WLE - Wiggler Low Energy Beamline (7-22 keV)


Welcome!

         The WLE beamline has three endstations supporting the following techniques

  • High-Resolution Powder X-ray Diffraction                         15.1 keV with Si(111)
  • SAXS/WAXS                                                           9.8 keV with Si(111), or 18.8 keV with Si(311)
  • IBM Endstation                                                       7.1 keV with Si(111), or 13.7 keV with Si(311)

Scroll down this page to find out more! We offer a mail-in access option for all techniques

Please contact Adam Leontowich for questions related to the WLE beamline

 

Beamline technical details and performance

 

Click here for a pdf copy of the WLE beamline paper

Leontowich, A. F. G., Gomez, A., Moreno, B. D., Muir, D., Spasyuk, D., King, G., Reid, J. W., Kim, C. Y., and Kycia, S. ‘The lower energy diffraction and scattering side bounce beamline for materials science at the Canadian Light Source.’ J. Synchrotron Rad.28 (2021) 961-969

  

Measured performance

  • Energy range:                                       7 – 22 keV
  • Flux, @ 220 mA, minimum gap:         1012 photons/s with Si(111), or 1011 with Si(311)
  • Beam size, FWHM:                              Better than 150 μm V × 500 μm H
  • Energy resolution, ΔE/E:                    2.5 – 6.4 × 10-4
  • Divergence:                                           200 – 300 μrad V × 730 μrad H

  

High-Resolution Powder X-ray Diffraction (PXRD)

In March 2024, a major CFI funded upgrade to our PXRD instrument was completed! We added a robot arm, an automated sample spinning alignment system, and went from 1 to 8 Mythen detectors. We are now able to run a fully automated batch mode of up to 96 samples, at a rate of less than 5 minutes per sample, with even better quality data!

 

 

This endstation operates at a fixed photon energy of 15132.8 eV (λ = 0.81931 Å), using the Si(111) crystal in the beamline monochromator. There are eight Dectris Mythen2 X series 1K "linear strip" detectors. Each has 1280 pixels, which are 8 mm wide by 50 μm tall, for a total active area of 8 mm × 64 mm per detector. These are direct detection with 1 mm thick silicon as the sensor. The response is linear up to 700,000 counts/s, with practically no dark noise, and an acquisition rate up to 1000 Hz.

The detectors are 760 mm from the sample and spaced 10º apart. For typical data collection, 2θ is scanned 10º, (from 3° - 13°, with 2θ = 0° defined as the center of the lowest angle detector) acquiring every 0.25º for 2 seconds. This effectively collects a 2θ range of 1.6° - 84°, which is a q range of 0.22 Å-1 - 10.26 Å-1, or a d spacing range of 28.5 Å - 0.61 Å. Samples are spun at a rate of 2 Hz during measurement. A fast shutter is synchronized to the detector acquistion to minimze the radiaiton exposure. The full measurement cycle (transfer on - align - measure - tranfer off) is 4 minutes 30 seconds per sample.

This endstation can be paired with the Oxford Cryostream 800 Plus for temperature control (80 - 500 K). Please give advanced notice as the Cryostream is a shared resource within the BXDS sector.

 

PXRD sample preparation and mounting  ***PLEASE READ***

Users are strongly encourged to prep all samples as detailed below before your scheduled time. The data acquistion is very rapid, and the beamline is oversubscribed; If you choose to prep samples during your assigned time, you will receive less time than what you request for your next visit.

Prepare a nice powder: The first step of good sample prep is always to grind your materials very well, down to a fine powder, in a mortar and pestle. Large grains will reduce the quality of the data. If the sample is a mixture, and the mixture is not homogeneous within the beam area (150 um V x 500 um H FWHM), the phase fractions measured will not be reproducible.

Purchase some capillaries: Users will pack their powdered samples into capillary tubes: Standard capillaries for this endstation are polyimide/kapton, 0.5 mm inner diameter. These capillaries are sourced from VWR, part MFLX95820-04. Samples which are very air-sensitve, or those which are simply not compatible with kapton can be loaded in quartz capillaries and flame sealed. These can be purchased as a custom order from Friedrich and Dimmock: 0.5 mm ID, 0.7 mm OD, 75 mm total length.

Consider sample absorption: For each sample, you will need to calculate the sample absorption or muR at our wavelength of 0.81931 Å. We use the free program MAC 3.0 for the calculation. It can be downloaded here. This APS website provides useful guidelines for acceptable absorption. The choice of capillary diameter is dependent on the X-ray absorption of the sample. Samples with a large fraction of high Z elements may produce the best data within 0.3 mm capillaries. If calculated muR is still >3 in a 0.3 mm capillary, the sample can be diluted. Crushed up fused silica glassware works well for diluting samples. Dilute highly absorbing samples so that the muR is less than 3… muR around 2 seems to be best.

