Isotope shift and hyperfine structure measurements at the242f Am fission isomer

1996

Istope shift and hyperfine structure measurements have been performed for the242fAm fission isomer with target production rates of only a few per second. The method is based on resonance ionization spectroscopy (RIS) in a buffer gas cell with radioactive decay detection of the ionization process (RADRIS). A relative isotope shift ratioX exp=IS242f,241/ IS243,241=41.7±0.9 has been measured for the 500.02 nm transition corresponding to a nuclear parameter Λ242f,241=5.4±0.3 fm2. The analysis of the quadrupole moment based on the deformed Fermi-model of the nuclear charge distribution including second order corrections results inQ 20=38.2 ±1.4( −0.8 +0.4 )model eb. The measurement of the hyperf…