*****THIS IS A COMBINED SOURCES SOUGHT NOTICE AND NOTICE OF INTENT TO SOLE SOURCE***. BACKGROUND The National Institute of Standards and Technology (NIST) Physical Measurement Laboratory (PML), Nanoscale Device Characterization Division, Advanced Electronics Group intends to purchase a microwave resonator accessory add-on for NIST existing Bruker Biospin ELEXSYS-II E500 continuous wave X-band electron spin resonance (ESR) spectrometer. This cavity must be 100% compatible with the existing instruments software and hardware components. The only known company able to provide this needed equipment without sacrificing the integrity of the system or requiring substantial efforts to implement is Bruker Biospin. A primary strategic focus of the division involves utilizing ESR to resolve the chemical and physical nature of atomic-scale defects in materials. This research is critical for identifying and controlling defect entities responsible for critical failure and drift mechanisms in solid state devices. Furthermore, the ability to be quantitative, i.e. being able to count how many defects are present, is critical to evaluate different processing and materials synthesis steps. Thus, this procurement seeks an add-on accessory resonator capable of providing in situ quantitative measurements through a rectangular double cavity design, known as a TE104 variety microwave resonator. Furthermore, the new resonator must be fully compatible with the division's existing ESR infrastructure. This integration is vital to ensure operational continuity and to leverage established institutional expertise without requiring significant retraining or specialized knowledge deviation. NIST is seeking information from sources that may be capable of providing a microwave resonator. If no alternate sources are identified, the Government intends to issue a Sole Source Award to, Bruker Scientific under the authority of FAR 12.102(b) The North American Industry Classification System (NAICS) code for this acquisition is 334516. The microwave resonator must meet the following minimum specifications: The microwave resonator shall be fully compatible and seamlessly integrate into the NIST existing electron spin resonance spectrometer, a Bruker Biospin ELEXSYS-II E500 and its control software (proprietary Bruker Biospin software Xepr). The microwave resonator shall be fully compatible and seamlessly integrate with the auto tuning capabilities of the existing spectrometer. The microwave resonator shall be a double rectangular cavity operating in the transverse electric 104 mode (TE104). The microwave resonator shall have an unloaded Q value of at least 7000. The microwave resonator shall have a nominal resonance frequency of 9.7 GHz and support modulation frequencies between 1 kHZ and 100 kHz. HOW TO RESPOND TO THIS NOTICE In responding to this notice, please DO NOT PROVIDE PROPRIETARY INFORMATION. Please include only the following information, readable in either Microsoft Word 365,…