The National Institute of Standards and Technology (NIST) is seeking sources for an Aerodynamic Aerosol Classifier (AAC) and Particle Mass Analyzer (PMA) to support semiconductor process chemical metrology. The required equipment must classify aerosol particles by aerodynamic diameter from 25 nm to >5 µm and by mass-to-charge ratio at masses >0.2 ag with a mass resolution >5. NIST intends to award a sole source contract to CAMBUSTION LTD in Cambridge, United Kingdom, unless other capable vendors are identified through this market research. Responses are due by July 8, 2026, and questions must be submitted by June 25, 2026. Performance location is not specified.