Submission deadlines:

New proposals and requests for beam time against existing proposals are accepted three times a year, in March, July, and October. A "rapid access" option is also available.

Review and allocation:

Proposals are peer reviewed and scored according to a set of review criteria. Time is allocated by a committee on the basis of scores and feasibility. The scores of unallocated proposals are "aged" or improved at each cycle as part of the allocation process. A user may appeal the outcome of a review.

Lifetime:

Proposals expire in two years or when the number of shifts recommended in the peer review have been used, whichever comes first. Rapid access proposals, other than macromolecular crystallography proposals, are good for one cycle.