Patent ID: 7087907

Claim:
A process for detection of contamination in an imaging system, comprising providing an imaging system having one or more element having a surface for reflecting or refracting first incident radiation; mounting with respect to at least one of the one or more element one or more detector capable of sensing third radiation emitted or transmitted by one or more contaminant on the surface of the one or more element when second radiation is absorbed by the one or more contaminant; applying the first incident radiation and/or the second radiation to the at least one element; and detecting with the one or more detector the third radiation emitted or transmitted by the one or more contaminant wherein the contaminant comprises one or more of an organic contaminant, a fluorinated alkane-based contaminant, a fluorinated ether-based contaminant, a siloxane contaminant, a sulfur-based contaminant and an iodine-based contaminant.