The new beamline ALOISA, now operational at the Elettra Synchrotron, is designed for surface studies by means of several experimental techniques: surface x-ray diffraction and reflectivity, photoemission spectroscopy, photoelectron diffraction, e−-Auger coincidence spectroscopy. A new monochromator has been specifically designed and realized for this multipurpose beamline: it makes use of a channel-cut Si crystal dispersive element for the 3–8 keV range and of a plane mirror-plane grating element for the 200–2000 eV range. Both dispersive elements share the same optical system. In the low energy range (200–900 eV) the spectral resolving power exceeds 5000 while maintaining a throughput higher than 1010 photons/s/200 mA/0.02% BW. In the case of the N2 1s→π* and Ne 1s→3p transitions, the extremely high signal-to-noise ratio of the absorption spectra allowed a very accurate determination of the corresponding natural linewidth (116±2 and 250±10 eV, respectively). Moreover, the vibrational structure of the CO–...

Performance of the grating-crystal monochromator of the ALOISA beamline at the Elettra Synchrotron

We review the development of a number of soft-X-ray spectromicroscopes at synchrotron radiation facilities throughout the world. These instruments make use of several different technical approaches to achieve lateral resolution. Each approach has advantages and limitations, which makes the different instruments largely complementary to each other. These exciting new devices make full use of the high brightness of present synchrotron radiation sources and fully justify the current development of new ultrabright sources.

Overview of soft-x-ray photoemission spectromicroscopy

This report presents a modification of an SX700 plane grating monochromator, which can be made to work stigmatically by introducing an entrance slit. It will then provide the highest possible photon density in the exit slit with resolving powers that can be very high because it is not any longer source‐size limited. Instead it can be adjusted according to the slit settings. The deterioration of the resolving power because of slope errors in the ellipsoid can be avoided by orienting this mirror for sagittal focusing in the grating dispersion plane. In this configuration the instrument can be matched almost ideally to undulator sources.

Soft x‐ray monochromator configurations for the ELETTRA undulators: A stigmatic SX700 (invited)

The optical configuration of the monochromator for the new beamline X-MOSS at the ELETTRA synchrotron ring is described The requirements for this instrument are to collect a 3 mrad X 2 mrad aperture beam produced by a bending magnet in the 3 - 1400 eV energy range; the energy resolution has to be 3000 or better over the whole range, with a focused beam of the order of 10 - 50 micrometer The designed monochromator, presently under construction, is a slitless four grazing incidence optical elements: the first element is a one-meter paraboloidal mirror in sagittal focusing, then there is a plane mirror-plane grating dispersion system and finally a second one-meter paraboloidal mirror, also used in sagittal focusing The latter focuses the radiation on the monochromator exit slit This monochromator design is not limited by a defined working curve: in this way it is possible to select the preferred operational parameters, to optimize either the flux or the resolution or the high order rejection The monochromatic beam is finally sent on the sample under examination by an ellipsoidal refocusing mirror

Monochromator for the synchrotron radiation beamline X-MOSS at ELETTRA

A new configuration for a wide ultraviolet range high resolution monochromator has been analysed. It consists of a first off-axis paraboloidal mirror collimating the radiation beam from the source, followed by a couple of plane optical elements, a mirror and a grating, constituting the dispersive system, and by a second off-axis paraboloidal mirror focusing a selected portion of the dispersed radiation beam on a fixed exit slit. Since in the extreme ultraviolet region it is necessary to use the optical elements in grazing incidence to have a good reflectivity, the two paraboloidal mirrors can be used in the so-called sagittal focusing to minimize the slope error induced aberrations in the dispersive plane. As an example, the monochromator performances when applied to a synchrotron radiation source in the range 250-1250 eV (9.9-49.6 AA) are shown.

http://iopscience.iop.org/article/10.1088/0963-9659/1/6/007/pdf

A high resolution monochromator covering wide ultraviolet spectral ranges with a single grating

At BESSY a beamline for applications in laterally resolved photoelectron-spectroscopy is planned. The performance of such a small spot scanning ESCA line (ESCAN) using synchrotron radiation is described. In the present design a combination of a stigmatically focussing SX-700 type plane grating monochromator and a zone plate create a microspot of less than 5 μm in diameter. The flux concentrated in that spot should make small spot ESCA possible even with synchrotron radiation from dipole magnets.

D. Rudolph

Papers

Possibility of Spatially Resolved Synchrotron Radiation Spectroscopies Using a Stigmatically Focussing Monochromator