this is a sensor for , and a method of , determining if a particular type of flame is present , using at least two uncooled hgcdte detector films on a common ir transmissive substrate . specific examples of the types of radiation which can be identified include gasoline flames , natural gas flames , and organic combustion flames . the ratio of carbon dioxide to carbon monoxide can also be determined . the sensor can include a first hgcdte filter on a common ir transmissive substrate , a first uncooled hgcdte detector film over the first filter , and a second uncooled hgcdte detector film on a cdte insulator which is either on the first uncooled hgcdte detector film , or on a second hgcdte filter provided on the common ir transmissive substrate .