IMPROVED SYSTEM FOR DETECTING COMPOUNDS IN A GASEOUS SAMPLE USING INDUCED PHOTOIONIZATION FOR ELECTRON CAPTURE DETECTION

摘要

This present disclosure is directed toward the measure of very small concentrations of compounds of interest within gaseous samples. A spark discharge system induces pulsed spark discharges across a pair of electrodes within an inert gas in a gas flow chamber. Various reactions are induced by spark interaction with the flow of inert gas, and with any sample or dopant commingled with the inert gas, in the region of the pulsed spark discharge. This induces photon ionization which creates an instantaneous current flow within the gas flow chamber. Current flow is held constant for all concentrations of sample introduced into the gas flow by means of a control feedback system. The output of the control feedback system is indicative of sample concentration. The system responds linearly over approximately five orders of magnitude of sample concentration for use with the sample which will be described and low femtogram sensitivity is achieved.