Lamb-shift measurement in hydrogenlike Sulfur

Abstract

The 2S 1/2-2P 1/2 Lamb-shift in hydrogenlike Sulfur was measured with a field quench technique. A high velocity beam of S15+-ions (v/c=0.086) prepared in the metastable 2S 1/2 state crosses a homogeneous magnetic field of about 1.8 Tesla. The strong electric field of 4·107 V/m in the rest frame of the ions mixes the longlived 2S 1/2-state (τ=7.18 nsec) with the short lived 2P 1/2-state (τ=2.4·10−5 ns). From the measured lifetime of the thus quenched 2S 1/2-state a Lamb-shift value of 25.14±0.24 THz is derived and compared with theoretical predictions.