For trace gas analyzers, semiconductor applications are among the most demanding with regard to instrument sensitivity and stability. Extremely high reliability and uptime are further hurdles instrumentation must demonstrate before being considered for such trace contaminant monitoring within the fab or to qualify feedstock gases. Picarro WS-CRDS trace gas analyzers represent the forefront of monitoring technology. These unbelievably stable, compact instruments provide the ideal combination of accuracy, precision and long-term un-manned operation while being insensitive to contaminants and changing environmental conditions.