Stacking mirror device using millimeter-thick elliptical supermirrors fabricated by numerically controlled local wet etching for focusing neutron beam

摘要

Stack of millimeter-thick aspherical supermirror enables us to focus neutron beams with wide divergence. We applied noncontact figuring by the numerically controlled local wet etching technique and fabricated elliptical mirror substrate with a thickness of 1 mm. Figure error of 0.29 μm p-v was obtained. In addition to the figure error, an alignment error of the mirrors is the main factor influencing focusing performance. An alignment device, which support 4 thin mirrors by independent three points respectively, was developed to satisfy the calculated alignment tolerance.