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Program Advisory Committee (PAC)

PAC 21 Call for Proposals

October 2, 2001

Dear Jefferson Lab User,

The Jefferson Laboratory Program Advisory Committee (PAC 21) will consider new proposals, updates, and letters-of-intent during the week that begins January 14, 2002. Proposals for PAC 21 are due at Jefferson Lab by the close of business on Monday, December 3. PAC 21 will also review the schedule for experiments in the three halls. As is the established tradition, the JLab Technical Advisory Committee (TAC) will make comments on the technical viability of the proposals and provide these comments to the spokespersons and the PAC prior to the meeting. As always, proposals will be judged on the quality of the physics, technical feasibility, and the ability of the group to carry out the proposed measurements.

The backlog of approved experiments at Jefferson Lab remains large (over 4 years in Halls A and C, and 3 1/2 years in Hall B) for our present schedule and operating efficiency, although it has been reduced by the jeopardy process in all three halls. To keep the backlog from increasing due to new proposals until the backlog has reached our equilibrium goal of about 3 years/hall, the PAC will continue to receive guidance for all three Halls that the basic beam time allocation (exclusive of proposals up for jeopardy review) will be that no more than 2/3 of the equilibrium level of beam time be recommended for approval (Note that our current level of operations corresponds to about three months of running per hall or 1-1/2 months of 100% efficient operation; therefore, the nominal PAC allocation will be 30 days per hall). This guidance will not be so rigid as to preclude PAC consideration and recommendation of important new experiments and/or programs that cannot be accommodated within the nominal beam time limits, but any such exceptions will have to present a compelling scientific case.


The laboratory has a three-year Jeopardy Rule that is aimed at reducing the beamtime backlog. Jeopardy begins three years after a hall has begun taking data or three years after the proposal was approved, whichever is later. The jeopardy policy is intended to ensure that the ratings of all approved experiments continue to accurately reflect their scientific priority. It recognizes the fact that the scientific world doesn't stand still: theoretical developments and experiments elsewhere can affect the scientific interest in experiments here, and therefore their priority. It reinforces our goal of always identifying and running the best possible science program. Jeopardy also provides a fair and equitable mechanism to reduce the backlog of approved experiments to about three years, as recommended by the Users Group Board of Directors, the PAC, and the laboratory's Science and Technology Review Committee.

All PACs will consider both new proposals and resubmitted "jeopardy" proposals on an equal footing. This will clearly have the effect of "raising the bar" for experiment approval.

The jeopardy process has been in effect in Hall C since PAC 15, and began in Hall A with PAC 18 and in HallB with PAC 20. PAC 21 will complete the first round of jeopardy review in Hall B, and will consider all remaining experiments in the hall that are subject to the initial round of the hall jeopardy review due to the fact that they have not yet been completed or been scheduled to run to completion in three years since the start of physics in the hall. As was the case for the Hall B reviews at PAC 20, the run group jeopardy reviews will include two main items:

During the jeopardy review, the run groups can request:

Since Hall B is close to the "equilibrium" backlog, in that hall the total beamtime allocation given to PAC 21 will be equal to the 30 days "basic allocation" plus all of the sum of the previously approved time for experiments undergoing jeopardy review. Halls A and C remain too far from equilibrium, so for them we will retain the current rule that the total beamtime allocation that will be given to PAC 21 will correspond to the 30 days "basic allocation" mentioned above plus 1/2 of the sum of the previously-approved time for all of the experiments undergoing jeopardy review at that PAC. Conditionally approved experiments will be included in the sum. For purposes of assigning the PAC beamtime allocation we consider two cases for conditionally approved experiments: if the PAC assigned beamtime to a conditionally approved experiment, that allocation will be used; if the PAC has not yet allocated beamtime, a conditionally approved experiment will be assigned a beamtime of 22 days for purposes of this calculation (the average for all approved experiments).

We continue to work hard to improve the accelerator and hall operating availabilities in order to provide more useful beam time each year. This is one of the primary goals of both the Accelerator Operations group and the hall groups. We have requested incremental funding from DOE in support of this effort, and we have also asked DOE for the additional funding necessary to increase accelerator operations so that we can deliver more physics each year. Discussions on these issues are ongoing.


New Proposals

New proposals requiring beam energies up to 6 GeV will be reviewed by PAC 21.

Experiments with Similar Physics Goals

On your proposal cover sheet indicate any existing approved, conditionally approved, or deferred experiments that have physics goals similar to those in your proposal. In the text of your proposal, compare and contrast your proposal with respect to these proposals and experiments already considered or under consideration by previous PACs. Note that both one-page summaries and the full text for most proposals are available on-line at You may also contact User/International Liaison (see below) for copies of proposals.

