GENERAL INFORMATION This is combined sources sought notice and notice of intent to sole source. The purpose of this notice is to conduct market research and identify potential sources of commercial products/services that satisfy the Government's anticipated needs. If no alternate sources are identified, as a result of this notice, the Government intends to issue a sole source award to CAMBUSTION LTD, Unit J6 The Paddocks 347 Cherry Hinton Road Cambridge CB1 8DH, United Kingdom (UEI: UPTMD12PY5J1), under the authority of FAR 13.106-1(b) (1)(i). NIST conducted market research from December 2025 through March 2026 by conducting internet searches; utilizing GSA and SAM.gov; reviewing professional journals and published literature; and speaking with colleagues, other professionals, and vendors to determine what sources could meet NIST's minimum requirements. The results of that market research revealed that only CAMBUSTION LTD appears to be capable of meeting NIST's requirements as they are the only vendor that manufactures an Aerodynamic Aerosol Classifier (AAC) capable of classifying aerosol particles by aerodynamic diameter from 25 nm to > 5 μm and a Particle Mass Analyzer (PMA) capable of classifying aerosol particles by mass to charge ratio at masses > 0.2 ag (2 × 10^-19 g, equivalent to a 7 nm diameter particle with unit density) at a mass resolution (Δm/m) > 5. If other capable vendors are identified as a result of this notice, that information will be reviewed and considered so that the NIST may appropriately solicit for its requirement. The North American Industry Classification System (NAICS) code for this acquisition is 334516 - Analytical Laboratory Instrument Manufacturing, with a Small Business Size Standard of 1,000 employees. This notice does not constitute a Request for Proposal (RFP), Request for Quotation (RFQ), Invitation for Bids (IFB), or any commitment by the Government to issue a solicitation or award a contract. The National Institute of Standards and Technology (NIST) will not pay for any information submitted in response to this notice. Submission of information is voluntary and will not result in any obligation on the part of the Government. NO SOLICITATION DOCUMENTS EXIST AT THIS TIME Requests for solicitation documents will not receive a response. Respondents shall clearly mark any proprietary or restricted information. In the absence of such markings, NIST will assume unlimited rights to all technical data submitted. BACKGROUND The National Institute of Standards and Technology requires an Aerodynamic Aerosol Classifier (AAC) and Particle Mass Analyzer (PMA) to establish a high-fidelity metrological framework for characterizing sub-50 nm impurities in semiconductor process chemicals, specifically ultrapure water. Unlike traditional mobility-based classification, the AAC and CPMA allow for the independent determination of a particle's aerodynamic diameter and mass without the uncertainties introduced by ele…