title: Conversion electron spectrometry of Pu isotopes with a silicon drift detector.
abstract: An electron spectrometry set-up was built at IRMM consisting of a vacuum chamber with a moveable source holder and windowless Peltier-cooled silicon drift detector (SDD). The SDD is well suited for measuring low-energy x rays and electrons emitted from thin radioactive sources with low self-absorption. The attainable energy resolution is better than 0.5keV for electrons of 30keV. It has been used to measure the conversion electron spectra of three plutonium isotopes, i.e. (238)Pu, (239)Pu, (240)Pu, as well as (241)Am (being a decay product of (241)Pu). The obtained mixed x-ray and electron spectra are compared with spectra obtained with a close-geometry set-up using another SDD in STUK and spectra measured with a Si(Li) detector at IRMM. The potential of conversion electron spectrometry for isotopic analysis of mixed plutonium samples is investigated. With respect to the (240)Pu/(239)Pu isotopic ratio, the conversion electron peaks of both isotopes are more clearly separated than their largely overlapping peaks in alpha spectra.
authors.affiliation: European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel, Belgium. Electronic address: stefaan.pomme@ec.europa.eu.
authors.forename: S
authors.initials: S
authors.lastname: Pommé
authors.affiliation: European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Paepen
authors.affiliation: STUK-Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Peräjärvi
authors.affiliation: STUK-Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Turunen
authors.affiliation: STUK-Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Pöllänen
keywords: Isotopic ratio; Nuclear security; Plutonium; Safeguards; Silicon drift detector