CRIS471: Combining laser and decay spectroscopy to study neutron-deficient francium

Kara Marie Lynch, Bruce Marsh, Gerda Neyens, Hanne Heylen, Hinko Henry Stroke, Ilya Strashnov, Ivan Budincevic, Jonathan Billowes, Kieran Flanagan, Klaus Wendt, Mark Bissell, Ralf Erik Rossel, Ronald Fernando Garcia Ruiz, Ruben Pieter De Groote, Sebastian Rothe, Serge Franchoo, Thomas Elias Cocolios, Valentine Fedosseev

Research output: Contribution to conferencePosterpeer-review


The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE uses laser radiation to stepwise excite and ionize an atomic beam for the purpose of ultra-sensitive detection of rare isotopes, and hyperfine structure measurements. The resonance ionization technique offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars (including the ground state of an isotope from its isomer) allowing decay spectroscopy to be performed.

Laser assisted nuclear decay spectroscopy is a novel technique developed at CRIS to selectively ionize nuclear ground or isomeric states present in the ISOLDE beam for radioactive-decay measurements on pure states. The isomeric ion beam is selected using a resonance of its hyperfine structure, where it is deflected to a decay spectroscopy station (DSS). This consists of a rotating wheel implantation system for alpha-decay spectroscopy, and up to three germanium detectors around the carbon-foil implantation site for gamma-ray detection. The ability of CRIS to alpha-tag the hyperfine components of overlapping structures allows the hyperfine structure of two (or more) states to be separated.

Last year, collinear resonance ionization spectroscopy and laser assisted nuclear decay spectroscopy
were performed on the neutron-deficient francium isotopes 202-207Fr. This allowed the identification of the hyperfine components of the low-lying states of 202Fr and 204Fr with alpha-spectroscopy.
Here, we present the hyperfine-structure and radioactive-decay studies from the IS471 experiment
campaign, alongside a brief overview of the CRIS beam line and the DSS.
Original languageEnglish
Publication statusPublished - 25 Nov 2013
EventIsolde Workshop and Users meeting 2013 - The Globe, CERN, Zurich, Switzerland
Duration: 25 Nov 201327 Nov 2013


ConferenceIsolde Workshop and Users meeting 2013
Internet address


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