13
U-CBR1, U-CBR2
If the specimen does not become dark even after rotating the stage, the retardation of the
specimen is outside the measurable range, and measuring with the U-CBR1 or U-CBR2
is not possible. (See page 1)
6. To find the retardation, insert the read angles into the following formula:
Retardation (nm) = R
0
· sin (2 ·
│
θ
–
θ
0
│
)
R
0
= Compensator constant (This can be found in the attached data sheet.)
θ
= Angle at the extinction position of the measuring point when the specimen is placed on
the stage.
θ
0
= Angle when the field of view becomes dark when the specimen is not placed on the stage
(fiducial point)
│
θ
–
θ
0
│
When the values of both
θ
and
θ
0
are indicated by digits of the same color
→
θ
–
θ
0
When the values of
θ
and
θ
0
are indicated by digits of ditterent colors
→
θ
+
θ
0
Example:
·
θ
= 25.4° (black),
θ
0
= 0.5° (black)
│
θ
–
θ
0
│
= 25.4° – 0.5°
= 24.9°
·
θ
= 22.3° (green),
θ
0
= 0.2° (black)
│
θ
–
θ
0
│
= 22.3° + 0.2°
= 22.5°
