APS USAXS/SAXS/WAXS facility

Ultra-Small-Angle X-ray Scattering Facility

Documentation

Experiment description for publications from USAXS/SAXS/WAXS instrument

Many users ask how to describe the instrument in a publication and what level of detail should be included. Some also request instrument drawings or include extensive technical descriptions that are usually unnecessary.

This instrument is a mature, well-established facility with more than 25 years of operation and over 750 publications. Detailed descriptions of the instrument design, performance, and configuration already exist in the literature.

As a general rule, your manuscript should focus on the scientific results, not on rewriting the instrument paper. In most cases, there is no need to include extensive technical details of the Bonse–Hart USAXS design or the associated SAXS/WAXS configurations. A brief description of the measurement setup, together with appropriate instrument references, is typically sufficient for readers who need additional technical information.

Here are some suggestions to follow:

  1. Ideally, the description should be two-three sentences long + citations.
  2. Experiment details - X-ray energy (21keV typically), beam size (typically 1x1mm USAXS and 0.8x0.2mm SAXS/WAXS), exposure time (typically 90 seconds USAXS, 2 seconds SAXS/WAXS), may be X-ray flux (typ. 5x1012ph/sec/mm2). Staff can verify the exact values in your data if you need it, let us know when data were collected and name of typical sample to check.
  3. Citation to instrument, see.
  4. Data processing and analysis citations (USAXS data reduction is USAXS paper and SAXS/WAXS needs Nika citation).
  5. How were the data reduced and processed: Did we put them on absolute scale? If you have thickness, then yes. Did you desmear the data presented in paper or not? This is important: Even if you model data in Irena as slit smeared, presenting slit smeared data in graphs in paper may cause confusion in review. It may be useful to desmear the data for graphs, unless they are just too noisy.
  6. Analysis method, if you use Irena add citation and method name/very simple basics. No details or formulas, use citations. But, for example, Unified fit has many citations and which is the right one depends on what application of that tool you want to present. 

That is all needed. No complex details, no instrument drawings unless really necessary (review papers). Utilize the following descriptions as starting point for Experimental/Instrument description in user publication, modify to meet the style you need and cite the Instrument papers. 

[USAXS+SAXS+WAXS]

Shorten & modify this example to reflect only needed details of experiment and correct values verified in notebooks or by staff:

USAXS, SAXS, and WAXS data were collected on the 12-ID-E beamline at the Advanced Photon Source at Argonne National Laboratory [instrument paper citation] using 21 keV X-rays. USAXS data collection time was 90 seconds, SAXS/WAXS 2 seconds each. Beam size was 1x1mm for USAXS and 0.8x0.2mm for SAXS/WAXS, flux density approximately 5x1012 photons/second/mm2. Samples were mounted using Scotch Magic Tape (3M) on instrument provided sample holder. USAXS data were reduced using instrument data reduction software provided by beamline and SAXS/WAXS data were reduced using Nika [citation]. Data were corrected for instrumental background as well as appropriate sample container scattering. Data were placed on absolute intensity scale [citation instrument paper]. Data were desmeared to remove instrumental slit smearing [Irena paper]. Data were analyzed using Irena package [citation] using name-your-model-here [citation for model, if available].   

NOTE: change instrument location appropriately based on when data were collected : 9-ID-C (until 8/2022), 20-ID-B (for 2023), and 12-ID-E (from 12/2024). 

The following much shorter texts are courtesy of Fan Zhang (NIST) who was kind enough to provide these very short but comprehensive descriptions. Note that these are written for 21keV, if your setup used different X-ray energy (ask beamline scientist), you need to modify that number. 

[USAXS + SAXS]

Absolutely-calibrated ultra-small angle X-ray scattering (USAXS) and small angle X-ray scattering (SAXS) experiments were performed using the USAXS instrument at Advanced Photon Source, Argonne National Laboratory. (Ilavsky et al., 2009, Ilavsky et al., 2013) The combined q range is between 1 × 10-4 Å-1 and 1.3 Å-1; here q = 4π/λ sin(θ), λ is the wavelength and θ is ½ of the scattering angle. The X-ray energy was 21 keV (λ = 0.5895 Å). X-ray photon flux was ≈ 5 x 1012 mm-2s-1.

[USAXS+SAXS+WAXS]

Absolutely-calibrated ultra-small angle X-ray scattering (USAXS), small angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS) experiments were performed using the USAXS instrument at Advanced Photon Source, Argonne National Laboratory. (Ilavsky et al., 2009, Ilavsky et al., 2013) The combined q range is between 1 × 10-4 Å-1 and 6 Å-1; here q = 4π/λ sin(θ), λ is the wavelength and θ is ½ of the scattering angle. The X-ray energy was 21 keV (λ = 0.5895 Å). X-ray photon flux was ≈ 5 x 1012 mm-2s-1. Combined USAXS/SAXS/WAXS measurements had a time resolution of 5 min.

Citations