Rami Sankari

On the characterization of ultra-precise X-ray optical components: advances and challenges in ex situ metrology.

State-of-the-art ex situ metrology for characterizing the quality of ultraprecise reflective synchrotron optics is reported. Beside slope measuring deflecometry the current state of mirror coating technology for single layer and multilayer coatings for very long mirror substrates is discussed.

The Normal Incidence Monochromator Beamline I3 on MAX III

On the 700 MeV MAX III ring at MAX‐lab, a 6.65 m off‐axis eagle type monochromator beamline has recently been commissioned. The beamline is sourced by an apple type variable polarization undulator. The energy range of the beamline is 4.6–50 eV and the resolving power achieved is more than 100,000. There are two branch lines, one for angle and spin resolved photoemission studies from solids and the other for gas phase and luminescence experiments. We present the design and performance of the beamline.

Description of the new I1011 beamline for magnetic measurements using synchrotron radiation at MAX-lab

We report on the characterization of the new I1011 beamline at the MAX-II storage ring, in the MAX-lab synchrotron radiation laboratory and give examples of first results. This beamline is using an Elliptically Polarizing Undulator source, producing soft x-rays of a variable polarization state. It delivers high flux and high brightness circularly polarized x-rays in the energy range 0.2 to 1.7 keV, covering the L-edges of the late 3d elements. The new beamline will operate with an octupole magnet endstation. It is specially engineered to solve the problem of the limited optical access typically associated with magnetic fields and synchrotron radiation endstations. Eight water-cooled magnets allow the application of the magnetic field of up to 1 T in any direction. X-ray absorption spectroscopy, X-ray resonant reflectivity and the corresponding magnetic variants, i.e., XMCD, XMLD and XRMS experiments are possible also under an applied magnetic field. The high flux allows working with dilute magnetic systems such as ultra-thin films and nano structures.

The SPECIES beamline at the MAX IV Laboratory: A facility for soft X-ray RIXS and APXPS

SPECIES, the soft X-ray beamline for resonant inelastic scattering and ambient-pressure photoelectron spectroscopy at MAX IV, is described.

FINEST:A high performance branch-line for VUV photon energy range gas phase studies at MAX-lab

We present a dedicated beamline branch for high flux and ultra-high resolution (R>100000) gas and vapor phase studies in the vacuum-ultra-violet (VUV) region of light on the undulator beamline I3, located on the 700 MeV MAX-III storage ring. The mechanical and optical design of the branch-line, the differential pumping setup as well as performance characteristics are presented.

Multilayer based soft-x-ray polarimeter at MAX IV Laboratory.

A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B4C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

Angle-resolved time-of-flight spectroscopy applied to multi-bunch operation at MAX-lab: a design study

Angle-resolved time-of-flight (ARTOF) spectrometers have found use in a number of applications, including ARPES. However, the fundamental requirement of an external start trigger matching the read-out time of the instrument limits its usability at many storage rings. Hitherto all reported experiments have been performed at storage rings capable of running in single-bunch mode. To eliminate this restriction, we propose a method where a pulsed electronic gate is introduced to allow for ARTOF usage at normal multi-bunch operation of the MAX II storage ring. This paper will show the working principle and outline the design for this technique.

A Tandem Time--of--Flight Spectrometer for Negative--Ion/Positive--Ion Coincidence Measurements with Soft X-ray Excitation

We present a newly constructed spectrometer for negative-ion/positive-ion coincidence spectroscopy of gaseous samples. The instrument consists of two time-of-flight ion spectrometers and a magnetic momentum filter for deflection of electrons. The instrument can measure double and triple coincidences between mass-resolved negative and positive ions with high detection efficiency. First results include identification of several negative-ion/positive-ion coincidence channels following inner-shell photoexcitation of sulfur hexafluoride (SF6).

Negative-Ion/Positive-Ion Coincidence Yields of Core-Excited Water

We report yields of mass-resolved negative ions and positive ions measured in coincidence after core excitation of water molecules. The analysis of negative-ion/positive-ion and negative-ion/positive-ion/positive-ion coincidence events provides new information on pathways leading to negative ion production, enhancing the present understanding of the dissociation processes of the water molecule. Dissociation following (resonant) Auger decay dominates negative ion production, but radiative decay is shown to contribute above the O 1s ionization threshold. A peak in the H(-)/O(+) yield above the O 1s threshold is attributed to decay from doubly excited states.

Preparing the MAX IV storage rings for timing-based experiments

Time-resolved experimental techniques are increasingly abundant at storage ring facilities. Recent developments in accelerator technology and beamline instrumentation allow for simultaneous operation of high-intensity and timing-based experiments. The MAX IV facility is a state-of-the-art synchrotron light source in Lund, Sweden, that will come into operation in 2016. As many storage ring facilities are pursuing upgrade programs employing strong-focusing multibend achromats and passive harmonic cavities (HCs) in high-current operation, it is of broad interest to study the accelerator and instrumentation developments required to enable timing-based experiments at such machines. In particular, the use of hybrid filling modes combined with pulse picking by resonant excitation or pseudo single bunch has shown promising results. These methods can be combined with novel beamline instrumentation, such as choppers and instrument gating. In this paper we discuss how these techniques can be implemented and employed at MAX IV.