Labsphere DRA-CA-3300 User manual

AQ-00275-000, Rev. 3
DRA-CA-3300 Diffuse Reflectance Accessory
Introduction .............................................................................................................. 1
Unpacking and Inspection ....................................................................................... 3
Standard Components ....................................................................................3
Optional Components ....................................................................................3
Installation ................................................................................................................ 5
Optical Alignment of the Accessory ....................................................................... 8
Alignment Check ...........................................................................................8
Aligning the Accessory Optics ......................................................................9
Diagnostic Scans ..........................................................................................11
Operation ................................................................................................................ 14
Integrating Sphere ........................................................................................14
Optical Chamber ..........................................................................................15
Loading the Sample Reflectance Port ..........................................................15
Transmittance Sample Holder ......................................................................17
8°/Hemispherical Reflectance Factor Measurements .................................. 17
0°/Diffuse Reflectance Factor Measurements ..............................................18
Large Sample Reflectance Measurements ...................................................18
Transmittance Measurement Procedure .......................................................19
Theory of Operation .....................................................................................21
Double Beam Spectroscopy .........................................................................21
Reflectance Measurement of Non-Ideal Samples ........................................24
Zeroline Correction ......................................................................................26
Sources of Error ...........................................................................................26
Optional Components ............................................................................................ 28
Center Mount Sample Holders ....................................................................28
Powder Cell Holder ......................................................................................35
Transmittance Port Cuvette Holder ..............................................................37
Maintenance ........................................................................................................... 39
Mirror Cleaning Procedure ..........................................................................39
Spectralon Care Guide .................................................................................39
Troubleshooting the DRA-CA-3300 ............................................................40
Detector Replacement ..................................................................................41
Appendix A Specifications .................................................................................... 42
Appendix B Typical Spectralon Reflectance Factors ......................................... 43
Appendix C Glossary ............................................................................................ 44

AQ-00275-000, Rev. 3 1
Introduction
The traditional use of the spectrophotometer is to measure the transmittance of a clear or translu-
cent liquid or solid. Typical UV/VIS spectroscopy applications in this regard include reaction
kinetics, quantitative analysis or the simple identification of the chemical constituents in a sub-
stance. The measurement of reflectance offers an added dimension to the spectroscopy capabilities
of your spectrophotometer - your analysis is no longer limited to the portion of the beam that pen-
etrates the sample. Accordingly, you are no longer limited to samples that are clear or translucent.
The diffuse reflectance accessory (DRA) provides the means of measuring opaque, turbid and
reflecting substances using the same basic procedures used in traditional measurements.
Your DRA-CA-3300 is an integrating sphere accessory that replaces the sample compartment of
your spectrophotometer. An integrating sphere is a hollow optical device, either constructed from
or coated internally with a white diffusing material and fitted with the same detector as your spec-
trophotometer. At Labsphere, we use one of several proprietary reflective coatings in our reflec-
tance accessories, depending on the wavelength of your spectrometer and your application. The
integrating sphere collects the radiation from the sample and reference beams and measures the
signals for display by your CARY WinUV software.
Figure 1. The DRA-CA-3300 replaces the existing sample compartment of the
CARY 100 or CARY 300 spectrophotometers.

AQ-00275-000, Rev. 3 2
The integrating sphere configuration offers some distinct advantages over the standard sample
compartment. Reflectance samples are mounted inside the sphere on Labsphere accessories,
thereby affording collection of the entire sample beam of your spectrophotometer. For transmit-
tance measurements, the location of the sample holder at the sphere transmittance port expands the
cone of scattered radiation produced by the sample. The changes made in sample beam geometry
on your accessory do not compromise the transmittance and absorption measurement capabilities
already inherent in your spectrophotometer - you can still carry out the traditional transmittance
and absorbance measurements as before.
The DRA-CA-3300 reflectance accessory is designed for use with the CARY 100/300 UV-VIS
Spectrophotometers. The sphere accessory is an optical bench composed of double beam transfer
optics in combination with a six-inch (150 mm) diameter integrating sphere. The integrating
sphere of the DRA-CA-3300 is machined from Labsphere's proprietary SpectralonTM highly dif-
fuse reflectance material. The accessory is equipped with a movable mirror in the sample beam
optics to allow the beam to be focused at the transmittance, reflectance, or center-mount sample
positions. This adds versatility for measuring various size samples. The DRA-CA-3300 is
designed to perform reflectance, transmittance, or absorbance measurements of diffuse, specular,
or mixed samples. You will need the scan module of the CARY WinUV software to perform mea-
surements with your accessory.

