The National Institute of Standards and Technology (NIST) is seeking sources for a brand-name Mirion Technologies pin-well detector system to enhance its capability for primary standardization of difficult-to-measure radionuclides that decay by electron capture. The required system includes a 3”x3” NaI(Tl) detector with integrated photomultiplier tube, preamplifiers, cabling, a multi-channel analyzer, backup MCA, and data acquisition/analysis software with a perpetual license. Performance of services is at NIST’s facilities, with FOB Destination delivery required. No budget amount is specified. Responses to this sources sought notice are requested as soon as possible, with questions due by 12:00 PM ET on June 8, 2026.