Higher Order Mode Measurements in Superconducting Accelerating Cavities

Bldg. 24, Rm 200 (DESY, Hamburg)

Bldg. 24, Rm 200

DESY, Hamburg

Notkestrasse 85 22607 Hamburg GERMANY
Higher Order Modes (HOM) and wakefields are a major common concern for the beam dynamics in superconducting accelerators. At the TTF/FLASH facility at DESY in Hamburg, various measurements have been carried out during time, for the study of the HOMs, but also on their use for diagnostics. Some of the first measurements used an intensity-modulated beam to find single high impedance modes from the spectrum. The most recent measurements deal with using the HOM signals as beam position monitors. In an attempt to match future measurements to the requirements of various projects, such as the XFEL and the ILC, but also other projects using superconducting technology, this mini-workshop on HOM measurements in superconducting cavities is held. The tentative agenda is as follows: - review past measurements - review important HOM-related questions for the beam dynamics in superconducting accelerators (particularly ILC, XFEL), - present ideas for possible future measurements - review facilities where such measurements could possibly be carried out in the future, in addition to FLASH
  • Anton Labanc
  • Ben Spencer
  • Carl Beard
  • Christopher Glasman
  • Claire SIMON
  • Emma Wooldridge
  • Ian Shinton
  • Igor Zagorodnov
  • Leo Bellantoni
  • Nathan Eddy
  • Nicoleta Baboi
  • Rainer Wanzenberg
  • Roger Jones
  • Stephen Molloy
  • Vic Scarpine
  • Monday, 22 January
    • 09:00 09:20
      Welcome 20m
      Speaker: Dr Nicoleta Baboi (DESY)
    • 09:20 09:45
      HOM studies on the TESLA cavities with intensity-modulated beam 25m
      Speaker: Dr Nicoleta Baboi (DESY)
    • 09:45 10:10
      HOM based measurements of the beam trajectory and cavity alignment 25m
      Speaker: Dr Stephen Molloy (SLAC)
    • 10:10 10:35
      Measurement of beam tilt effects 25m
      Speaker: Kirsten Hacker (DESY)
    • 10:35 11:15
      break 40m
    • 11:15 11:40
      HOMs and mode rotation in the ILC main linacs 25m
      Speaker: Dr Roger M. Jones (Univ. Manchester)
    • 11:40 12:30
      Discussion 50m
    • 12:30 14:00
      lunch 1h 30m
    • 14:00 14:25
      Asymptotic and rms Kicks due to HOMs in 3.9 GHz cavity 25m
      Speaker: Dr Rainer Wanzenberg (DESY)
    • 14:25 14:50
      Wakefields in the 3rd harmonic cavities 25m
      Speaker: Dr Leo Bellantoni (FNAL)
    • 14:50 15:15
      Calculation of Modes in Cavity Structures 25m
      Speaker: Dr Martin Dohlus (DESY)
    • 15:15 15:55
      break 40m
    • 15:55 16:20
      Short range wakes of the couplers 25m
      Speaker: Dr Igor Zagorodnov (DESY)
    • 16:45 17:45
      Discussion 1h
  • Tuesday, 23 January
    • 08:00 09:30
      Visit to FLASH tunnel 1h 30m
    • 09:30 09:55
      Electrical axis measurement of fundamental and higher order modes in TESLA cavities 25m
      Speaker: Anton Labanc (DESY)
    • 09:55 10:20
      Future possibilities involving the narrow- and broad-band data acquisition setup at FLASH 25m
      Speaker: Dr Stephen Molloy (SLAC)
    • 10:20 10:45
      HOM BPM Signal Processing with FPGA Based Digitizers 25m
      Speaker: Dr Nathan Eddy (FNAL)
    • 10:45 11:15
      break 30m
    • 11:15 13:00
      Concluding discussion 1h 45m