Beamline Information

Spatial resolution

2 x 2 µm

Energy range (keV)

2.05 - 20.5

Energy resolution (Δ E/E)

Si 111: 1.4 x 10^-4

Energy stability (eV)

+/- 0.05 per day

Full beam size Flux @ 10 keV at sample (ph/s)

2 x 10¹²

Beam size at sample (µm) at full flux

7 (H) x 2 (V)

Minimum beam size at sample (µm)

2 (H) x 2 (V)

Beam divergence at sample (mrad) (FWHM)

3 (H) x 2 (V)

Beam position stability at sample

<1 µm per day

• I18 is based on three mirrors and a double crystal monochromator.

• Rh-coated Silicon toroidal mirror sits 25 m from the source focusing the beam horizontally and collimating vertically 37.5 m from the source.

• A fixed-exit monochromator with Si(111) and Si(311) crystals sits 27.7 m from the source covering the energy range 2.05 – 20.5 keV.

• There is a pair of plane mirrors for harmonic rejection at low energies ( <4 keV) using either Rh or Ni stripe.

• Mechanical Kirkpatrick-Baez (KB) focusing mirrors with Si and Rh stripes. These are non-chromatic, ideal for energy scanning applications like EXAFS (extended X-ray absorption fine structure) operating over the full beamline energy range.

• Typical focus 2 - 5 (V) x 2 - 5 (H) micron spot size. Can be defocused up 100 microns. Alternatively, KB Mirrors can be removed from the beam path for bulk XAS with a spot size ~ 400 microns.

Insertion device

U27 in-vacuum undulator

Nominal magnet length (m)

2

Nominal magnet gap (mm)

7

Magnet period (mm)

27

Detector

Specifications

Excalibur XRD Detector

16 MEDIPIX3 chips read-out at 100 frames per second in continuous mode or 1000 frames per second in burst mode - if burst mode is required, you must speak with beamline staff prior to proposal submission. A total detection area of the 3-module EXCALIBUR detector is 115 mm × 100 mm with a small 6.8 mm wide inactive region between modules and pixel size of 55 microns.

Vortex Si Drift Detector

Two x 4 element 1mm thick sensor Vortex Si Drifts detector with cube pre-amps, Xspress 3 electronics

Avalanche Photo Diode

FMB Oxford APD detector is an ultra-fast detector, using an avalanche photo diode up to 20keV.
Ultrafast detector ideal for experiments with a large dynamic range, time resolved measurements and fast photon counting.

Ionisation Chambers

Transmission measurements (He, N₂, Ar, Kr gases)

Excalibur XRD detector

Vortex Si Drift Detector