Multiphoton induced x-ray emission from Kr clusters onM-shell (∼100 Å) andL-shell (∼6 Å) transitions

Experiments demonstrating the role of cluster formation on multiphoton-induced x-ray emission and the scaling of this phenomenon into the kilovolt range have been performed on Kr. For the Kr M shell, augmentation of Krₙ formation leads to a large increase in Kr⁹⁺ (4p{→}3d) emission ({~}100 {}) and the appearance of a strong band at {~}90 {}. The observation of L-shell transitions ({~}5--7.5 {}) demonstrates the scaling of this phenomenon into the kilovolt region and leads to the conclusion that the interaction produces direct inner-shell excitation with the emission of prompt x rays.