June 29, 2023

A Fission-like Neutron Spectrum Shaping Assembly based on D-T Generator


For nearly five decades, 252Cf sources have been used for testing and calibration over a wide range of neutron detection devices used for nuclear safety and radiation protection. However, the vastly increased cost of 252Cf sources, its short half-life, and concerns about future shortage have prompted nuclear facilities and radiological calibration laboratories that rely on high-intensity neutron sources to seek alternatives. While there appear to be no other radionuclide neutron sources that would match the 252Cf performance characteristics, all of them, including 252Cf, present similar concerns in terms of hazards, safety, and security. As a possible solution to this issue, the Pacific Northwest National Laboratory (PNNL) developed a low-risk, cost-efficient alternative to produce fission-like spectra based on commercially available deuterium-tritium (D-T) neutron generators. The alternative of producing a fission-like neutron spectrum without any fissionable materials or beryllium would enable the nuclear facilities across the entire complex to eliminate their reliance on high intensity 252Cf sources for nuclear safety and radiation protection applications, substantially reducing risks and associated costs. This report describes efforts of designing the spectrum shaping assembly, its construction and characterization of the neutron field produced. Performance of this newly developed D-T generator based neutron field is demonstrated via calibration of a criticality detector, neutron survey instruments, and personal dosimeters verified against current standardized fields produced by 252Cf spontaneous fission sources.

Published: June 29, 2023


Mozhayev A.V., R.K. Piper, J.F. Christ, J.E. Turner, R. Guerrero-Godinez, and A.L. Maine. 2023. A Fission-like Neutron Spectrum Shaping Assembly based on D-T Generator Richland, WA: Pacific Northwest National Laboratory.

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