"Resonant Coherent Excitation of Highly-Charged Ions in Crystals", Friday, September 25, 12:00pm, MH 606
Alena Ananyeva, GSI Helmholtz Centre for Heavy Ion Research
ABSTRACT: The resonant coherent excitation of ions in the fast oscillating electrical field, with frequencies in the x-ray range, created by the periodic Coulomb potential of a crystal target is a phenomenon which holds a large potential for spectroscopic investigations in relativistic highly-charged ions. If the field frequency matches the energy difference between two electronic states, a resonant excitation of the ion became possible. The onset of the process can be steered by tuning the ion velocity by fix target orientation or the relative orientation of the incoming ion velocity and the crystallographic orientation. If the crystal orientation simultaneously permits frequencies for two different electronic transitions, a sequential resonant excitation to higher states becomes possible.
This contribution presents a series of experiments performed at GSI (Darmstadt, Germany) and HIMAC (Tokyo, Japan) facilities with relativistic beams of heavy ions and thin Silicon crystal-targets. The occurrence of the ions excitation was detected by measuring the charge-state distribution of the ions after the interaction with the crystal and the yield of the x-rays emitted during the decay of the excited states as a function of the relative orientation of the target to the beam direction.
The performed measurements clearly demonstrate that sequential 1s->2p->3s/3d electron transition in H-like Ar was experimentally observed together with the alignment of the magnetic substates of the ions by the polarised crystal field. Resonant coherent excitation was also successfully applied for a precision measurement of a 1s22s->1s22p3/2 electron transition in Li-like U.