SHAPE OF THE 2-PHOTON-CONTINUUM EMISSION FROM THE 1S2S(1)S(0) STATE IN HE-LIKE KRYPTON

We report a measurement of the spectral distribution of photons from t he two-photon decay of the 1s2s S-1(0) level in heliumlike krypton. In the experiment, a beam of Kr34+ ions was excited using a thin carbon foil and the two-photon decays were observed as coincidences in an arr ay of x-ray detectors. An important part of this work was the measurem ent of the efficiency of the detection system as a function of photon energy. A Monte Carlo model of the experiment was used to compare the data with theoretical calculations and demonstrated good agreement wit h the nonrelativistic calculations for 2=36.