A high-flux 3-M normal incidence monochromator at beamline 20A of the Photon Factory

Abstract

A high-flux 3-m normal incidence monochromator (3-m NIM) has been installed at beam line 20A of the Photon Factory. The 3-m NIM can supply a high photon flux in the wavelength region 30–200 nm, primarily because of a large horizontal acceptance angle of 28 mrad for the synchrotron radiation (SR) beam from bending magnet 20. The photon flux of the 3-m NIM was estimated to be ≊1012 photons/s with Δλ≊0.1 nm at ≊50 nm by measuring the photoemission current from a gold-coated surface. The resolving power with a 2400 grooves/mm grating was found to be greater than 25 000 at 90 nm from the autoionization profile of the Xe nd′ states converging to Xe+ 2P1/2.