The spokespersons for the experiments and proposals you have listed on your proposal cover sheet will receive copies of your proposal prior to the PAC meeting. They will be allowed to submit written comments that will then be passed on to the PAC with a copy provided to you. If you fail to identify a previously approved proposal with similar physics goals, the spokesperson for the previously approved proposal may request that final approval of your proposal be contingent on review by a subsequent PAC of the issues they want raised. If laboratory management agrees that the request has merit, the final approval of your proposal will be deferred until the following PAC has reviewed the situation.

Experiment Summaries

A summary of all approved and conditionally approved experiments can be found on line at: PAC reports can be found on line at:

Beam Time

The beam time request should be provided in some detail using the standard forms identified below. Do not request any contingency time as the scheduling process includes this time. The beam requirements and time request should include all of the time for the following activities: setup & installation; alignment; calibration; check out and testing without beam; commissioning with beam; physics measurements (list all currents, energies, targets target and experimental apparatus configuration changes, and [for Halls A and C] spectrometer angle changes); and decommissioning.


If your collaboration has an approved experiment, a conditionally approved experiment, or a deferred proposal and you would like to modify the physics goals, significantly change your running conditions, receive reconsideration of your scientific rating, or achieve full approval for a conditionally approved or deferred experiment, please submit an update. When an update is submitted, the PAC allocation for the relevant hall will be increased by two-thirds (2/3) of the previously-approved beam time for the experiment requesting the change, and then the update request will be considered on an equal footing with all new proposals and all jeopardy proposals submitted to that PAC. That is to say, in submitting an update requesting a change in a previously approved experiment, all of the previously approved beam time will be at risk. Note that this risk may be avoided by submitting a new proposal requesting time for additional physics measurements beyond those in the previously approved experiment, but the PAC review of the new proposal will have no effect on the PAC rating of the previously-approved experiment. Note also that the PAC may or may not choose to hear an oral presentation for updates depending on the scope of the proposed changes. Further note that once the first round of jeopardy has been completed the PAC allocation for an update proposal will be increased by the full amount of previously approved time for the experiment, rather than 2/3 of that time, as noted above.

Deferred Experiments

Deferred experiments must be updated within one year or they will be removed from future consideration.

Withdrawn Proposals

A category of "withdrawn" has been established for proposals that were approved by a previous PAC, haven't been run within three years of approval or the start of physics in the hall, and whose authors chose to withdraw the proposal rather than defend it at a jeopardy review. Withdrawn proposals shall be considered part of the public domain, and by withdrawing the proposal the authors have given up any "intellectual property rights" they have to the physics it covers. Any interested party, including the original authors may submit a new proposal covering the same physics to a future PAC.

Rejected Proposals

A proposal based on a previously rejected proposal is considered a 'new' proposal. Further, this 'new' proposal must include substantive changes that fully address the issues raised by the PAC that rejected it for it to be considered by the new PAC.


Letters-of-intent may be submitted to solicit the evaluation by the PAC of a new line of research before investing the large effort required to prepare a full proposal. In general, the letters-of-intent will involve either a major new experimental apparatus or extension of present beam properties. Letters-of-intent will be made public after receiving PAC appraisal in the same manner as full proposals. This means that the research program contained in them would enter the public domain; therefore, the letters-of-intent mechanism cannot be viewed as a means of "staking out territory." Rather, it provides experimenters with feedback at an early stage on the PAC's views on the scientific and technical merit of an idea that the experimenters intend to develop into a full proposal.

Due Date: New Proposals, Updates, and Letters-of-Intent

Proposals, Updates, and Letters-of-Intent for PAC 21 are due at the JLab User/International Liaison office by close of business Monday, December 3.

Jefferson Lab
User Liaison Office, MS 12B
12000 Jefferson Avenue
Newport News, Virginia


All submissions can be mailed or submitted electronically, electronic submissions are preferred. An electronic version must accompany all hard copies. Fax submissions are not acceptable.

All proposals and updates to be considered by PAC21 must also include a completed:

These forms are available at the url:

Procedures for Experiments

Procedures for experiments are provided at The procedures include the submission and re-submission of proposals, the PAC's scientific ratings and recommendations of Approval, Conditional Approval, Deferral or rejection, the Directors award of beam-time, the experiment preparation and scheduling processes, the associated Environment, Health and Safety reviews, the running of the experiments, the allocation of computational resources, and the publication of results including presentations at conferences.

Reference Material Hard Copies

If you would like any of the materials on the Web sent to you, please contact User/International Liaison via phone (757-269-7687), fax (757-269-7003) or e-mail (