An advanced experiment has been performed to improve X-ray laser output in the recombination plasma scheme. Two 11-mm-long plasmas were produced by laser irradiation so that each axis aligned into a line consisting the double-target configuration. X-ray intensity of the 15.47 nm transition line of the Li-like Al ion was enhanced in the double-target scheme. A half-cavity experiment in the double-target configuration was also performed, and the enhancement of X-ray was also observed. The results in the half-cavity experiment were consistent with an estimation, where the two plasmas having positive gain contribute to amplify X-rays passing through plasmas and reflecting from the multilayer mirror. Measurements have been started to clarify spatial coherence of the lasing X-ray beam by using the dispersing coherent diagnostic system.
Review of the soft-X-ray laser research at CEL-V