DESCRIPTION

Small Angle X-ray Scattering (SAXS) experiments provide structural and dynamic information of large molecular assemblies like polymers, colloids, proteins and fibres. A wide range of fields (medicine, biology, chemistry, physics, archaeological, environmental and conservation sciences and materials) can be covered by this technique. SAXS is a very powerful technique that is used to study the supramolecular organization in biological systems, the structure and function of muscle filaments, corneal transparency, biological membranes, polymer processing, self assembly of mesoscopic metal particles, colloids, inorganic aggregates, liquid crystals and devices.

Recording simultaneously SAXS and WAXS (Wide Angle X-ray Scattering) results in a length scale which ranges from a few microns to a few angstroms.  

NCD Endstation   IM-BL11-NCDMonochromator

 

TECHNICAL SPECIFICATIONS

General specifications for the beamline NCD-SWEET have been measured and they match the theoretical calculations.

Wavelength range/Energy range   0.62 - 1.90 Å / 6.5 -20 keV
Flux at sample position
> 1.5·1012 ph/s at 12.4 KeV for a beam current of 150 mA
Bandpass (ΔE/E) 6.2 10-4 at 10.0 keV
Beam size at sample position
349 μm x 379 μm (h x v)

 

COMPONENTS

Source: In-vacuum undulator (IVU21)

The NCD-SWEET beamline is tunable over a wavelength range of 0.62Å - 1.90Å and delivers a high-photon flux onto the sample, the beam has an excellent beam collimation and photon density, and is also highly stable. For this purpose the photon source of this beamline is an undulator, U21, placed in a medium 4 m straight section.

Parameters:

Material Sm5Co17 Pure Permanent Magnet
Period 21.3 mm
Number of periods 92
K at minimum gap 1.6
Photon source size (FWHM) 309 x 18 µm2 (HxV)
Photon source divergence (FWHM) 112 x 28-22 µrad2 (HxV)

 

Optics

The chosen optical layout is aimed at delivering high-photon flux onto the sample. The position along the optical axis of key components are:

Centre of ID U21 0 m
Trigger unit separating Optics hutch and Front End 17 m
Double crystal monochromator; Si(111) 22 m
Collimating Be lenses 24.3 m
Sample position
32.5 m
Sample-Detector distance 2.1 m up to 7.2 m

 

SAMPLE ENVIRONMENT

Precision stage with vertical and horizontal motions for a maximum load capacity of 100 kg.

Travel rangeResolution
Horizontal Translation Stage 155 mm 0.0015 mm
Vertical Translation Stage 90 mm 0.00005 mm

 

  • Thermo-stated liquid cell (required volume on demand)
  • Non thermo-stated liquid cell rack for 24 samples (volume 0.030 ml)
  • Thermo-stated ladder for 6 capillaries (1 mm or 2 mm diameter)
  • Non thermo-stated ladder for 20 capillaries (1 mm diameter)
  • One film holder for 45 samples
  • 1 Linkam stage for 1.5 mm capillaries
  • 1 Linkam stage for 22 mm diameter films (the aperture for the beam is 2.5 mm centered on the film support).
  • 1 water bath

 

Linkam specifications
Linkam type Capillary Film
Min Temp (ºC) -196 -196
Max Temp (ºC) 350 600
Max Rate (ºC /min) 30 150

A sample platform that can accommodate a sample environment of up to 100 kg is available. The mounting area of the sample table is 750 mm x 750 mm. The breadboard of the sample platform has M6 screw holes with a 25 mm pitch.

If you would like to bring your own sample environment to NCD-SWEET for an experiment, we strongly recommend that you speak to a member of the beamline team well in advance of your experiment.

 

DETECTORS

The beamline currently uses a photon counting detector for Small-Angle X-ray Scattering (SAXS) and a CDD detector for Wide Angle X-Ray Scattering (WAXS) experiments. The SAXS detector is supplied by Dectris (Pilatus 1M) and the WAXS detector by Rayonix (LX255-HS). 

Visitors to the line must consider the actual sample-to-detector distance and choose it correctly in order to record the data of interest. In this context you need to consider the active area of the detector that will allow you to record the q-range of interest. Moreover, you must bear in mind that the accessible q-range for both SAXS and WAXS recordings is a function not only of the sample-to-detector distance, but also of the energy of the monochromatic photon beam.

 

Detectors specifications

 

Pilatus 1M detector
from Dectris

WAXS LX255-HS detector
from Rayonix
Mode SAXS WAXS
Active image area 168.7 x 179.4 mm2 (h x v) 85 x 255 mm2 (h x v)
Total number of pixels 981 x 1043 pixels (h x v) 1920 pixels x 5760 pixels (h x v)
Pixel size (not binned) 172 x 172 µm2 40 x 40 µm2
Frame rate 25 frames/sec 10 - 140 frames/sec (depending on binning mode)
Dynamic range 20 bits 16 bits