The ideal shape for a mirror to focus X-rays from a point source is ellipsoidal. A KB mirror is a 2D focusing optical system using two elliptical mirrors with vertical and horizontal working directions. An ellipsoidal mirror enables 2D focusing using a mirror that has a 2D shape on its optical surface.
In comparison with a KB mirror, which requires two reflections, an ellipsoidal mirror needs only one reflection; thus, its focusing efficiency is higher. In addition, because there is no vertical reflection, users can easily adjust the settings of the optical system. On the other hand, ellipsoidal mirrors have shapes with steep curvature, especially in a direction sagittal to the incident X-rays. It is much more difficult to measure such mirror shapes with high accuracy, in comparison with other mirrors.
JTEC has developed 3D shape measuring equipment that can measure with high accuracy even shapes with steep curvature. We have realized high-precision ellipsoidal mirrors and delivered them to major synchrotron radiation facilities.