Remote Detection of Organochlorides With a Fiber Optic Based Sensor II. a Dedicated Portable Fluorimeter

Abstract

A dedicated portable fluorimeter, for use with fiber optic chemical sensors (FOCS) has been designed, constructed, tested, and calibrated. This represents a major advance in the development of a FOCS system suitable for in-field use. The portable fluorimeter uses an incandescent lamp, instead of a laser, for FOCS excitation and a photodiode, in place of a photomultiplier tube for detecting the fluorescence signal. It uses an optical system which is internally connected to a unitized optical block by 600 μm core optical fibers, to minimize alignment problems and increase overall system ruggedness. The system noise is less than .1.5 mV and the long-term drift is less than ±2 mV/hour. Measurements of organochloride were made at concentrations as low as 80 parts-per-billion with a signal to noise ratio of 40:1.