AQ-00275-000, Rev. 3 3
Unpacking and Inspection
The DRA-CA-3300 accessory was thoroughly inspected and tested before shipping and should be
ready to operate after completing the set-up instructions. All Labsphere instrumentation is pack-
aged and shipped in reinforced shipping containers. Carefully check the components after unpack-
ing for any damage that may have occurred during shipping. If there is any such damage, file a
claim immediately with the freight carrier and contact the Labsphere Customer Service Depart-
ment at
![phone].
Standard Components
• DRA-CA-3300 Accessory with instruction manual
• Tool Kit
• Three USRS-99-020 Uncalibrated Spectralon Reflectance Standards
• Center-mount Port Plug
• Reflectance Port Light trap (fits in sample holder)
• One 0° and two 8° wedge assemblies, to fit in sample holder assemblies
• Transmittance Port Sample Holder
• Optics (dust) Cover
• (2) Sample Holder Assemblies, for reference and sample ports
• Alignment Pin
• Reference port aperture plate
• Two Thin Sample Holders (Part No. AS-01526-000)
• Quality Assurance Documents
Optional Components
In addition to the optional components listed here, Labsphere can design and manufacture custom
components for the DRA-CA-3300. Contact your Labsphere sales representative for information
on optional and custom accessory products.

AQ-00275-000, Rev. 3 4
• Cuvette Holders: Sample or Reference Port(1 cm path length)
• SRS-99-020 Calibrated Spectralon Reflectance Standard
• Variable Angle Center-mount Sample Holders (VASH), Clip - used for analyzing
thin films
• Variable Angle Center-mount Sample Holders, Jaw - used for analyzing opaque,
rigid solids
• Fixed Angle Center-mount Sample Holder--Cuvette (1 cm path length)
• Aperture Set, Reflectance Sample Port
• Transmittance Port Cuvette Holder

AQ-00275-000, Rev. 3 5
Installation
Your DRA-CA-3300 accessory comes already assembled - all you have to do is load the unit into
the sample compartment of your spectrophotometer.
WARNING: Do not touch the mirrors of the accessory. Fingerprints will induce optical scattering
and may reduce reflectance or transmittance of these components at certain wavelengths. Only
qualified service personnel should install reflectance accessories.
1. Turn the power to the instrument OFF. Remove any cell holders or other accessories
from the instrument sample compartment.
2. Slide the instrument sample compartment cover back. Remove the compartment front
panel. Note the position of the detector DB connector inside the compartment.
3. Install the alignment pin into the threaded mounting hole located at the back, right-
hand corner of the instrument sample compartment as shown in Figure 2.
4. Remove the optics dust cover from the DRA-CA-3300 by first loosening the top two
thumbscrews and then lifting the cover off. The cover should be reinstalled over the
Alignment Pin
Front Mounting Screws
Rear Mounting Screw
Sample Compartment
Accessory Base Plate
Figure 2. Mounting the accessory onto the sample compartment floor.

AQ-00275-000, Rev. 3 6
optics chamber only when the accessory is in storage and not being used.
5. Make sure mirror M3 is set to the reflectance "R" position; the reflectance position is
the one closes to the front of the accessory. To move this mirror, loosen its mounting
screw, lift the mirror off the baseplate and move it to the reflectance position "R"
nearestthe sphere. Set the mirror alignment pins into the correct locator holes. Secure
M3 in place with the mounting screw shown in the figure below.
NOTE: The DRA-CA-3300 is heavy and somewhat awkward to lift and maneuver. Installation may
require two people and the use of a step-stool.
6. Remove all packaging material from the optical chamber.
7. Slide the accessory into the sample compartment area. If the accessory is already
aligned, feed the accessory detector cable through the cutout on the base mount and
plug the connector into the instrument. Otherwise, install the accessory with the cable
unconnected.
8. Position the accessory over the alignment pin in the back until the head of the assem-
bly fits tightly against the front panel of the instrument. You may have to apply slight
pressure to compress the foam gasket. Adjust the height of the accessory’s foot to
help support its weight.
9. Taking care not to scratch the mirrors, tighten the two front captive mounting screws
and the rear mounting screw illustrated in Figure 2.
10. Remove the handle from the accessory using a slotted screwdriver. Make sure the
detector cable does not obstruct the beam path inside the optical chamber of the
accessory.
11. Open the accessory lid and install the center mount port plug into the top of the
sphere. Install the transmittance sample holder at the sample transmittance port - it
should slide easily into the dovetail cutout just behind the sphere with the metal clips
pointing up. Close the lid to the accessory. Slide the instrument sample compartment
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M3
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PinsScrew
Figure 3. Mirror M3 may be moved to any one of
three mounting positions.

