The at wavelength metrology facility for UV and XUV reflection and diffraction optics at BESSY II

A technology center for the production of high precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at wavelength characterization of UV and XUV reflection gratings and other nano optical elements has been set up at BESSY II. The Plane Grating Monochromator beamline operated in collimated light c PGM is equipped with an SX700 monochromator, of which the blazed gratings 600 and 1200 lines mm 1 have been recently exchanged for new ones of improved performance produced in house. Over the operating range from 10 to 2000 eV this beamline has very high spectral purity achieved by i a four mirror arrangement of different coatings which can be inserted into the beam at different angles and ii by absorber filters for high order suppression. Stray light and scattered radiation is removed efficiently by double sets of in situ exchangeable apertures and slits. By use of in and off plane bending magnet radiation the beamline can be adjusted to either linear or elliptical polarization. One of the main features of a novel 11 axes reflectometer is the possibility to incorporate real life sized gratings. The samples are adjustable within six degrees of freedom by a newly developed UHV tripod system carrying a load up to 4 kg, and the reflectivity can be measured between 0 and 90 deg incidence angle for both s and p polarization geometry. This novel powerful metrology facility has gone into operation recently and is now open for external users. First results on optical performance and measurements on multilayer gratings will be presented her

Gratings for synchrotron and FEL beamlines a project for the manufacture of ultra precise gratings at Helmholtz Zentrum Berlin

Blazed gratings are of dedicated interest for the monochromatization of synchrotron radiation when a high photon flux is required, such as, for example, in resonant inelastic X ray scattering experiments or when the use of laminar gratings is excluded due to too high flux densities and expected damage, for example at free electron laser beamlines. Their availability became a bottleneck since the decommissioning of the grating manufacture facility at Carl Zeiss in Oberkochen. To resolve this situation a new technological laboratory was established at the Helmholtz Zentrum Berlin, including instrumentation from Carl Zeiss. Besides the upgraded ZEISS equipment, an advanced grating production line has been developed, including a new ultra precise ruling machine, ion etching technology as well as laser interference lithography. While the old ZEISS ruling machine GTM 6 allows ruling for a grating length up to 170 mm, the new GTM 24 will have the capacity for 600 mm 24 inch gratings with groove densities between 50 lines mm 1 and 1200 lines mm 1. A new ion etching machine with a scanning radiofrequency excited ion beam HF source allows gratings to be etched into substrates of up to 500 mm length. For a final at wavelength characterization, a new reflectometer at a new Optics beamline at the BESSY II storage ring is under operation. This paper reports on the status of the grating fabrication, the measured quality of fabricated items by ex situ and in situ metrology, and future development goal

Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X ray free electron laser

Abstract The Linac Coherent Light Source LCLS is upgrading the machine to high repetition rate and to extended ranges. Novel coatings, with limited surface oxidation, which are able to work at the carbon edge, are required. In addition, high resolution soft X ray monochromators become necessary. One of the big challenges is to design the mirror geometry and the grating profile that have high reflectivity or efficiency and at the same time can survive the high peak energy of the FEL pulses. For these reasons, we investigated the experimental damage threshold, at 900 eV, of two platinum coated gratings with different blazed angles. The gratings were tested at 1o grazing incidence. To validate a model for which the damage threshold on blaze grating can be estimated by calculating the damage threshold of a mirror with an angle of incidence identical to the angle of incidence on the grating plus the blaze angle, tests on Pt coated substrates have also been performed. The results confirmed the prediction. We also investigated uncoated silicon, platinum and SiB3 both deposited on a silicon substrate . In general, the measured damage threshold at the grazing incidence is higher than calculated under the assumption that there is no energy transport from the volume where the photons are absorbed. However, we found that for the case of SiB3 coating, the grazing incidence condition did not increase the damage threshold indicating that the energy transport away from the extinction volume is negligibl