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Director’s Message on Beamtime in 2027

Dear ALS Community,

We are writing to share that the Department of Energy has officially approved a revised plan for the ALS-U project, and we want to provide you with the latest information on upcoming operating schedules and proposal calls leading up to the start of dark time.

As previously announced, we continue to plan for dark time to start no earlier than October 2027, lasting approximately 22 months. We also anticipate substantial user beamtime in 2027 and have revised our user proposal plans to include an additional call for new General User Proposals (GUPs) and beamtime requests (BTRs) on existing GUPs, with a September 2, 2026, deadline.

Upcoming user beam schedules:

  • 2026-2 Cycle (July–December): No beam in the second half of 2026. The ALS will shut down in early July through the end of the calendar year for the replacement of the switch station through which all power for the ALS accelerator comes.
  • 2027-1 Cycle (January–June): Several months of beam, anticipated to begin in January. Accumulator ring commissioning will require a month-long period in the spring without user operations. Following this, continued accumulator commissioning will require approximately six weeks of reduced user operations. During that time, the ALS will be shut down for approximately four days per week. The detailed cycle schedule will be announced in fall 2026.
  • 2027-2 Cycle (July–December): At least three months of beam, depending on final dark time start date. We will not have an extended shutdown in summer 2027. Detailed schedule anticipated in spring 2027.
  • Dark time: Dark time is planned to start no earlier than October 2027 and will last approximately 22 months.

Current proposal call plans:

  • September 2, 2026: We will accept new GUPs and BTRs for the 2027-1 January–June cycle. All new GUPs should be completed within the two cycles of beamtime offered in 2027.
    • Expiration Notice: GUPs with first cycles in 2024-1 and 2024-2 will expire before the 2027 cycles begin. Submit a new proposal to get beamtime in 2027-1.
    • BTR Submissions: GUPs with first cycles in 2025-1 and 2025-2 can submit BTRs to request time in 2027-1.
  • March 2027: We anticipate accepting only BTRs for the 2027-2 July–September cycle. We will not accept new GUPs in March 2027.
  • RAPIDD: The RAPIDD access path will be open in 2027 for urgent access requests and for experiments that can be finished within a single cycle. Contact the beamline scientist(s) to see if a RAPIDD proposal is appropriate for your experiment.
  • Existing Approved Programs (APs) will pause when the ALS goes dark and then will resume afterwards. We do not plan to issue calls for new APs before the dark time.

Please consult the Apply for Beamtime page of the ALS User Guide for more information, and direct any questions to alsproposals@lbl.gov.

Thank you for your continued engagement and partnership as we work to deliver an upgraded and renewed facility for the next generation of user science.

To stay informed, we encourage you to subscribe to our regular updates and visit our Operating Schedule and ALS-U Timeline & Facility Impacts pages. Please don’t hesitate to reach out to us with any questions.

Best regards,

Andreas Scholl, Interim ALS Director

Dimitri Argyriou, Interim ALS-U Project Director and ALS Director on leave