNING
8 GENERAL
8-3