Proper size and sealing is IMPORTANT:  The capillary should ideally be 20 mm long (not more than 25 mm, and not less than 10 mm). Pack the powder in to create a plug of material at least 4 mm long (preferably as full as possible). Kapton capillaries must be sealed on both ends with wax or superglue, even if the compound is not air sensitive. Take care not to form a bead of glue at the end which is wider than the capillary, or it may not be possible to fit it in the magnetic stub holder. If the sample is air-sensitive, ship it within one or two air-tight containers purged with dry inert gas (for example, a capillary in a small glass vial inside a small plastic bag). These packages can be opened at the beamline immediately before the data collection.

 

 

The sealed capillary is then mounted on a reusable magnetic stub with a small amount of wax. The magnetic stubs are from Mitigen, Goniometer Base Type B3S-R, GB-B3S-R-40. We will provide the stubs for users. The capillaries are measured oriented horizontally at a slight downward angle of 2º, and spinning at a rate of 2 rotations per second.

We generally do not mail stubs or capillaries to users. You send or bring the pre-prepared capillaries, which are mounted to stubs on-site. Some users buy their own set of stubs so all sample prep steps are complete in advance.

For best results, we encourage users to,

  1. Prepare all samples in capillaries ahead of the scheduled beamtime, as detailed above.
  2. Create a priority list. Ensure that your most important measurements get done first in case there are unexpected problems.
  3. Use a very simple naming convention for your samples (A1, A2, A3, B1, B2, C1, etc.). This makes it much easier for staff who receive hundreds of samples a week.
  4. For a PXRD proposal, estimate 2 hours for initial instrument setup and calibration, and 10 minutes per sample at room temperature. If temperature control is required, mention you require the Oxford Cryostream for temperature control, and any proposed ramps.

PXRD data format and how to view your data

When you receive your data we will typically include three types of files:

  • Files with the extension .xye are the important PXRD data. The format is essentially that of TOPAS data with no header. The first column is 2θ, the second column is intensity in counts/s, and the third column is error. PyMCA is a free program also useful for quickly viewing the patterns. We use the free program GSAS-II for most PXRD data workup. These files open in GSAS-II (import, powder data, guess format from file). When it asks for an instrument parameter file, load in the BXDS_Huber.instrprm file available below for dowload. Now the data file should open. By refining the data for the calibration standard LaB6, using the .cif file for LaB6 available for dowload below, you can create, save, and apply your own instrument parameter file to the data.
  • The files with no extension are the individual frames from the scan, and can be viewed with PyMCA. These frames get merged together to form the .xye files. Typically users will not need these, but they can sometimes be useful.
  • Lastly, there are files that end in _spec. These contain additional information collected during the scans, such as ion chamber readings and the ring current for each point in the scan.

 Click here to download a collection of helpful PXRD files:

  • A GSAS-II instrument parameter file specific for the Huber endstation (last updated April 12, 2024)
  • Example of a .xye file for LaB(NIST 660b)
  • Example of the MAC program with details entered for LaB6, courtesy of Joel Reid
  • .cif file for LaB6
  • Information from NIST on the LaB6 calibration sample (NIST 660b) 
  • A step-by-step tutorial for how to refine LaB6 in GSAS-II, courtesy of Joel Reid

  

SAXS/WAXS

Our fastest growing user community! We are working toward a new table and detector bracket design, which will enable a faster switch between SAXS and WAXS modes. Expected completion is Fall 2024.

This endstation has a choice of two fixed photon energies: 9846.6 eV (1.25916 Å) with Si(111), or 18836.9 eV (0.658204 Å) with Si(311). 9.8 keV is generally better for measuring in grazing incidence geomerty, SAXS of liquids, reaching our lowest possible q value for SAXS, and organic materials. 18.8 keV is generally better for transmission through thick and dense materials, reaching the highest possible q value for WAXS, and inorganics such as battery or perovskite materials. 

The detector is a Rayonix MX300 phosphor coupled CCD. The area is 300 mm × 300 mm, with minimum pixel size of 73.242 μm × 73.242 μm (4096 × 4096). The acquistion rate can be as fast as 2 Hz, in 4×4 binning mode. The maximum counts per pixel is 216 = 65536. The beamstops which protect this detector are by default 4.0 mm diameter with an embedded photodiode.

