title: Standardization of ²³⁷Np.
abstract: The standardization of (237)Np was investigated. The certified massic activity for (237)Np was obtained by 4παβ liquid scintillation (LS) counting with correction for the (233)Pa daughter using the CIEMAT/NIST efficiency tracing method using a (3)H standard. Confirmatory measurements were also performed by high-resolution HPGe gamma-ray spectrometry, and by 4παβ(LS)-γ(NaI) anticoincidence counting. All results agree within the respective method's uncertainties. It was confirmed that the (237)Np/(233)Pa radioactive equilibrium is disturbed when making dilutions and/or removing aliquots.
authors.affiliation: Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8462, USA. Electronic address: lizbeth.laureano-perez@nist.gov.
authors.forename: Lizbeth
authors.initials: L
authors.lastname: Laureano-Perez
authors.affiliation: Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8462, USA.
authors.forename: R
authors.initials: R
authors.lastname: Fitzgerald
authors.affiliation: Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8462, USA.
authors.forename: R
authors.initials: R
authors.lastname: Collé
keywords: Anticoincidence counting; Efficiency tracing; Liquid scintillation (LS); Neptunium-237; Radioactivity; SRM