APS 9ID USAXS/SAXS/WAXS

Ultra-Small-Angle X-ray Scattering Facility

Documentation

Experiment description for publications from USAXS/SAXS/WAXS instrument

Many users ask how to write instrument description in paper and what to include. Some ask for instrument drawings and include needless details. This is known, more than 20 years young, instrument with 550+ publications in the past 20 years. Do NOT try to write our instrument paper, write your scientific paper. As general rule, it is not advisable to go in complicated details of Bonse-Hart instruments or our SAXS and WAXS configuration. There is no need, this instrument has sufficient number of instrument publications which describe, in detail, instrument setup and everything else which may be of interest to readers.

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 0.8x0.8 USAXS and 0.8x0.2mm SAXS/WAXS), exposure time (typically 90 seconds USAXS, 20 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. There are two, one older and one newer.  At least the newer one. 
  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 it. No unneeded details, no instrument drawings unless really necessary (review papers). Include following descriptions, modify to meet the style you need and cite the Instrument papers. 

The following short texts are suitable as starting point for Experimental/Instrument description in user publication.

[USAXS+SAXS+WAXS]

Bit too long example. It MUST be shorten & modified to reflect only needed details of published experiment and correct values verified in notebooks or by staff:

USAXS, SAXS, and WAXS data were collected on the 9-ID-C 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 20 seconds each. Beam size was 0.8x0.8mm 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].   

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