In a spectrophotometer, a position of a motor corresponding to a 254 nm bright line in the last check is read out from a memory section, and only a low-pressure mercury lamp is lighted up to scan a grating around the 254 nm line position in the last check, so that the 254 nm line position where a 254...http://www.google.fr/patents/US6795180?utm_source=gb-gplus-shareBrevet US6795180 - Spectrophotometer
