Development of focusing supermirors by means of ion beam sputtering and ultra-precise figuring techniques

超精密表面創成とイオンビームスパッタ法による中性子スーパーミラーの開発

山崎 大  ; 丸山 龍治   ; 春日井 好己  ; 原田 正英   ; 曽山 和彦  ; 林田 洋寿*; 永野 幹典*; 田畑 雄壮*; 光嶋 直樹*; 山村 和也*

Yamazaki, Dai; Maruyama, Ryuji; Kasugai, Yoshimi; Harada, Masahide; Soyama, Kazuhiko; Hayashida, Hirotoshi*; Nagano, Mikinori*; Tabata, Takaaki*; Mitsushima, Naoki*; Yamamura, Kazuya*

数値制御ローカルウェットエッチング法による超精密基板加工法と高性能スーパーミラー成膜による非球面スーパーミラーを開発している。400mmの長尺楕円基板にm=4スーパーミラーを成膜することで1次元楕円スーパーミラーを製作し0.128mmの集光幅、集光ゲイン52を達成した。また、2次元集光を目的としてK-Bミラー配置を構築することで0.5mm径の集光に成功した。

We have been developing focusing supermirrors by depositing a supermirror on a precisely figured aspheric surface. Surface of a quartz substrate is figured using the "numerically-controlled local wet etching" technique. The figured surface shows a figure error of less than 1 micrometer p-v and an RMS roughness of less than 0.2 nm. Deposition of NiC/Ti supermirror (m=4) with ion beam sputtering keeps the figure error within several micrometers p-v and the roughness almost unchanged. A one-dimensional elliptical supermirror of 400mm in length was developed and it successfully achieved focused peak width (FWHM) of 0.128 mm and peak intensity 52 times that of unfocused (divergent) beam. We also tried two-dimensional focusing using two (vertical and lateral) focusing mirrors in a Kirkpatric-Baez configuration and successfully focused the beam to a spot of 0.5 mm in diameter.