NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Preparation and calibration of a Protactinium-231 reference material
Published
Author(s)
Richard Essex, Ross W. Williams, Kerri C. Treinen, Ronald Colle, Ryan P. Fitzgerald, Raphael Galea, John Keightley, Jerome LaRosa, Lizbeth Laureano-Perez, Svetlana Nour, Leticia Pibida
Abstract
A 231Pa reference material has been characterized for amount of Pa. This reference material is primarily intended for calibration of 233Pa tracers produced for 231Pa - 235U model age measurements associated with nuclear forensics and nuclear safeguards. Primary measurements for characterization were made by isotope dilution mass spectrometry of a purified 231Pa solution using a 233Pa spike. The spike was calibrated by allowing multiple aliquots of the 233Pa spike solution to decay to 233U and then measuring the ingrown 233U by isotope dilution mass spectrometry using a certified uranium assay and isotopic standard as a reverse-spike. The new 231Pa reference material will simplify calibration of the 233Pa isotope dilution spikes, provide metrological traceability, and potentially reduce the overall measurement uncertainty of model ages.
Essex, R.
, Williams, R.
, Treinen, K.
, Colle, R.
, , R.
, Galea, R.
, Keightley, J.
, LaRosa, J.
, Laureano-Perez, L.
, Nour, S.
and Pibida, L.
(2019),
Preparation and calibration of a Protactinium-231 reference material, Journal of Radioanalytical Nuclear Chemistry, [online], https://doi.org/10.1007/s10967-019-06711-6
(Accessed October 21, 2025)