Experimental progress in collisional x-ray laser development at ILE Osaka University

Experimental progress in Ne-like Ge x-ray lasers (19.6 nm and 23.6 nm) has been made by using a curved target and multiple-short pulse. The curved target was introduced to compensate x-ray laser beam refraction in a laser produced plasma. The pulse shape of the pumping laser was varied in search for the improvement in the pumping efficiency. For generation of shorter wavelength lasers, the scheme using a curved target pumped with a multiple-short pulse laser was extended to the amplification studies in Ni-like lanthanide elements (Nd, Sm, Gd, Tb and Dy) corresponding to the spectral range of 6 nm to 8 nm.