Direkt zum Inhalt
  • Paul Scherrer Institut PSI
  • PSI Research, Labs & User Services

Digital User Office

  • Digital User Office
  • DE
  • EN
  • FR
Paul Scherrer Institut (PSI)
Suche
Paul Scherrer Institut (PSI)

Hauptnavigation

  • Research at PSIÖffnen dieses Hauptmenu Punktes
    • Research on Covid-19
    • Research Initiatives
    • Ethics and Research integrity
    • Scientific Highlights
    • Scientific Events
    • Scientific Career
    • PSI-FELLOW
    • PSI Data Policy
  • Research Divisions and LabsÖffnen dieses Hauptmenu Punktes
    • Overview
    • Research with Neutrons and Muons
    • Photon Science
    • Energy and Environment
    • Nuclear Energy and Safety
    • Biology and Chemistry
    • Scientific Computing, Theory and Data
    • Large Research Facilities
  • Facilities and InstrumentsÖffnen dieses Hauptmenu Punktes
    • Overview
    • Large Research Facilities
    • Facilities
    • PSI Facility Newsletter
  • PSI User ServicesÖffnen dieses Hauptmenu Punktes
    • User Office
    • Methods at the PSI User Facilities
    • Proposals for beam time
    • Proposal Deadlines
    • Data Analysis Service (PSD)
    • EU support programmes
  • New ProjectsÖffnen dieses Hauptmenu Punktes
    • SLS 2.0
    • IMPACT
  • DE
  • EN
  • FR

Digital User Office (mobile)

  • Digital User Office

Sie befinden sich hier:

  1. PSI Home
  2. Labs & User Services
  3. PSD
  4. SLS
  5. Super_XAS
  6. Optics

Sekundäre Navigation

SuperXAS

  • People
  • User Information
    • Operation Schedule
    • Useful Phone numbers
  • Ex Situ Sample Measurements
  • Beamline Layout Ausgeklappter Submenü Punkt
    • Source
    • Optics
  • Sample environments
    • Pump-Probe XAS
    • Johann XES spectrometer
    • von Hamos XES spectrometer
    • Capillary reactor setup
  • Publications
  • Scientific Highlights

Info message

Dieser Inhalt ist nicht auf Deutsch verfügbar.

Optics

General Layout

An overview of the beamline hutches is given below. The superbending magnet photon source and the front-end are to the left, inside the machine tunnel. A small sample-preparation and machine lab is situated at the rear of the beamline.

Top view of SuperXAS
Top view

Source

The following table shows the main properties of the X-ray source for SuperXAS.

Ring energy eE 2.4 GeV
Ring current eI 400 mA
Magnetic field B 2.9 T
Critical Energy Ec 11.1 keV
Electron beam size σX 46.3 µm
Electron beam size σY ~11 µm
Electron beam emittance εX 5.63 nm rad
Electron beam emittance εY 0.007 nm rad

Spectras of the superbending magnets are shown in the image below. The current superbending magnet with 2.9 T will be replaced during the SLS Upgrade to a superbending magnet with a variable field strength of 3.5 T or 5 T (changeable during machine shutdowns).

Bending magnet flux comparison SuperXAS

Optics

The optical components of the SuperXAS beamline, their functions and position from the source are listed here.

Beamline component Function Distance from the source [mm]
Graphite filter unit Beam attentuation 5970
White beam slits Definition of beam divergence 6364
Collimating mirror M1 Vertical collimation 7744
QEXAFS Monochromator MO1 Fast scanning, monochromatic beam 12980
Bremsstrahlungs stopper Block white- and pink-beam 13635
Monochromatic slits Beam definition (block scattering beam) 14145
Beam profile monitor Monitoring beam profile 14525
Focusing mirror M2 Bendable toroid, focusing the beam 15580
Beam profile monitor Monitoring beam profile 17276
Harmonic rejection mirror Rejection of high order harmonics ~22600
Main focus spot Main position for sample ~23600

X-ray mirrors

The high stability mirror system is designed to be very robust, reliable and to allow easy access for installation and maintenance. A very important design aspect of the mirrors systems is the complete mechanical separation between the optics and the vacuum chamber. This aims to avoid as much as possible vibrations propagation to the mirrors. A massive granite block directly supports the mirrors holders/benders that are mechanically isolated from the vacuum chamber by means edge-welded bellows.

