For Prospective Users: Learn About X-ray Research

Welcome to your orientation to the framework for user research at the APS.

Why is the APS special?

APS The Advanced Photon Source is a synchrotron light source that produces high-energy, high-brilliance x-ray beams. The source is optimized to put large quantities of high-energy photons into a very small area in a very short time.

The x-ray beam is customized at each beamline to meet particular needs. With more than 40 beamlines already operational, and more under development, the APS offers an exceptionally broad range of experimental conditions at a single facility. It is also conveniently located at Argonne National Laboratory, 30 miles southwest of Chicago, Illinois, with two nearby airports offering many travel options.

Scientists from around the world come to the APS to conduct forefront basic and applied research in the fields of materials science; biological science; physics; chemistry; environmental, geophysical, and planetary science; and innovative x-ray instrumentation. To get an idea of the range of work currently being done at the APS, please see the Science section.

What experimental conditions are available?

Beamline diagram Each beamline at the APS offers a unique combination of capabilities, but some of the main considerations are energy range and tunability, special sample environments, time structures, and beam size.
  • The energies used range from relatively "soft" x-rays (3-5 keV) to "hard" x-rays at 100 keV and sometimes higher. At many beamlines, the energy can be tuned with relative ease.
  • Samples can be examined under extreme conditions of temperature and pressure, and several facilities are available for samples requiring special handling (e.g., biohazards, radioactive samples).
  • Many experiments involve timing, through correlation with a pulsed laser or with the time structure of the x-ray pulses, for example. In the typical operating mode, the x-rays come in evenly spaced bunches or pulses, with 0.31 mA per pulse and 11.37 nanoseconds between pulses.
  • Some beamlines employ additional optics to narrow the already tight beam into even smaller spots, offering spatial resolution into the 50-nm range.

How is beam time made available?

APS user at work The machine operates for 3 three-month runs (or cycles) each year, with a one-month shutdown between runs. The runs typically span February to April, June to August, and October to December.

In general, the APS makes beam time available to the international scientific community in two ways: General User access and Partner User access. Specific requirements govern both modes of access.

  • General Users are those who require less than 10% of the beam time on a beamline in a given cycle. Proposals from General Users are considered through a web-based process three times a year.
  • Partner Users are those whose work involves a greater scope and greater commitment by both the user and the APS.

One kind of Partner User is a Collaborative Access Team (CAT). A user whose home institution is a member of a CAT may be eligible to request beam time through the CAT. Options for time-sensitive access are available.

What are the requirements?

For research that will be published in the open literature, there is no charge for beam time. Users are expected to notify the APS of publications resulting from work conducted here. For proprietary work, an hourly fee is charged to recover facility costs.

Because Argonne National Laboratory is a controlled-access site operated by the U.S. Department of Energy (DOE), APS users must follow DOE requirements regarding permission to enter the site (especially for users who are not U.S. citizens), training, safety practices for experiments, shipping of samples and equipment, etc. However, APS and beamline staff work very closely with users to help them fulfill these requirements.

How do I get started?

The following are the key first steps.

  1. Decide where you want to work. Read about APS science and communicate with beamline staff to decide which beamlines are suitable for your purposes. Start by visiting Find a Beamline page, where you will find a techniques directory and a beamline directory. Consult the techniques directory to see which beamlines support the techniques you need. The beamline directory will point you to detailed specifications and contact information.
  2. Arrange for access to the Argonne and APS sites. The first step is to register as a user, which sets other administrative processes in motion. more>>
  3. Request beam time in a specific cycle. If you will be working as a General User, you must submit a proposal. more>>

If you have any questions about working at the APS, please contact the User Office at 630-252-9090 or