Prediction and Optimization of Thickness Distribution in the Electroforming Process for X-Ray Astronomical Telescopes

抄録

X-ray astronomical telescopes with higher angular resolution are required for future astronomical missions. To achieve a high spatial resolution below 10 arcseconds, high figure accuracy is required for the Wolter mirror, which serves as the focusing element. In this study, we aimed to improve the figure accuracy of Ni-electroformed mirrors by achieving uniform film thickness during electrodeposition. An electrodeposition simulation using the finite element method (FEM) was developed to predict thickness distributions. The simulation reveals that placing shields around the mirror is an effective method to suppress current concentration at the edges. We experimentally confirm that this approach improves the uniformity of the thickness distribution in the electrodeposited film, leading to an increase in the figure accuracy of the Wolter mirror.