AQ-00275-000, Rev. 3 7
cover to its closed position.
12. Slide a sample wedge into the dovetailed plate at the sample reflectance port. The
coated side should face the integrating sphere. Install the sample clamp over the
dovetail.
13. Install the 0°reference wedge at the reference port in the same manner as above.
14. Install the reflectance standards in the sample holders at the sample reflectance and
reference ports.
15. Store the optics chamber cover, handle and front panel to the spectrophotometer sam-
ple compartment in a safe place.
16. Upon first-time installation, check the optical alignment of the accessory as described
in the Optical Alignment Section of this manual. Confirm proper functioning of the
accessory by performing the diagnostic scans described in the Operation Section of
this manual.
8 Wedge
Dovetail
Sample Clamp
Reference or Sample
Reflectance Port
Reflectance Standard
Figure 4. Either an 8° or 0° wedge can be installed at the sample
reflectance port. Normally, the 0° wedge goes at the reference port.

AQ-00275-000, Rev. 3 8
Optical Alignment of the Accessory
The transfer optics of the accessory were factory aligned prior to shipping. However, it is good
practice to ensure that misalignment did not occur in transit. The following procedure can be used
to check optical alignment of the accessory.
Note: The DRA-CA-3300 was aligned with mirror M3 in the reflectance measurement position.
This mirror position is located closest to the integrating sphere. Any time mirror M3 is moved to
the transmittance or center mount position, the accessory must be realigned.
Alignment Check
You can use this procedure to check the optical alignment of your accessory without disturbing any
mirror adjustments. You will need a one inch square of translucent paper that clearly displays the
outline of the sample or reference beam when illuminated. When performing this procedure, the
accessory control cable should be disconnected from the instrument. A top view illustration of the
accessory is provided in Figure 5.
1. Load diffuse reflectance standards at the reference and sample reflectance ports.
2. Turn on the instrument and boot the WinUV software.
Note: Do not drive instrument monochromator to zero with the detector cable connected, or
when instrument sample compartment is empty, as the increased energy at zero order may cause
damage to the detector system.
3. Darken the room and set the instrument for white light operation. White light opera-
tion can be established by booting the Align Application of WinUV, selecting the
Cary Tab and setting the following parameters:
Double Beam Normal
Y Mode %R
Ave Time 0.1
SBW 2
Slit Height Full

AQ-00275-000, Rev. 3 9
Click the Zero Order checkbox and select Apply.
4. Open the lid to the accessory and remove the center mount plug.
5. Slide the piece of translucent paper into the reflectance port sample holder just in
front of the standard. Examine the location of the sample beams relative to the port.
Check that the beam falls completely within the port surface area and does not over-
fill the port.
6. Repeat the previous step for the reference beam at the reference port.
7. Mount or hold the translucent paper at the transmittance port. Check that the sample
beam is confined to the surface area inside the transmittance port.
8. If the reference and sample beam positions meet the criteria specified in the previous
three steps, the accessory optics are aligned properly and no further alignment is nec-
essary. Turn off the spectrophotometer and re-install the accessory, this time making
the cable connection to the instrument.
Aligning the Accessory Optics
You can use this procedure to align your accessory if the unit is not already aligned or if the acces-
sory fails the alignment check. You will need a one inch square of translucent paper that clearly
displays the outline of the sample or reference beam when illuminated. When performing this pro-
cedure, the accessory control cable should be disconnected from the instrument.
1. Load diffuse reflectance standards at the reference and sample reflectance ports.
2. Turn on the instrument and boot the WinUV software.
3. Darken the room and set the instrument for white light operation. White light opera-
tion can be established by booting the Align Application of WinUV, selecting the
Cary Tab and setting the following parameters:
Click the Zero Order checkbox and select Apply.
Note: Do not drive instrument monochromator to zero with the detector cable connected, or
when instrument sample compartment is empty, as the increased energy at zero order may cause
damage to the detector system.
4. Open the lid to the accessory and remove the center mount plug.
5. Mirror M3 can be mounted at one of three positions on the accessory base plate. The
position closest to the integrating sphere is used for reflectance measurements at the
sample reflectance port. The position furthest from the sphere is for transmittance
measurements. The mirror position midway between the transmittance and reflec-
Double Beam Normal
Y Mode %R
Ave Time 0.1
SBW 2
Slit Height Full