The 1s Lamb shift of hydrogen-like very heavy ions measured at an electron cooler

Abstract

Spontaneous capture of free cooling electrons by bare high-Z ions leads to the emission of X rays. The distinctive features of this new X-ray source for precision spectroscopy of high-Z few-electron systems are demonstrated. They enable a determination of the Lamb shift of hydrogen-like very heavy ions. Initial experiments have been conducted at the GSI Experimental Storage Ring in which the 1s Lamb shift has been found to be 202.3/spl plusmn/7.9 eV for Au/sup 78+/ and 470/spl plusmn/16 eV for U/sup 91+/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>