@prefix cpm: . @prefix dc: . @prefix dcat: . @prefix dce: . @prefix dct: . @prefix dcterms: . @prefix grg: . @prefix iop: . @prefix ns0: . @prefix ns1: . @prefix owl: . @prefix pav: . @prefix prov: . @prefix puv: . @prefix qudt: . @prefix rdf: . @prefix rdfs: . @prefix reg: . @prefix sdo: . @prefix semapv: . @prefix skos: . @prefix sssom: . @prefix void: . @prefix xsd: . rdf:type sdo:DefinedTerm ; sdo:description "The compact Fluorescence Assay by Gas Expansion (FAGE) instrument is used in ship and aircraft deployments to measure hydroxyl radicals (OH) and iodine monoxide radicals (IO). It uses low pressure Laser Induced Fluorescence (LIF). The laser, tuned to 308 nm for OH or to 445 nm for IO, is directed through the ambient air sample. The resulting fluorescence is filtered and focussed onto a photomultiplier tube, and analysed by photon counting. The signal is calibrated using known standards of OH and IO."@en ; sdo:inDefinedTermSet ; sdo:name "University of Leeds compact Fluorescence Assay by Gas Expansion instrument"@en ; sdo:termCode "SDN:L22::TOOL0436" .