The mirrors can be remotely adjusted in five independent degrees of freedom where the rotations (pitch, roll and yaw) are realized by means of software pseudo motors. The two (02) UHV compatible translation stages installed in the vacuum chamber with a UHV compatible stepper motor for each stage allow horizontal translation of the mirror. Thus, coating can be changed between Pt and Rh (plus Si coating for M1).

Vertical translations are performed by means of three (03) vertical jacks that also perform the pitch and roll rotations.

Property Collimating mirror (M1) Focusing mirror (M2)
Mirror substrate Monocrystalline silicon
Direction of Reflection Upwards Downwards
Shape Flat, cylindrically bent to tangential cylinder Sagittal cylinder, cylindrically bent to torus
Tangential bending radius 4.5 km to flat (>40 km) 3.0 km to flat (>40 km)
Sagittal bending radius Flat

20 mm (Pt coated)

30 mm (Rh coated)

Optical useful length 1000 mm
Optical useful width 3 x 20 mm (Si, Rh, Pt) 2x 34 mm (Rh, Pt)
Sagittal slope error < 10 µrad RMS < 20 µrad RMS
Tangential slope error < 1.5 µrad RMS < 2.5 µrad RMS
Micro roughness < 3 Å RMS
Coating

> 60 nm Rh, Pt

Cr underlayer

Cooling Max power load ~100 W, clamped side watercooling No cooling

The reflectivities of different mirror pitches are shown below for the mirror surfaces used at SuperXAS. Click on the image to enlarge.

Reflectivity-Si-mirror
Reflectivity Rh mirror coating
Reflectivity Pt mirror coating

Quick EXAFS monochromator (QEXAFS)

SuperXAS QEXAFS Monochromator

The QEXAFS monochromator consists of two channel cut crystals attached to a direct-drive torque motor. The system facilitates scan speeds for a specific energy range with up to 20 spectra per second (full EXAFS). Additionally, for low concentration samples, the monochromator can be operated in step-scanning mode by using the goniometer. The operational energy range can be selected by changing between the Si(111) and the Si(311) crystal and is in the range of 4.5 to 25 keV for the Si(111) and 9 keV to 35 keV for the Si(311). The crystals are cryo-cooled with LN2.

The system is a further development of the monochromator developed by Uni Wuppertal in Germany:

  • Müller O, Nachtegaal M, Just J, Lützenkirchen-Hecht D, Frahm R
    Quick-EXAFS setup at the SuperXAS beamline for in situ X-ray absorption spectroscopy with 10ms time resolution
    Journal of Synchrotron Radiation. 2016; 23: 260-266. https://doi.org/10.1107/S1600577515018007
    DORA PSI

Sidebar

Beamlines at SLS

Get an overview of beamlines at the SLS
top

Fussbereich

Paul Scherrer Institut

Forschungsstrasse 111
5232 Villigen PSI
Schweiz

Telefon: +41 56 310 21 11
Telefax: +41 56 310 21 99

Der Weg zu uns
Kontakt

Besucherzentrum psi forum
Schülerlabor iLab
Zentrum für Protonentherapie
PSI Bildungszentrum
PSI Guest House (in english)
PSI Gastronomie
psi forum-Shop

 

Service & Support

  • Telefonbuch
  • User Office
  • Accelerator Status
  • Publikationen des PSI
  • Lieferanten
  • E-Rechnung
  • Computing
  • Sicherheit

Karriere

  • Arbeiten am PSI
  • Stellenangebote
  • Aus- und Weiterbildung
  • Berufsbildung
  • PSI Bildungszentrum

Für die Medien

  • Das PSI in Kürze
  • Zahlen und Fakten
  • Mediacorner
  • Medienmitteilungen
  • Social Media

Folgen Sie uns: Twitter (deutsch) LinkedIn Youtube Facebook Instagram Issuu RSS

Footer legal

  • Impressum
  • Nutzungsbedingungen
  • Editoren-Login