Drive Beam Working Group Meeting - 10 TeV Collider Study

Tuesday 18 Feb 2025, 12:00 → 13:00 America/Los_Angeles

Zoom

Philippe Piot (Argonne National Laboratory)

Kickoff Meeting of the Drive Beam Working Group

drive-beam_PP_20250218_kickoff-discussion.pdf

Items discussed:

• The drive-beam accelerator represents a significant cost component of a collider.
• In principle, the drive-beam energy and charge are optimization parameters. Several projects, including CLIC and more recently HALHF, have optimized these parameters to achieve a cost-effective design. The current HALHF design utilizes a 4 GeV drive beam with 8-nC bunches. While transverse emittance requirements are generally relaxed (e.g., 100 µm for HALHF), they depend on the specific wakefield acceleration (WFA) channel and beam energy.
• Beam stability requirements have not been explicitly discussed. Transverse tolerances are typically expressed in terms of an "effective emittance," as off-axis injection can excite higher-order modes (HOMs) and seed beam breakup (BBU) or hose instabilities.
• As a first step, a table summarizing the drive-beam requirements assumed in the current 10-TeV design presented at Snowmass 2022 should be prepared.
• It was suggested that cost per delivered power should also be considered as a key metric, as it could provide a useful basis for comparing different designs—including both beam-driven and laser-driven concepts—on equal footing.
• Additional discussions are needed on two-beam acceleration (TBA), which is applicable to structure-based wakefield acceleration (SWFA) only, and on strategies for generating a large number of bunches at a high repetition rate.

Action items:

• prepare table for everybody input (PP)
• prepare two paragraphs for mergin in the ESPP input
• plan discussion on energy.charge choice for the drive beam (should do this exercise in parallel for PWFA, SWFA (CWA) and SWFA (TBA)