Progress at the Heidelberg EBIT

Abstract

Two years after the relocation of the Heidelberg EBIT, several experiments are alreadyin operation. Spectroscopic measurements in the optical region have delivered the most precisereported wavelengths for highly charged ions, in the case of the forbidden transitions of Ar XIV andAr XV. The lifetimes of the metastable levels involved in those transitions has been determined withan error of less than 0.2%. A new, fully automatized x-ray crystal spectrometer allows systematicmeasurements with very high precision and reproducibility. Absolute measurements of the Lymanseries of H-like ions are currently underway. Dielectronic recombination studies have yieldedinformation on rare processes, as two-electron-one photon transitions in Ar16+, or the interferenceeffects between dielectronic and radiative recombination in Hg77+. The apparatus can now operateat electron beam currents of more than 500 mA, and energies up to 100 keV. A further beam energyincrease is planned in the near future. Ions can be extracted from the trap and transported to externalexperiments. Up to 4 × 107 Ar16+ ions per second can be delivered to a 1 cm diameter target at 10 m distance. Charge-exchange experiments with U64+ colliding with a cold He atomic beam havebeen carried out, as well as experiments aiming at the optimization of the charge state distributionof the extracted via dielectronic recombination. Two new EBITs, currently in advanced state ofconstruction in Heidelberg, will be used for experiments at the VUV free electron laser at TESLA(Hamburg) and for the charge breeding of short-lived radioactive isotopes at the TRIUMF ISACfacility.