OSCAR G2
Manual
D01-44en201810
Software V.1.1.6
(C)TriOS Mess- und Datentechnik GmbH
Bürgermeister-Brötje-Str. 25
D- 26180 Rastede/Germany
14 / 62
Therefore,
)
1
(
)
1
(
0
0
A
S
B
S
B
B
S
A
S
A
AB
P
P
P
P
P
P
T
(3)
P
0
and
P
s
are related to the radii of the PSICAM
r
0
=
r - r
s
and
r
, respectively, where
r
is the
inner radius of the cavity and
r
s
the radius of the central light source and to the absorption
coefficient
a
in the following way (see Kirk 1997 for details):
)
exp(
)
,
(
0
0
0
ar
r
a
P
(4)
)
1
2
)(
2
exp(
1
2
1
)
,
(
2
2
ar
ar
r
a
r
a
P
S
. (5)
Finally the transmission in the PSICAM is related to the absorption coefficients
a
A
and
a
B
of
the two solutions as
0
1
(
, )
(
, )
exp(
(
))
1
(
, )
(
, )
S
B
S
A
AB
A
B
S
A
S
B
P a r P a r
T
r a
a
P a r P a r
. (6)
When using Eq. (5) and (6),
T
AB
is a function of the light absorption of the samples
a
A
and
a
B
,
the radii
r
and
r
0
, and the reflectivity
. Solving Eq. (6) for the reflectivity gives
)
,
(
)
,
(
)
exp(
)
,
(
)
,
(
)
exp(
)
,
(
)
exp(
)
,
(
)
exp(
0
0
0
0
r
a
P
r
a
P
r
a
r
a
P
r
a
P
r
a
T
r
a
P
r
a
r
a
P
r
a
T
A
S
B
S
A
B
S
A
S
B
AB
A
S
A
B
S
B
AB
(7)
Hence, if
is not known, it can be determined by measuring the “transmission” induces by
two solutions with known absorption coefficients using Eq. (7) and (5).