Knowledge Bank

A Raman illumination system for the study of crystalline powders and polymers has been constructed. The system utilizes an improved version of the ""focal point"" mercury lamp of Moser and $Stieler.1$ The optimum operating conditions have been determined for the lamp and lifetimes in excess of 1800 hours have been attained. No appreciable darkening of the lamp window has occurred. A condenser and primary interference filter system is used to isolate the 4358{\AA} line and back-illuminate the sample. Optimum sample thickness studies have been made. Four interferences filters are used in reflection to eliminate approximately 93% of the exciting radiation prior to entry into the spectrograph. Quality spectra of both fine powders and polymers have been obtained with reasonable exposure times. The background is extremely low except when the sample fluoresces. Supported by a grant from the National Science Foundation.