| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an X-ray irradiation device or an exposing method capable of measuring the polluted state on X-ray optical elements, and also capable of knowing the necessity of replacement or cleaning of the X-ray optical elements. SOLUTION: The measuring device is such a one that optical elements 23, 25 are irradiated with electromagnetic waves or electron beams for measuring the pollution of the optical elements 23, 25. In this case, measuring means 3a, 3b are provided for detecting the electron discharged from the optical elements 23, 25, selecting the electrons in a prescribed energy range out of the detected electrons, and measuring the electrons within the selected energy range.</p> |
