Beamline B07 is designed to provide dipole synchrotron radiation of soft X-rays between 50 and 2800 eV (< 1012 photons s-1 over the entire energy range) for studying atomic structures and electronic/chemical properties of surfaces and interfaces by Photoelectron Spectroscopy (XPS) and Near-Edge X-ray Absorption Spectroscopy (NEXAFS).
A schematic view of the beam line layout is shown below. The beam line is designed to have separate sources and optical components that will allow independent and parallel operation of two soft X-ray branchlines; B07-1 (Ambient Pressure) and B07-2 (High Throughput).
B07-1: Ambient Pressure branchline
The ambient pressure end station is a modular system that should allow maximum flexibility with respect to sample environments. The concept includes an interface flange which combines the entrance nozzle of the ambient-pressure electron energy analyser and the beamline interface, both of which are differentially pumped, and exchangeable reaction/experiment cells, as illustrated in the Figure below. The maximum pressures that the beamline interface/analyser assembly is expected to maintain are 100 mbar for H2 and 50 mbar for H2O.
It is envisioned that different reaction cells can be fitted depending on user needs. For instance a simple reaction vessel could be used when ultra high vacuum is not required and dosing of gas is a priority, whereas a full UHV chamber could be used for experiments requiring ultra clean environments. Please contact the beamline staff to discuss possible options.
|Energy range||250 - 2800 eV|
|Energy resolution (ΔE/E)||5000 (250 eV - 2500 eV)|
|Minimum beam size at sample (FWHM)||48 μm (H) × 21 μm (V)|
|Photon flux||> 1 × 1010 ph/s|
|Beam position stability at sample||< 5 μm/h; < 10 μm/day|
B07-2: High Throughput branchline
The high throughput end station will consist of an ultra-high vacuum (UHV) end station, b1, and an extra focus for user-built end stations, b2. The optics of branch B will be optimised for X-rays in the range 50 – 1500 eV. The spot size at the sample is expected to be < 100 μm x 100 μm.
This end station will focus on samples that do not require such high ambient pressures, but which are still often incompatible with ultra-high vacuum requirements due to outgassing. Users studying this kind of samples often wish to screen relatively large numbers of samples, therefore the b1 end station will have moderate vacuum restrictions and automated sample manipulation for high throughput to enable automatic screening of samples.
An additional focus (b2) will be provided in order to facilitate the development of new or less common detection techniques for soft x-ray absorption spectroscopy (such as x-ray fluorescence and optical luminescence) in combination with scanning probe techniques. This allows the pressure limits to be pushed even higher than what is possible with electron-based methods, even allowing the study of molecules in solution. In addition, luminescence detection enables spatial resolution at the level of optical microscopy (~10-6 m), whereas scanning probe detection would push the limits down to the nanometer range. To this end the beamline will offer the possibility to attach small user-built endstations to use new detection devices.
|Energy range||50 - 2000 eV|
|Energy resolution (ΔE/E)|| |
5000 @ 500 eV
|Minimum beam size (H × V) at sample (FWHM)||≤ 100 μm × ≤ 100 μm||≤ 200 μm × ≤ 200 μm|
|Photon flux at sample||≥ 1 × 10 ph/s|
B07 is equipped with a sample preparation (SP) room for standard sample preparation and mounting. Raw water and compressed air are supplied.
Gas Mixing Rig
The AP-ES will have a gas mixing rig capable of creating mixtures of several reactive gases.
See below for beamline floor plan.