We have assembled an ultraviplet-sensitive intensified camera for observing hydrogen combustion by imaging the OH, A2Σ+ - x2II bandhead emissions near 309 nm. The camera consists of a quartz and CaF achromat lense-coupled to an ultraviolet image intensifier which is in turn fiber-coupled to a focus projection scan (FPS) vidicon. The emission band is selected with interference filters which serve to discriminate against background. The camera provides optical gain of 100 to 1000 and is capable of being shuttered at nanosecond speeds and of being framed at over 600 frames per second. We present data from observations of test flames in air at standard RS-170 video rates with varying background conditions. Enhanced images using background subtraction are presented. Finally, we discuss the use of polarization effects for further discrimination against sky background. This work began as a feasibility study to investigate ultraviolet technology to detect hydrogen fires for the NASA space program.
George J. Yates,
"Ultraviolet Imaging Of Hydrogen Flames", Proc. SPIE 0932, Ultraviolet Technology II, (16 August 1988); doi: 10.1117/12.946900; https://doi.org/10.1117/12.946900