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High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies.

Strocov VN, Schmitt T, Flechsig U, Schmidt T, Imhof A, Chen Q, Raabe J, Betemps R, Zimoch D, Krempasky J, Wang X, Grioni M, Piazzalunga A, Patthey L - J Synchrotron Radiat (2010)

Bottom Line: Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV.Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed.An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given.

View Article: PubMed Central - HTML - PubMed

Affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland. vladimir.strocov@psi.ch

ABSTRACT
The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 degrees rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/DeltaE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 microm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/DeltaE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given.

No MeSH data available.


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Experimental flux curves (solid lines) measured on the photodiode with 400 mA current in the ring, first harmonic of the LH polarized light and 20 µm exit slit, for the three gratings with flux-optimal C                  ff values (indicated on the right). The corresponding theoretical flux curves (dashed lines) are calculated for the same parameters. The experimental flux has potential for improvement with better alignment of the electron trajectories and UE44 magnetic lattice.
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fig9: Experimental flux curves (solid lines) measured on the photodiode with 400 mA current in the ring, first harmonic of the LH polarized light and 20 µm exit slit, for the three gratings with flux-optimal C ff values (indicated on the right). The corresponding theoretical flux curves (dashed lines) are calculated for the same parameters. The experimental flux has potential for improvement with better alignment of the electron trajectories and UE44 magnetic lattice.

Mentions: The theoretical flux was verified by measurements with a photodiode (AXUV100 from International Radiation Detectors) using the responsivity data from the manufacturer (available at http://www.ird-inc.com/). The diode was installed after the exit slit (before the refocusing optics). The beamline was operated with the nominal current in the ring of 400 mA, the first harmonic of the LH radiation, the flux-optimal C ff values for each grating, and the exit slit fixed to 20 µm (E/ΔE varying with energy). The measurements were performed after three years of regular beamline operation. The experimental flux curves are shown in Fig. 9 ▶ (solid lines) in comparison with theoretical ones (dashed lines) calculated with the same beamline set-up. Certain reduction of the experimental flux can be attributed, apart from imperfections of the optical elements and their accumulating contaminations, mainly to remnant misalignments of the electron trajectories and UE44 magnetic lattice (in fact, we could reach the experimental width of the undulator radiation peaks corresponding to some 55 periods rather than the physical 75) which can be improved in future. The larger flux reduction seen for the 4200 lines/mm grating, going along with about 70% inhomogeneity of efficiency observed along the optical surface, can be expected for a grating with a groove density close to the present technological limit. Our experimental flux performance can be compared with that of one of the worldwide best high-resolution soft X-ray beamlines, BL25SU at SPring-8 (Saitoh et al., 2000 ▶). For the same bandwidth corresponding to E/ΔE = 10000 (with the 800 lines/mm grating for ADRESS and 600 lines/mm for BL25SU) the flux delivered by the ADRESS beamline is better overall by a factor above 90, and for E/ΔE = 15000 (the 2000 lines/mm and 1000 lines/mm gratings, respectively) above 8.


High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies.

Strocov VN, Schmitt T, Flechsig U, Schmidt T, Imhof A, Chen Q, Raabe J, Betemps R, Zimoch D, Krempasky J, Wang X, Grioni M, Piazzalunga A, Patthey L - J Synchrotron Radiat (2010)

Experimental flux curves (solid lines) measured on the photodiode with 400 mA current in the ring, first harmonic of the LH polarized light and 20 µm exit slit, for the three gratings with flux-optimal C                  ff values (indicated on the right). The corresponding theoretical flux curves (dashed lines) are calculated for the same parameters. The experimental flux has potential for improvement with better alignment of the electron trajectories and UE44 magnetic lattice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2927903&req=5

fig9: Experimental flux curves (solid lines) measured on the photodiode with 400 mA current in the ring, first harmonic of the LH polarized light and 20 µm exit slit, for the three gratings with flux-optimal C ff values (indicated on the right). The corresponding theoretical flux curves (dashed lines) are calculated for the same parameters. The experimental flux has potential for improvement with better alignment of the electron trajectories and UE44 magnetic lattice.
Mentions: The theoretical flux was verified by measurements with a photodiode (AXUV100 from International Radiation Detectors) using the responsivity data from the manufacturer (available at http://www.ird-inc.com/). The diode was installed after the exit slit (before the refocusing optics). The beamline was operated with the nominal current in the ring of 400 mA, the first harmonic of the LH radiation, the flux-optimal C ff values for each grating, and the exit slit fixed to 20 µm (E/ΔE varying with energy). The measurements were performed after three years of regular beamline operation. The experimental flux curves are shown in Fig. 9 ▶ (solid lines) in comparison with theoretical ones (dashed lines) calculated with the same beamline set-up. Certain reduction of the experimental flux can be attributed, apart from imperfections of the optical elements and their accumulating contaminations, mainly to remnant misalignments of the electron trajectories and UE44 magnetic lattice (in fact, we could reach the experimental width of the undulator radiation peaks corresponding to some 55 periods rather than the physical 75) which can be improved in future. The larger flux reduction seen for the 4200 lines/mm grating, going along with about 70% inhomogeneity of efficiency observed along the optical surface, can be expected for a grating with a groove density close to the present technological limit. Our experimental flux performance can be compared with that of one of the worldwide best high-resolution soft X-ray beamlines, BL25SU at SPring-8 (Saitoh et al., 2000 ▶). For the same bandwidth corresponding to E/ΔE = 10000 (with the 800 lines/mm grating for ADRESS and 600 lines/mm for BL25SU) the flux delivered by the ADRESS beamline is better overall by a factor above 90, and for E/ΔE = 15000 (the 2000 lines/mm and 1000 lines/mm gratings, respectively) above 8.

Bottom Line: Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV.Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed.An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given.

View Article: PubMed Central - HTML - PubMed

Affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland. vladimir.strocov@psi.ch

ABSTRACT
The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 degrees rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/DeltaE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 microm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/DeltaE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given.

No MeSH data available.


Related in: MedlinePlus