Install the sample windows
The Pearl HTRN accessory comes with a set of zinc selenide (ZnSe) transmission windows that provide a 100 micron (0.10 mm) sample pathlength. The windows are a matched set. They are marked with the window material, serial number and sample pathlength, followed by a “W” (i.e., “wedged”) which means the bottom window is set at an slight angle. The angled bottom window optimizes the resulting sample spectra for both qualitative and quantitative measurements.
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Materials needed:
- Powder-free nitrile gloves
- Top window housing (provided)
- ZnSe top and bottom window assemblies (provided)
- 1.5 mm hex (or Allen) key ball driver (provided)
To install the transmission sample windows
- Gently pull out the accessory sample tray and make sure the tray is free of obstructions. If necessary, use a small, clean laboratory brush to remove any dust or debris.
Figure 1-1: HTRN accessory sample tray
- Install the bottom window assembly.
The bottom window assembly fits in the recessed area. Hold the bottom window assembly right side up (see image below) and gently lower it into the recessed area.
Figure 1-2: Bottom window assembly installation
- Carefully rotate the window assembly until its alignment hole (the larger of the two holes) fits over the alignment pin on the sample tray.
Figure 1-3: Alignment hole and pin fit together
- Install the top window assembly:
The top window assembly fits into the underside of the top window housing and is held in place by a set screw.
- Use the 1.5 mm hex key ball driver to loosen the set screw so that it doesn’t protrude into the recessed area (you don’t need to remove the set screw).
Figure 1-4: Recessed area and set screw access
- While holding the top window assembly right side up, line up the groove along the edge of the top window assembly with the alignment pin in the top window housing and gently lower the window assembly into the housing.
Figure 1-5: Groove and alignment pin
- Use the 1.5 mm hex ball driver to gently tighten the set screw.
| Do not overtighten the set screw or you may cause distortions in your acquired date. |
- For safekeeping, place the top window housing in the sampling position on the sample tray and close the tray. See the next section for details.
Top window housing - sampling and load position
The top window housing must be in the sampling position for data acquisition. Move the housing to the load position when you are ready to clean the sample windows or load a sample.
To place the top window housing in the sampling position
- Hold the top window housing right side up (see image below) and place it on the left side of the sample tray, lining up the alignment hole with the central alignment pin on the sample tray.
Figure 1-6: Top window housing in sampling position
To place the top window housing in the load position
- Lift the top window housing off the sample tray.
- Turn the top window housing upside down and place it on the right side of the sample tray, lining up the alignment hole with the central alignment pin.
Figure 1-7: HTRN top window housing in load position
