Goniometers
This page describes the goniometers, sample holders, and light sources that are available at C-TAPE:
1. Goniometers
C-TAPE is equipped with three goniometers that can be interfaced with a variety of the laboratory's spectrometers and light sources, and allow for in-plane bidirectional measurements across a wide range of angles. The goniometers can be used in conjunction with lightboxes to isolate the samples from all ambient light. We have also developed methodologies and accessory units that allow for off-axis (out of plane) bidirectional measurements of any combination of incidence and emission angles and azimuth.
We have also developed a capability to allow for acquisition of reflectance-like spectra of single mineral grains using an aluminum sample holder with small-diameter wells that interfaces with standard 8 mm diameter fiber optic probes.
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2. Light sources
| C-TAPE is equipped with a number of in-house light sources for various applications. The main light source consists of a changeable Quartz-Tungsten-Halogen (QTH) bulb housed in an integrating sphere that consists of two connected aluminum reflectors and a hollow-core light pipe that allows light to be directed onto a sample with a spot size of a few millimeters to few centimeters, depending on the distance from the sample. Fiber optic cables can also be integrated with the light source for various types of illumination. Stabilized DC power is provided via BK Precision model 1621a and 1666 DC regulated power supplies (depending on required power levels). A variety of QTH bulbs are available for different applications in the lab: 11 W fiber-optic light, 20, 50, 100, 150 W fiber optic light or light pipe, and a 500 W QTH spotlight. |  |
Broadband ultraviolet illumination is available with an Analytical Instrument Systems Inc. (AIS) Model Mini-DTA 30 watt deuterium light source. This source allows for the acquisition of reflectance spectra to as low as 200 nm and can be used in conjunction with other instruments or as a stand-alone UV light source or illuminator.
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Other light sources available at C-TAPE include an IR 12k glow bar built into an aluminum housing, a UV three-wavelength light bar (252, 306, 365 nm), as well as 365 nm spotlights, and 405 nm and 532 nm lasers.