AQ-00275-000, Rev. 3
19
2. Remove the enclosure assembly.
3. With a 3/32" hex driver, loosen the two hex socket screws that hold the sample holder
rail to the port frame.
4. Remove the entire sample holder assembly.
5. If necessary, loosen the two hex socket screws of the latch fixture and remove the
latch fixture so that the exterior surface surrounding the port is free of all attach-
ments.
Note: The sample surface should sit flush against the port frame to make a good light seal
with the port. If the sample does not make an adequate seal, cover the sample and port
with a dark cloth or darken the room. Ambient light from the room or even the instrument
light source compartment can add noise to spectra or even saturate the PMT detector
within the integrating sphere.
Transmittance Measurement Procedure
For transmittance measurements, make sure that mirror M3 is placed in the transmittance position,
marked "T" on the baseplate, located farthest from the sphere. If you move this mirror, you must
realign the transfer optics.
Repeat the alignment procedure if M3 has been moved. The "T" posi-
tion mirror configuration provides a condensed spot size of approximately 5 mm wide x 9.5 mm
high. If a large transmittance spot size is desired, such as for the measurement of fabrics or other
homogeneous samples, place mirror M3 in the reflectance "R" position. This mirror configuration
provides a spot size of approximately 11 mm wide x 28 mm high. If an intermediate spot size is
required, place the mirror in the center-mount "C" position.
1. Place the Spectralon standards into the sample reflectance and reference ports.
2. Load the reference into the appropriate sample holder:
a. If you are measuring a liquid, replace the transmittance sample holder with the
optional transmittance cuvette holder. You will need two identical cuvettes - the sam-
ple cuvette should hold the sample and solvent, the reference cuvette should be filled
with only the solvent. Load the reference cuvette at the transmittance port.
Note:
When taking transmittance measurements with cuvettes, make sure to only use
matched
cuvettes.
b. If you are measuring a solid, load the empty transmittance sample holder at the trans-
mittance port. The empty sample holder is normally used as the reference for transmit-
tance scans of solids. If the transmittance of a
treated
material relative to its substrate
is desired, the
untreated
substrate may be placed in the transmittance port as a refer-
ence.
c. If the sample is a fabric, slide the fabric sample holder with the filter onto the dovetail