ANALYSIS AND DESIGN OF A NEW KIRKPATRICK-BAEZ MIRROR SYSTEM FOR MICROBEAMS

摘要

The 4B beamline of Pohang Accelerator Laboratory is used for microdiffraction and microfluorescence experiments using an X-ray microbeam. The X-ray microbeam has been focused down to 3 μm × 3 μm using a Kirkpatrick-Baez (K-B) mirror system with vertically and horizontally focusing mirrors arranged in series. In this research, a new K-B mirror system was developed for focusing a microbeam to 1 μm × 1 μm at the 4B beamline of the Pohang Light Source-II. The new K-B mirror system consists of a pair of assemblage having three mechanisms that adjust the position, pitch, and curvature of each vertically and horizontally focusing mirrors and stages that support both the assemblages to enable translations along two orthogonal axes and rotation on the horizontal plane. Both the pitch- and curvature-adjusting mechanisms were designed as flexural mechanisms driven by their respective single actuators to minimize the movement of the mirror center even when the pitch or the curvature of each mirror was adjusted. The K-B mirror system with these features will be robust against possible disturbances and will help promote easy and simple mirror adjustment. This paper describes the whole design of the new K-B mirror system in detail and the structural analysis results of the pitch- and the curvature-adjusting mechanisms, and reports the operation principle of the curvature-adjusting mechanism.