Enhancing the energy resolution of resonant coherent excitation using the cooled U89+ beam extracted from the ESR

We report on the resonant coherent excitation (RCE) of the 2s-2p3/2 transition in Li-like U89+ with an enhanced energy resolution, which was achieved by reducing the projectiles momentum spread. The kinetic temperature of the beam was decreased by electron cooling in the ESR, and the collisional momentum broadening in the target was suppressed by the use of thin crystal (1.0 and 2.5 μm-thick). The resonance width was observed to be ~1.4 eV in FWHM, which is three-times narrower than that from the previous work.