The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Concepts, Definitions, and Help

Access to proposal information

Proposals can be edited (until the proposal is submitted) by the proposal spokesperson and by any experimenter included with an APS badge number. Proposal data is visible to users listed on a proposal, APS management, User Office staff, certain staff members of each beamline selected, the reviewers selected to evaluate the proposal, and the beam time allocation committee.

Notice to Users:

The U.S. Department of Energy Office of Science (SC), which is the primary sponsor of APS, requires that a limited set of information relating to your user project/experiment be transmitted to SC at the conclusion of the current fiscal year. A subset of this information, including your name, institutional affiliation(s), and project title(s), will be publicly disseminated as part of an SC user facility user projects/experiments database on the SC website,, after the conclusion of the fiscal year. For proprietary projects, SC requests that the user provide a project title that is suitable for public dissemination.

"Aging" of scores

The scores of unallocated proposals are "aged" or improved at each cycle as part of the allocation process. If a proposal was not allocated time in the previous cycle, its score is improved by 0.2. This is done for a maximum of two cycles, for a maximum improvement of 0.4. The score resets to the original value after an allocation of beam time.

Appealing a review score

A user may appeal the outcome of a review score. The user initiates the appeal by contacting the User Office. The Deputy Associate Laboratory Directory (ALD) for the APS will determine the action to be taken to resolve the appeal. The Deputy ALD may, at his discretion, request a re-review; all review comments will be provided to the user. An appeal does not guarantee a change in score or allocation. The proposal remains active after an appeal.

Beamline choice: "any appropriate beamline"

On each beam time request, the user may choose up to three beamlines that would be appropriate. Factors that could lead to time being allocated on the second or third choice include technical feasibility review by the first choice beamline, the score, or the number of number of shifts requested. If the option "any appropriate beamline" is checked, the request will be considered for any beamline where the work could be done.

Beamline choice: multiple beamlines

When time is needed on two different beamlines in one cycle (e.g., different techniques on same sample) create two beam time requests, each with a different first choice beamline. Be sure to explain in the proposal why work on both beamlines is needed.

Beam time requests (BTRs)

A new beam time request (BTR) must be submitted for each cycle in which the user wants time, and for each cycle, allocation is competitive. If a BTR does not get time in a given cycle and the proposal is still "active" with remaining shifts, do not submit a new proposal to request time again. Simply submit a new BTR in the next cycle on the same proposal. A proposal can have multiple BTRs.


Classified information is information that is required to be protected in the interests of national security under either the Atomic Energy Act of 1954 (as amended) or Executive Order 13526.


New proposals and beam time requests on existing proposals are accepted three times a year; see calendar.

Macromolecular crystallography (MX) access

There are two categories of general user access: "macromolecular crystallography (MX)" and "all other science." Proposals are "other science" by default; MX is requested through a question on the proposal form. The proposal form and the review and allocation process are then tailored for the MX community. Typically, time for macromolecular crystallography is handled through rapid-access beamtime requests.

Proposal form screen shots

Proposal life span

A standard general user proposal is valid for two years (six cycles) or until the approved shifts are used. A rapid access general user proposal (one received after the submission deadline) is valid for only that one cycle.

Proposal system tools

Save button: Save work in progress and be able to return to the proposal to continue editing at a later time.

Submit button: This sends your proposal to APS--submission of beam time requests is still allowed but no further editing of proposal content is possible.

Name lookup (on Experimenters tab): Use the "Find" buttons to search for collaborators either by last name or by badge number and to automatically fill in their contact information in your proposal.

File attachments (on Abstract tab): Charts and figures may be attached to support your abstract text and are useful to reviewers. Do NOT attach a .pdf of a prior proposal.

Search Criteria screen: You can click "Submit Query" without specifying any other criteria and the system will retrieve all the proposals that you are eligible to view.

Copy proposal button (at bottom of General tab): The Copy Proposal button copies most of the information from the current proposal into a new proposal and displays a new proposal that you may modify.

Generate report button (at bottom of each tab): The Generate Report button produces a PDF containing the information in the proposal. The report generation software has limited formatting capabilities, and the reviewers understand these limitations. Note that the report for a submitted proposal does not include any unsubmitted beam time requests.

Project status

Project status on a proposal allows for reliable, predictable beam time over several cycles (up to two years) on chosen beamline(s). The justification for project status (why the work cannot be achieved effectively under a GUP) is a critical component of the proposal. Additional levels of review apply and this status is granted very sparingly.

Proprietary access

The expectation is that users will publish their results in the open literature. Users who do not plan to publish must pay for proprietary beam time.

Rapid access mode

The "rapid access" designation is automatically applied to beam time requests (BTRs) received after the proposal submission deadline each cycle, regardless of whether the BTR is made on an existing proposal or on a new proposal. Beamline staff are notified when a BTR is submitted. If the beamline considers the proposed experiment acceptable and beam time is available, staff will contact the proposal spokesperson to schedule the experiment. A proposal submitted after the submission deadline is only valid for one cycle.

Review and allocation process

Proposals are peer reviewed and scored. Time is allocated on the basis of scores and feasibility.


Beam time at the APS is allocated in shifts of 8 hours.


The proposal spokesperson is the member of the team who receives all official communication about the proposal throughout its lifetime.


To comment on the contents, please contact or 630-252-9090.