This is a firm fixed-price purchase order awarded by the National Aeronautics and Space Administration (NASA) Shared Services Center to Physikalisch-Technische Bundesanstalt (PTB) in Germany. The contract is for the irradiation of neutron detectors in various neutron fields, with a period of performance from December 4-6, 2019 and December 9-13, 2019. The total ceiling value of the contract is $28,401.10. This was a sole-source award under FAR 13.106-1(b)(1)(i), as PTB was determined to be the sole provider of the required services. There was no set-aside designation for this contract.