Figure 1
Schematic of the jth scan of the in situ pencil-beam procedure as implemented at Diamond Light Source for bimorph mirrors. A small slit upstream from the mirror illuminates the ith section of the mirror's surface. A total of m slit positions are scanned. Of the bimorph mirror's n electrodes, electrodes 1 to j − 1 have been incremented. The centroid yij of the beam reflected from the ith section of the mirror during the jth scan is calculated from the image recorded by the camera. For mechanical mirrors the principle is the same, except that instead of electrodes there are mechanical actuators. |