A variety of q ranges are possible, and these configurations are listed below in units of inverse angstroms.
Click here to see the same table of q ranges with units of inverse nanometers.
Click here to see the same table in d spacing range with units of nanometers

We use a four stage stack for sample manipulation. Measurements can be performed in transmission or grazing incidence geometry (minimum θ step = 0.01º). The endstation can be paired with a several special environments available at the beamline:

We are also open to putting your device in the endstation! We have accommodated user-designed tensile stages, heating stages, solar simulators, humidity control, etc. Contact staff well in advance when requesting a special sample environment.

We can measure powders, thin films. liquids, pharmaceuticles, nanoparticles in solution or on surfaces, micelles... the list goes on! For liquids, we generally need minimum 40 uL for the measurment. SAXS of liquids requires concentrations of 10 mmol, or about 1 to 10 mg/mL, if you are interested in the form factor. Liquid samples are measured in quartz capillaries (buy the 1.5 mm, no funnel, open on both ends, part Quartz 15-SQZ - 1.5mm), and users are expected to bring their own capillaries. We supply silver behenate and LaB6 (NIST 660b) for the detector calibration, and glassy carbon (NIST 3600) as an absolute intensity standard.

For best results, we encourage users to,

  1. Let us know in advance the q (Å-1) or d spacing (Å) range you are interested in. This will minimize setup time and we can optimize the setup for your specific problem. Our currently available q ranges are tabulated above.
  2. Create a priority list. Ensure that your most important measurements get done first in case there are unexpected problems.
  3. Use a very simple naming convention for your samples (A1, A2, A3, B1, B2, C1, etc.). This makes it much easier for staff who receive hundreds of samples a week.
  4. For a WAXS or SAXS proposal, estimate 2 hours of initial setup time for WAXS, or 4 hours for SAXS. When switching from SAXS to WAXS, or changing the photon energy, estimate 2 hours setup time. When switching from WAXS to SAXS, or a SAXS configuration change of the flight tube, estimate 4 hours setup time. Because of the great flexibility of this endstation, and the wide variety of samples, sample throughput varies greatly, between about 5 and 30 minutes a sample at ambient conditions. Consult with beamline staff. Changing energy, SAXS tube length, and switching from SAXS to WAXS is done by staff. These can all be accomodated during your run, however configuration changes must start and conclude within the hours of 9 am - 4 pm, Monday to Friday. Please tell us if you plan any configuration changes ahead of beamtime. After hours and weekends may be possible with advanced noticeStaff are not normally on site between 4:30 pm and 8 am, or weekends. And, we have kids :) Asking for a configuration change at 3:30pm that takes 2 hours will likely be declined. 

SAXS/WAXS data format and how to view your data

Data from the Rayonix detector are images in the .tif file format. The files are 33 MB each in smallest pixel mode, so take care to manage the amount of unnecessary images collected. For example, avoid collecting images during initial alignment scans or delete them. The free program ImageJ is installed at the beamline for a quick visual check of the image quality.

We use the free program GSAS-II for some SAXS/WAXS data workup. The .tif files open in GSAS-II (import, image, from TIF image file). Now the data file should open. By refining the data for the calibration standard such as silver behenate or LaB6, you can calibrate the detector, and then apply the calibration to your data to perform azimuthal integrations in units of q. A tutorial that can be downloaded here, within the folder SAXS tutorial.zip. GSAS-II also has excellent turtorials which fully describe these steps (click help, tutorials, browse tutorial on web, "calibration of an area detector", and "integration of area detector data").

  • The free Matlab program GIXSGUI is popular for more advanced GIWAXS data workup including creating missing-wedge figures.
  • The free program BornAgain is excellent for modeling and analysing GISAXS data.
  • The free program BioXTAS Raw is excellent for SAXS analysis (Guinier, Kratky, PDDF).

 

IBM Endstation: In-Situ Rapid Thermal Annealing

  

This endstation can operate at two fixed photon energies: 7159.2 eV (1.73184 Å) with Si(111), or 13691.0 eV (0.90560 Å) with Si(311). Typical operation is at 7.1 keV, except some circumstances where greater penetration through high Z elements is required.

This endstation is highly specialized for rapid thermal annealing experiments on metallic thin films and multilayer structures under controlled atmospheres. It can perform simultaneous X-ray diffraction, four point probe resistivity measurements, and surface roughness measurements on thin films during rapid annealing, up to 1100°C. It is generally for industry use but has been made available for specific user experiments. Please discuss your IBM endstation proposal with beamline staff before submitting.