Abstract: A fiber optic interface for laser spectroscopic Raman probes incorporating a housing with a window enclosure. The fiber optic interface minimizes stray light interference from window back reflections and provides high photonic efficiency through refractive manipulation of emission and reception fields. The illumination fiber is surrounded by collection fibers. The fiber bundle formed by the illumination fiber and the collection fibers is formed into a conical shape, which creates a refractive surface on the illumination fiber and each of the collection fibers. The refraction at the end faces steers the illumination and collection patterns toward the axis of the illumination fiber. This results in the reflected portion of the illumination light being reflected toward the illumination fiber, and in the collection pattern being coincident with the illumination pattern.

Abstract: There is disclosed an improved process for the preparation of phosphorus trichloride wherein elemental phosphorus is caused to react with chlorine. The improvement comprises continuous, high speed analysis of the contents of the reactor whereby the reaction is controlled to produce less phosphorus pentachloride and other by-products. The analysis is performed by a laser Raman spectrometer associated with an optrode having a remotely located probe head and a circulating sampling system to continuously provide fresh sample to the probe head continuously. Also disclosed is apparatus for the automatic control of the reaction by control of the reactant feed to the reactor in response to the on-line, continuous analysis of the reactor contents.

Abstract: There is disclosed an improved process for the preparation of phosphorus trichloride wherein elemental phosphorus is caused to react with chlorine. The improvement comprises continuous, high speed analysis of the contents of the reactor whereby the reaction is controlled to produce less phosphorus pentachloride and other by-products. The analysis is performed by a laser Raman spectrometer associated with an optrode having a remotely located probe head and a circulating sampling system to continuously provide fresh sample to the probe head continuously. Also disclosed is apparatus for the automatic control of the reaction by control of the reactant feed to the reactor in response to the on-line, continuous analysis of the reactor contents.