title: Determination of the gamma emission intensities of ¹¹¹Ag.
abstract: A radioactive solution of (111)Ag, standardised by the absolute measurement methods 4π(PC)-γ and 4π(LS)-γ coincidence counting at the National Physical Laboratory (NPL), was measured by two independently calibrated HPGe γ spectrometers in order to estimate the γ emission intensities and to determine the absolute intensity, with the aim of improving the currently published values. An absolute intensity value of 6.68 (7)% was obtained for the 342.1 keV γ emission, which is in agreement with previously reported values, but greatly reduces the uncertainty. Additionally, this work proposes a new emission intensity for the 450.0 keV γ emission that has not been previously reported, with an absolute intensity of 0.000482 (12)%. An investigation of the published γ emission intensities shows significant discrepancies that require resolution.
authors.affiliation: National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom. Electronic address: smc1@npl.co.uk.
authors.forename: Sean
authors.initials: S
authors.lastname: Collins
authors.affiliation: National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Keightley
authors.affiliation: Atomic Weapons Establishment, Aldermaston, Reading, RG7 4PR, United Kingdom.
authors.forename: Chris
authors.initials: C
authors.lastname: Gilligan
authors.affiliation: National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom.
authors.forename: Joel
authors.initials: J
authors.lastname: Gasparro
authors.affiliation: National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom.
authors.forename: Andy
authors.initials: A
authors.lastname: Pearce
keywords: Ag-111; Gamma emission intensities; Radioactivity; Spectroscopy