[Cuga] Experiment Schedule change upcoming - a message from Rolf Ent and Andrei Seryi

[Lorelei Carlson]

Dear Jefferson Lab User Community,

This is to announce an upcoming change in the posted schedule. Whereas the detailed schedule update may take us 2-3 weeks to work out, at highest level our planning is as follows:


1)      To compensate for the unexpected difficult startup of low-energy, multi-Hall CEBAF operations, together with recovery from power outages, we plan to extend the Summer Run with three weeks for Halls A and B, up to September 9, 2019.



2)      We plan to add 2 weeks to the accelerator down following the Summer Run to enable needed facility maintenance and to implement the elements of the energy reach planned. The latter aims at restoring a balanced 1050/1050 MeV/linac capability and executing the planned Fall 2019 and Spring 2020 physics program at its scheduled energy. This follows our plan for eventually reaching 12 GeV capabilities in the out-years.



3)      The start of physics operations in the Fall 2019 schedule would then be on November 25, 2019, before Thanksgiving. Our plan is to run the experiments as on the posted schedule, CREX in Hall A, Run Group B in Hall B, the polarized Helium-3 experiments in Hall C, and GlueX Phase II in Hall D.



4)      We will stop the 2019 CEBAF operations early morning of December 20, 2019, and keep the accelerator in "Power Permit" mode over the Christmas Break. This is to expedite the restoration of beam operations in 2020. Beam restoration will start January 3, 2020.



5)      The start of physics operations would be January 10, 2020, and we plan to continue the experiments mentioned above. Early February, Hall B would see a two-week changeover for installation of the BONuS12 experiment.



6)      Physics operations would stop as on the posted schedule on May 6, 2020, to allow for the installation activities related to the CHL-2K cold box.

We very much realize that this schedule imposes changes to the Hall planned schedules, and has a direct impact on some of the scheduled Nuclear Physics experiments, including loss of days and contingency, but we believe we honor the intent of the presently posted schedule. Please be aware that we are working on the detailed experiment schedule, as we still need to fold in various (short) periods where four-Hall beam operations are incompatible due to beam energy, current or polarization requirements, so the dates mentioned above may not be exact for all four Halls.


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