Preparation and research of freestanding Zr filter for soft X-ray laser

200 μg/cm2 free-standing Zr filters of 20 mm in diameter were made by DC magnetron sputtering. Soft X-ray spectral transmittance of the filters was measured in the National Synchrotron Radiation Laboratory, and the light blocking performance was tested by spectrophotometer. The elements in Zr filters were analyzed using Auger Electron Spectroscopy. The results indicate that Zr filters have good transmittance(19%) at 13.9 nm and perfect visible light blocking properties(43 dB), N，O arisen from background pressure, oxidation and surface contamination are the major species that affect the transmittance of Zr films in the soft X-ray．