Advanced metrology: an essential support for the surface finishing of high performance x-ray optics

Siewert, Frank; Lammert, Heiner; Noll, T.; Schlegel, Thomas; Zeschke, Thomas; Hänsel, T.; Nickel, Andreas; Schindler, Axel; Grubert, Bernd; Schlewitt, Carsten

doi:10.1117/12.622747

Cited by 39 publications

(41 citation statements)

References 5 publications

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“…In this case incoming and diffracted higher order beam described by P and & are in coincidence as shown in equation (1), with n for the diffraction order used [6,7].…”

Section: Inspection Of Groove Densitymentioning

confidence: 99%

“…To validate the achieved measurement accuracy, the values obtained with the NOM have been crosschecked with other high precision metrology instruments like the ESAD method [5]. The NOM allows to measure optical components with an estimated measurement uncertainty in the range of 0.05urad rms [3,6]. In general it is to consider that the uncertainty budget is to be estimated individually for each measurement.…”

Section: The Nano Optic Measuring Machine -Nommentioning

confidence: 99%

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Inspection of a Spherical Triple VLS-Grating for Self-Seeding of FLASH at DESY

Siewert¹,

Lammert²,

Reichardt³

et al. 2007

AIP Conference Proceedings

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Abstract. To take benefit from the improved brilliance of the laser-like source, proposed beamlines at Free Electron Lasers (FEL) require optical elements of excellent precision, characterised by slope errors beyond the state of the art limit of 0.5urad rms for plane and spherical shape. Part of the monochromator beamline for self-seeding at the vacuumultraviolet Free Electron Laser (FLASH) at DESY is a triple Variable Line Spacing (VLS) grating of spherical shape. The three grating structures on a common substrate will cover the wavelength range from 6.4 to 60nm. The challenging specifications of these grating structures are characterised by a slope error of less than 0.25urad rms and very stringent parameters for the VLS-polynomial [1]. These grating structures have been measured by use of the Nano Optic Measuring Machine (NOM) at BESSY. Based on the principle of deflectometry the BESSY-NOM [2,3] represents the latest generation of slope measuring metrology instruments. The NOM enables the inspection of optical components with a measurement uncertainty in the range of 0.05urad rms. This is a five to tenfold improvement compared to state of the art metrology tools of today. Here it is demonstrated how these outstanding metrology capabilities have been applied for a sound characterisation of a challenging precision optical component with error limits five times below the specifications. In the shown example the grating's figure accuracy has been characterised by linescans and surface mapping measurements of the optical active sections. In additional measurements under Littrow condition the higher order diffraction signals of the laser pencil beam have been traced to measure the groove density variation of the different grating-structures with a lateral resolution of 1mm. In contrast to the sparse and point like measurements of the manufacturer, these high resolution measurements yield a "slope deviation equivalent" resulting from imperfections in the line density variation.

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“…In this case incoming and diffracted higher order beam described by P and & are in coincidence as shown in equation (1), with n for the diffraction order used [6,7].…”

Section: Inspection Of Groove Densitymentioning

confidence: 99%

Section: The Nano Optic Measuring Machine -Nommentioning

confidence: 99%

Inspection of a Spherical Triple VLS-Grating for Self-Seeding of FLASH at DESY

Siewert¹,

Lammert²,

Reichardt³

et al. 2007

AIP Conference Proceedings

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“…1(a) shows a twodimensional slope map and the center line in the meridional direction of a state-of-the-art blank for a plane grating; it has a residual slope error of 150 nrad r.m.s., a micro-roughness of < 0.2 nm r.m.s. and a meridional radius of >500 km as measured by slope mapping with the BESSY-NOM (Siewert et al, 2005(Siewert et al, , 2011. The surface topography is obtained by integration of the slope data (Fig.…”

Section: Ex Situ Characterization Of Grating Blanks and Gratingsmentioning

confidence: 99%

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

et al. 2018

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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 À1 and 1200 lines mm À1. 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 goals.

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“…The best performing profilers like HBZ/BESSY-II NOM [5][6][7][8] have a movable mirror based pentaprism [19][20][22][23] and an autocollimator (AC) as a sensor [5,24]. Accuracy of the instruments is based on high precision calibration of the ACs for small apertures of 2.5 -5 mm [25][26].…”

Section: Osms Working Meetingsmentioning

confidence: 99%

“…The best profilers, such as the NOM at Helmholtz Zentrum Berlin (HZB)/BESSY-II [5][6][7][8] and at the Diamond Light Source [9], the ESAD instrument at the PTB [10][11][12], DLTP at the ALS [13], and upgraded LTPs at the ALS [14][15] and SPRING-8 [16], come close to the requirements. Most are based on a careful optomechanical design, and operate in exceptional environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Development of a new generation of optical slope measuring profiler

Yashchuk¹,

Takacs²,

McKinney³

et al. 2011

Nuclear Instruments and Methods in Physics Research Section A:

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A collaboration, including all DOE synchrotron labs, industrial vendors of x-ray optics, and with active participation of the HBZ-BESSY-II optics group has been established to work together on a new slope measuring profiler -the optical slope measuring system (OSMS). The slope measurement accuracy of the instrument is expected to be <50 nrad for the current and future metrology of x-ray optics for the next generation of light sources. The goals were to solidify a design that meets the needs of mirror specifications and also be affordable; and to create a common specification for fabrication of a multi-functional translation/scanning (MFTS) system for the OSMS. This was accomplished by two collaborative meetings at the ALS (March 26, 2010) and at the APS (May 6, 2010).

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Advanced metrology: an essential support for the surface finishing of high performance x-ray optics

Cited by 39 publications

References 5 publications

Inspection of a Spherical Triple VLS-Grating for Self-Seeding of FLASH at DESY

Inspection of a Spherical Triple VLS-Grating for Self-Seeding of FLASH at DESY

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

Development of a new generation of optical slope measuring profiler

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