Neutron Metrology in the United States-Where We've Been, Where We Are Now and What We Need to Do Moving Forward.

Neutron metrology in the United States must be based on traceability to standards maintained by the National Institute of Standards and Technology (NIST). This article reviews the history of NIST's neutron-metrology efforts, the loss of those capabilities, and attempts to restore them. Recommendations are made to ensure that neutron dosimetry performed in the United States meets the requirements set forth by the International Standards Organization and other international and national authorities.