HP 5501A Operating And Service Manual page 50

L
WEIGHT:
11.2 ounces (316 grams)
DIMENSIONS:
See dimensional drawing.
REFLECTOR REQUIREMENTS:
Flatness: Must not deviate from a best-fit
plane by more than 0.1 micrometre
(3 microinches) over any 20 mm (0.8
inch) dimension.
Surface Finish: Metal 0.1-0.3 microinch
arithmetic average. Optical 80-40.
Maximum Angular Misalignment:
Depends on distance between inter-
ferometer and plane mirror. Typical
values are:
+25 arc-minutes for 254 mm (10 inches)
+15 arc-minutes for 510 mm (20 inches)
+5 arc-minutes for 1270 mm (50 inches)
Reflectivity: 80% minimum recommended
M-40 SCREWS
(2)
CLEARANCE FOR 64 OR (2.5 mm)
NOTE
Plane mirror flatness will determine system accuracy
for X-Y stage. For example if X axis mirror is out
of flat by 20 microinches (0.5 micrometre) this will
cause 20 microinch error in Y position.
Figure 2-23. 70706A Plane Mirror Interferometer Specifications