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.
Primary activity measurement of an Am-241 solution using microgram inkjet gravimetry and decay energy spectrometry
Published
Author(s)
Ryan Fitzgerald, Bradley Alpert, Denis Bergeron, Max Carlson, Richard Essex, Kelsey Morgan, Shinichiro N. Muramoto, Svetlana Nour, Galen O'Neil, Daniel Schmidt, Gordon Shaw, Daniel Swetz, R Verkouteren
Abstract
We demonstrate a method for radionuclide assay that is spectroscopic with 100 % counting efficiency for alpha decay. Advancing both cryogenic decay energy spectrometry (DES) and drop-on-demand inkjet metrology, a solution of Am-241 was assayed for massic activity (of order 100 kBq/g) with a relative combined standard uncertainty less than 1 %. We implement live-timed counting, spectroscopic analysis, validation by liquid scintillation (LS) counting, and confirmation of quantitative solution transfer. Experimental DES spectra are well modeled with a Monte Carlo simulation. The model was further used to simulate Pu-238 and Pu-240 impurities, calculate detection limits, and demonstrate the potential for tracer-free multi-nuclide analysis, which will be valuable for new cancer therapeutics based on decay chains, Standard Reference Materials (SRMs) containing impurities, and more widely in nuclear energy, environmental monitoring, security, and forensics.
Fitzgerald, R.
, Alpert, B.
, Bergeron, D.
, Carlson, M.
, Essex, R.
, Morgan, K.
, Muramoto, S.
, Nour, S.
, O'Neil, G.
, Schmidt, D.
, Shaw, G.
, Swetz, D.
and Verkouteren, R.
(2025),
Primary activity measurement of an Am-241 solution using microgram inkjet gravimetry and decay energy spectrometry, Metrologia, [online], https://doi.org/10.1088/1681-7575/adecaa, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958017
(Accessed October 9, 2025)