Holographically recorded, ion etched varied line spacing plane grating for a monochromator at BL19B

Abstract

The difficulties were pointed out to lie in making a Varied line spacing Plane Gratings (VPG) for a BL19B type monochromator by means of a conventional holographic recording method. The reasons of the difficulties to make the gratings for BL19B type monochromator and the comparison with a grating made by a mechanical ruling method were discussed. A new holographic recording method has recently been developed, which enables one to make a large varied line coefficient. The relative estimation has been carried out for the stray light level and the efficiency of the holographically recorded ion etched ruling VPG by comparing to those of the mechanical ruling grating. Two spectra of the undulator radiation measured using the gratings made by the new holographic recording method and the mechanical ruling method were shown in figures. It was clarified that the stray light level, the efficiency at higher photon energy region, and the resolution of the grating made by the new holographic recording method are superior to that of the mechanical ruling grating.

BL19B型モノクロメータ用の可変線間隔平面格子を通常のホログラフ記録法を使って作製するには難しい問題があることを指摘した。BL19B型モノクロメータ用の格子を作製するのが困難な理由および機械的罫線法により作製した格子との比較を論じた。最近新規ホログラム記録法が開発され、線変動係数を大きくすることが可能となった。ホログラム記録イオンエッチング線VPGの迷光水準および効率を機械的罫線格子の迷光水準と効率と比較して相対評価を行った。新規ホログラム記録法と機械的罫線法を用いて作製した格子を使って測定した2種のアンジュレータ放射スペクトルを図に示した。新規ホログラム記録法を用いて作製した格子の迷光水準、高フォトンエネルギー領域における効率および分解能が機械的罫線格子のものよりも優れていることが明らかになった。