Soft X-ray optics characterization on SURF II

Abstract

We describe the present capabilities and future plans for soft X-ray optics characterization at the NIST storage ring, SURF II. The existing facility is made up of a monochromator and a reflectometer capable of characterizing the reflectivity of soft X-ray devices, including multilayers, gratings and grazing incidence optics. This system can also be used to characterize the transmission of components such as filters. The present capabilities include a wavelength range from 80 Å to 600 Å. The reflectometer will handle components up to several cm in diameter and its detector can be scanned in two independent angular directions. This allows the mapping of scattered photons from the sample, as well as the measurement of reflectivity as a function of angle and wavelength. Results of measurements on users' samples will be shown. We plan to modernize and expand the capabilities of this facility in the following ways: (1) Construct a new monochromator capable of scanning wavelengths from 30 Å to greater than 600 Å. (2) Construct a new reflectometer with independent, computer-controlled angular and translational motion for the sample and detector. This will permit automated wavelength scans and Θ/2Θ scans at fixed wavelengths, as well as mapping of the sample surface. The reflectometer will have a multidetector capability. It will also allow the measurement of optical constants of thin films. (3) Construct an optical test bench for characterizing the imaging properties of focusing optics. Other considerations for expanded capabilities, depending on the needs of the soft X-ray user community, include: (1) In-situ deposition of thin films with a vacuum transfer capability. (2) Provisions for other types of characterization, such as scanning tunneling microscopy (STM) and interferometric profilometry.

<title>XUV polarimeter for undulator radiation measurements</title>

“…Spectral reflectivity measurements of the polarizers were performed at the SURF II beamline at NIST. 13 The results for two of the polarizers are shown superimposed with measurements of the undulator spectra in Fig. 5.…”

XUV characterization comparison of Mo/Si multilayer coatings

“…The SURF II storage ring at NIST was used with a grazing-incidence grating monochromator and transmission filters to measure reflectance versus wavelength [8], with the incidence angle fixed to 10 degrees. Intensity measurements were made with a silicon photodiode, and were normalized to variations in the storage ring electron beam current by monitoring the flux incident to the monochromator.…”

“…The upper plot shows the measured and calculated reflectance versus incidence angle data at three wavelengths, while the lower plot shows the measured and calculated reflectance versus wavelength data. Best-fit calculated reflectances were computed using the optical constants from reference {11].1 Instrumental spectral resolutions were included in the calculations, and in the case of the NIST data, where the beam is highly polarized, the estimated incident beam polarization was also included [8]. For the Sandia laser-plasma measurements, a constant background (of order 5%) was subtracted from the data, to account for scattered light in this system.…”

Reversible structural phase transitions in semiconductor and metal/semiconductor surfaces

“…Angle-resolved photoemission data were not conclusive [31]. Early energy-minimization calculations showed that buckled dimers were more stable [32], although total-energy calculations indicated that symmetric and asymmetric models had very similar energies at RT [33]. Ihm et al [25] performed total-energy calculations combined with position-space renormalization-group calculations to obtain predictions of the structural phase transitions of the Si(100) surface as a function of temperature.…”