Stigmatic high-resolution high-throughput narrowband diffraction spectrograph employing multilayer mirrors

摘要

A novel diffraction spectroscopic instrument comprising two focusing multilayer mirrors (MMs) at near-normal incidence and a conventional blazed plane grating at grazing incidence has been implemented. A nearly perfect stigmatism and a theoretical resolving power above 6 $MUL 10$+4$/ are due to the separation of the focusing and dispersing functions. For higher throughput, MMs with nearly identical resonance reflection curves around $lambda$-0$/ $APEQ 135 angstroms have been synthesized employing a magnetron ion sputtering source. The instrument performance has been assessed using a laser-plasma XUV radiation source. The spectral resolution in excess of 4 $MUL 10$+3$/ and the applicability to space-resolved spectroscopy and plasma diagnosis have been demonstrated.