Thin film personal dosimeters for detecting toxic propellants. AMRL-TR-66-231.

A portable system for the detection of low concentrations of nitrogen tetroxide (N2 0 4 ), fluorine (F 2 ), and unsymmetrical dimethylhydrazine (UDMH) in air has been developed. The detection system is based upon the change of electrical resistivity of thin metal films when exposed to these gases. Silver metal films coated with appropriate salts proved to be applicable to the detection of all three gases. However, the following metal films were found to be optimum: for N 2 0 4 , silver; F 2 , copper; and for UDMH, gold. Using the best film and salt combinations found to date, N 2 0 4 could be monitored over the range of 0. 1 to 50 ppm, F? over the range 1. 0 to 100 ppm, and UDMH over the range 10 to 1000 ppm, with a standard deviation of about 20 qercent. The effects of temperature over the range 50 to 90OF and of humidity from 10 to 90 percent R. H. on the response characteristics of the thin film sensors were found to be significant.