Experimental Measurement Techniques.
NEW MEXICO STATE UNIV LAS CRUCES ENGINEERING EXPERIMENT STATION
Pagination or Media Count:
A pellet spectrophone has been designed and constructed to measure low level absorption by atmospheric dust and other particulate matter. It was shown that an absorption-to-scattering sensitivity greater than 50 can be achieved, which is a necessary property for measuring absorption at short wavelengths. Detection capability of microwatts of absorbed energy is also possible with this system. Therefore, milliwatt sources and microgram samples may be utilized. Even though the pellet spectrophone responds primarily to absorbed energy it does not result in any data directly convertible to determination of the imaginary part of the complex refractive index except, perhaps under special conditions. This is due to problems regarding particle size distribution and involvement of the real part in scattering interactions. However, if all of these problems are recognized, use of the pellet spectrophone does result in good measurements of the absorption coefficient of the suspended material at whatever wavelengths tested and at whatever size distributions that exist in the host KBr pellet.
- Test Facilities, Equipment and Methods
- Acoustic Detection and Detectors