Elastic radiation scatter-detecting safety device analyzer apparatus

Abstract

A safety device for detecting elastically scattered radiation comprises: an excitation source of substantially monochromatic radiation having a controllable output, a detector for detecting elastically scattered radiation collected from a specimen illuminated by the excitation source, and a signal conditioning circuit that comprises a transducer and a comparator. An output transducer signal representative of the elastically scattered radiation is compared with a predefined threshold signal. If the output transducer signal is less than the threshold signal, a control output signal coupled to the excitation source causes the output of the source to be reduced. The safety device is included in an analyzer apparatus, preferably a Raman spectrometry apparatus that further includes an optical probe. The probe comprises a fluid-tight body that encloses three optical channels, preferably comprising optical fibers, that carry monochromatic radiation to a specimen and separately collect inelastically and elastically scattered radiation from the illuminated specimen. In a method for controlling a radiation source in an analyzer apparatus, a specimen is analyzed by an excitation source having a controllable output, preferably a laser. Elastically scattered radiation from the illuminated specimen is collected, detected, and transduced into an output transducer signal representative of the scattered radiation. If the output transducer signal is less than a predefined threshold signal, a control output signal coupled to the laser causes its output to be reduced.