General users are granted beam time through a peer-review proposal process. They may use beamlines and endstations provided by the ALS or the Participating Research Team (PRT) that operates the beamline.
Before Submitting a Proposal
- Review the ALS Beamline Directory to learn about the research capabilities of individual beamlines. Contact the primary contact listed for the beamline for additional information.
- You can improve your proposal by reading the proposal writing guidelines and scoring criteria.
Log in to ALSHub to submit a General User Proposal (GUP).
January–June operating cycle: 1st Wednesday in September
July–December operating cycle: 1st Wednesday in March
Proposals are accepted until 11:59 pm, Pacific Time Zone on the Wednesdays above.
Maintaining an Active Proposal
GUPs typically remain active for two years (four cycles) or until the number of shifts recommended by the PSP for the life of the proposal has been used. Users may decide whether to submit a new proposal or make a beam time request on an active proposal based on the cutoff score for that beamline.
Please note that proposal scores may be adjusted in subsequent cycles, as follows:
- Proposals that are allocated beam time in the first cycle will retain the same score.
- Proposals that do not obtain beam time in the first cycle will have their score ‘improved’ (score decreased by 0.2). This should increase the probability of obtaining beam time for proposals close to the cutoff. The aim is to help these users to write an improved proposal.
- If a proposal with an improved score is allocated beam time, the score will revert to the original score for future cycles.
Proposal Review and Scoring Process
All submitted proposals are reviewed by:
- ALS staff for technical feasibility and safety;
- up to four external reviewers; and
- the PSP, which determines the final scores of proposals and makes recommendations concerning requested beam time.
GUPs are scored on a scale of one to five, where one is the highest score. Beam time is then assigned based on each proposal’s ranking in relation to all other proposals for a given beamline. Proposals for oversubscribed beamlines may be moved to alternative beamlines with appropriate capability. See proposal score statistics for the current cycle’s scoring details.
Allocating Beam Time
Once all proposals have been reviewed and assigned a score, beam time for general users is allocated by the ALS User Office in consultation with the beamline scientist. This process is overseen by the ALS Deputy Division Director for Science. The available beam time is allocated according to the rank order of score, beginning with the best score and continuing until the beam time allotment for general users has been met.
Responses to the proposals are sent via email approximately three months after the submission deadline. Each proposal is given a numeric rating that is communicated to the PI and the experimental lead, along with comments from the external reviewers and PSP.
Beamtime schedules are finalized by the beamline scientist in consultation with users. See the ALS Beamline Directory for beamline scientist contact information.