title: Efficiency and resolution measurements of x-ray transmission gratings between 7.1 and 304 A.
abstract: Efficiency and resolution measurements are reported of an x-ray transmission grating to be flown on board the European X-ray Observatory Satellite (EXOSAT). By optimizing the thickness of the grating bars, very high efficiencies can be obtained over a limited energy range. An absolute efficiency of 20% at 7.1 A decreasing to 10% above 15 A has been achieved, including all effects of support structure and mounting necessary to withstand space qualification. This means that 10% of the incoming radiation at 7.1 A results in the minus first spectral order and 10% in the plus first order. The measured resolution at the short wavelength end of the range (lambda > 20 A) is determined by the mirror resolution; at the longer wavelengths (300 A), the effects of coma and astigmatism dominate. The measured resolution at 304 A for the EXOSAT-mirror-grating system is 4.5 A in agreement with theoretical predictions.
authors.forename: A C
authors.initials: AC
authors.lastname: Brinkman
authors.forename: J H
authors.initials: JH
authors.lastname: Dijkstra
authors.forename: W F
authors.initials: WF
authors.lastname: Geerlings
authors.forename: F A
authors.initials: FA
authors.lastname: van Rooijen
authors.forename: C
authors.initials: C
authors.lastname: Timmerman
authors.forename: P A
authors.initials: PA
authors.lastname: de Korte