Measurements of nuclear parameters of high-Z isotopes performed on a high-energy electron beam ion trap

Abstract

Spectral measurements of highly charged ions have been performed on the Livermore high-energy electron beam ion trap (EBIT) for determining various nuclear parameters. A value of μ = 4.1267 μ N was inferred for the nuclear magnetic moment from a measurement of the hyperfine transition of 165Ho 66+ in the visible. Values of δ〈 r 2〉 233,238 = −0.432 fm 2 and δ〈 r 2〉 235,238 = −0.250 fm 2 were determined for the isotopic variation of the nuclear charge radius from the energy shift of L-shell transitions in 233 U q+ and 235 U q+ relative to the x-ray line emission from 238 U q+ ions, with q = 86, 87, 88, 89. The accuracy of these measurements equals or exceeds that of earlier measurements relying on different techniques, because the atomic structure of highly charged ions is greatly simplified compared to that of neutral or few-times charged ions. The measurements can be extended to a variety of isotopes from hydrogen to transuranic elements. The latter was demonstrated in the first production of highly charged 249Cf ions in the trap.