N. Baboi, DESY EuCARD WP10 Kick-off Meeting, 24 Mar HOM-couplers (pick-ups) HOMBPM - Overview Purpose: on-line measuring device for 1. beam alignment on the axes of the 3.9GHz cavities (& 1.3 GHz cavities) in FLASH (&XFEL&ILC) 2. measurement of beam position at the cavity locations Task: develop, build, test electronics for 3.9 GHz cavities interpret signals and integrate in control system measure cavity alignment HOM-couplers one at each cavity end enable monitoring the HOMs excited by beam

N. Baboi, DESY EuCARD WP10 Kick-off Meeting, 24 Mar HOMBPM - Motivation Beam alignment: wakefields/HOMs: excited by the beam  can lead to worse beam quality measure to reduce WF: beam alignment on the axes of the accelerating cavities particularly critical in the 3.9 GHz cavities Beam position measurement: cavities & HOM couplers exist  comes for free (no new vacuum component needed) dipole modes ~ beam offset

N. Baboi, DESY EuCARD WP10 Kick-off Meeting, 24 Mar HOM-BPMs at the TESLA Cavities in FLASH HOM-BPMs at 1.3GHz cav. use dipole mode at 1.7 GHz installed in 5 accelerating modules (40 cavities) calibration: with SVD technique −problem: unstable in time Beam alignment in modules routinely used in FLASH XFEL: plan to install in some 1.3 GHz and in all 3.9 GHz cavities Other studies cavity alignment in cryo-module beam phase measurement with monopole modes at ~2.4GHz

N. Baboi, DESY EuCARD WP10 Kick-off Meeting, 24 Mar Milestones and Deliverables DeliverablesDescription/titleNature 1 Delivery month Prototype of HOMBPM electronics and code to probe beam centering on 3.9 GHz cavitiesP Report on experimental method and codeR48 MilestonesDescription/titleNature 1 Delivery month HOM alignment for 3.9 GHz cavity electronics verification D Final reportR48 1=prototype; R=report

N. Baboi, DESY EuCARD WP10 Kick-off Meeting, 24 Mar Costs YearFTEs person-months Direct costsIndirect costs Total costs Reque sted EC Personnel Durable equipment Consumab le and prototype Travel Total direct Personnel Material and travel Total indirect (€) EU post- doc F DESY PDCT D=P+ IT= D+IR < D/3 FD+C+T Total

N. Baboi, DESY EuCARD WP10 Kick-off Meeting, 24 Mar Initial Planning YearDeadline (approx) Work Employ post-doc (0.5 FTE) Meeting at DESY Define requirements for HOMBPMs for 3.9GHz cavities Study HOMs in the 3.9GHz cavities at FLASH Design electronics & LO Meeting (where?) Test electronics Measurement alignment HOMBPM Calibration Milestone: Prototype HOMBPM-electronics Further tests of HOMBPMs and cavity alignment measurements Milestone: Final report