Measurement of the (1s) Lamb shift of hydrogen-like krypton

Abstract
The absolute energy of the Lyman- alpha 1 line of hydrogen-like krypton has been measured with an accuracy of 36 p.p.m. The ions were produced at GANIL (Caen) and the X-rays emitted in flight detected with a flat crystal spectrometer. The (1s) Lamb shift of hydrogen-like krypton has been found to be 11.95+or-0.5 eV in good agreement with theory.