Technical details


A multipole superconducting wiggler (SCW) is the source of the Xpress beamline. This source is shared with the XRD2 beamline.

Superconducting wiggler
Mask after SCW
11-2 beamline overview
Superconducting wiggler


The main parameters of the SCW are given in the table below: 
 Period length   64 mm
 Peak field   3.5 T 
 Total no. of poles   49
 Pole sequence  1/4, -3/4, 1, -1...
....1, -3/4, 1/4
 Internal aperture  81 mm (H) x
 10.7 mm (V)
 Total powder       18.3 kW

A factor of 3 (14) higher flux will be obtained from SCW compared to the permanent magnet wiggler of the already present diffraction beamline (XRD1) at 12.5 keV (25 keV). The SCW also result in a smaller source size due to the shorter wiggler length (1.4 m instead of 4.5 m).  The detailed design and manufacture of the SCW has been done at the Budker Institute of Nuclear Physics, Novosibirsk. An upgrade of the original cold-bore design (with internal 20 K copper liner to efficiently absorb the thermal load from scattered photons and r.f. heating) has been done in order to reduce the liquid He consumption. The SCW has been reinstalled in July 2013 and is currently in routine operation.

Optical elements

A silicon crystal (flat monochromator) hosted in the splitter chamber in the FrontEnd section of the XRD2 and Xpress - intercepts the beam from the source and direct it to the focussing mirror at fixed energy of 25 keV. The monochromator is composed of a single slab of Si with surface cut along (111) direction and cooled to LN2 temperature by a cryocooler.

Splitter scheme
Xpress monochromator crystal
11.2 beamsplitter
Automatic LN<sub>2</sub> cooler
Splitter scheme

The Focussing mirror is a 1.4 m long torus, Pt coated to achieve 80% reflectivity at 25 keV and 2.9 mrad grazing angle.

Mirror vessel drawings
Focus mirror (drawing)
Focus mirror
Mirror vessel drawings


Experimental station

An image plate MAR345 is used to collect the diffraction pattern. MAR345 is placed in a stage with a precise linear movement control permetting an easy control over the distance between the sample and the image plate. Two vertical positions are curently available for the image-plate (beam center to be at the center of the active area or in the bottom corner).

At present we can run ambient temperature high pressure powder diffraction experiments using diamond anvil cells (DAC) for a pressure range of 0-50 GPa. Currently we welcome users who are ready to bring their own DAC and manage the sample loading in the DAC.

High Pressure Support Facilities

A Zeiss (Discovery V20) microscope is available for the DAC loading. For the gasket hole drilling a Boehler microDriller (Almax easyLab) is available.  A BETSA PRL set up is fixed to the experimental table for monitoring the pressure through ruby fluorescence.

BETSA ruby fluorescence
MicroDriller</span><span style=\"font-family: monospace; font-size: medium; line-height: 20.8px;\">
Zeiss V20 microscope
BETSA ruby fluorescence

Last Updated on Thursday, 21 July 2016 14:54