Advanced Photon Source

A U.S. Department of Energy, Office of Science,
Office of Basic Energy Sciences national synchrotron x-ray research facility

APS 32ID-B USAXS Ultra-Small-Angle X-ray Scattering Facility
instrument scientist: Jan Ilavsky, 630-252-0866, ilavsky@anl.gov
data reduction Indra Irena livedata photos

Examples of USAXS data

Silica spheres in solution

Slit smeared configuration, “rocking-curve data”. These data are photodiode intensity (divided by monitor ion chamber intensity) as a function of Q vector. The data are corrected for photodiode/amplifier dark current, but no other correction is done.
The data for silica spheres in solution after all corrections – after subtracting blank from the sample measurement, calibration and desmearing.
The same data as above measured on pin hole collimated instrument (SBUSAXS). First the rocking-curve data.
The data from above, blank subtracted from the sample measurement, calibrated, this time no desmearing routine was needed.

Glassy Carbon

Glassy carbon SAXS intensity standard.

Absolute intensity conversion

For details of the conversion of raw intensity to absolute units of differential scattering cross-section per unit volume per solid angle, please consult:

• Our absolute intensity page
• Pete Jemian's 1990 PhD thesis, http://www.jemian.org/pjthesis.pdf, page 51, equation 83.
• G.G. Long, P.R. Jemian, et al., J Appl Cryst 24 (1992) 30-37.
  High Resolution Small-Angle X-ray Scattering Camera for Anomalous Scattering