Ultraviolet Detector : A flame detector that has a sensing element that responds to radiant energy outside the range of human vision in the ultraviolet range (below approximately 4,000 angstroms)
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}