Advanced Photon Source at Argonne National Laboratory   APS USAXS instrument
USAXS instrument at the Advanced Photon Source,
X-ray science division, beamline 9ID-C

Advanced Photon Source

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

Argonne Home > Advanced Photon Source > USAXS >

Staff web pages:
      Jan Ilavsky, inst. scientist

      Glassy Carbon int. stnd.
      Example USAXS data
      Getting beam time
      Instrument Geometries
      USAXS imaging
      Sample Holders
      Select publications
      User publications
      Shipping Instructions
Live USAXS data
Software by Jan Ilavsky:
      Indra (reduction)
      Irena (analysis)
      Nika (2D data reduction)
      Cromer-Liberman AtFF
      Clementine (kinetic rate analysis)
      other macros
Useful WWW links

Ultra-Small-Angle X-ray Scattering Facility

e-mail:, instrument scientist: Jan Ilavsky, 630-252-0866, and Ivan Kuzmenko, 630-252-0327,

Data collection and evaluation

The USAXS instrument is run using software package called Spec. The data collected by Spec are written into the structured ASCII file. The spec provides programmable command line environment and automatic data collection.

Standard SAS data collection

Standard small-angle scattering (SAS) data collection is the most-used mode in which this instrument is used. In this case one collects triplets of Q, Intensity, error for range of Qs. The absolute calibration is part of the data collection process. The procedure in short includes:

1.      Samples are mounted into sample holder.

2.      Using radiography the samples are located and their positions are recorded. For large samples this step can be skipped and positions can be measured by ruler.

3.      Command file is written.

4.      Command file is executed. Data are collected for each sample. Depending on the Q range studied, measurement time and number of steps in Q taken for each sample, the collection of data from one sample takes anywhere from 15 to 120 minutes. Most used conditions result in about 20 minutes per sample. Since there is need to collect blank (instrumental curve) for about each 3 6 samples, it is possible to process about 2.5 samples per hour - assuming the APS storage ring does not have beam dump and everything else works fine.

5.      With improvements in stability of the instrument and added automatic procedures it is possible now to program large number of samples for overnight runs.


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This page last modified: 2006-09-28 10:54 AM