Cavity Alighment Using Beam Induced Higher Order Modes Signals in the TTF Linac
Each nine cell superconducting (SC) accelerator cavity in the TESLA Test Facility (TTF) at DESY [1] has two higher order mode (HOM) couplers that efficiently remove the HOM power [2]. They can also provide useful diagnostic signals. The most interesting modes are in the first 2 cavity dipole passbands. They are easy to identify and their amplitude depends linearly on the beam offset from the cavity axis making them excellent beam position monitors (BPM). By steering the beam through an eight-cavity cryomodule, we can use the HOM signals to estimate internal residual alignment errors and minimize wakefield related beam emittance growth. We built and tested a time-domain based waveform recorder system that captures information from each mode in these two bands on each beam pulse. In this paper we present a preliminary experimental study of the single-bunch generated HOM signals at the TTF linac including estimates of cavity alignment precision and HOM BPM resolution.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 878869
- Report Number(s):
- SLAC-PUB-11190; TRN: US0602636
- Resource Relation:
- Conference: Contributed to Particle Accelerator Conference (PAC 05), Knoxville, Tennessee, 16-20 May 2005
- Country of Publication:
- United States
- Language:
- English
Similar Records
Submicropulse electron-beam dynamics correlated with short-range wakefields in Tesla-type superconducting rf cavities
Higher-Order-Mode Effects in Tesla-Type Superconducting RF Cavities on Electron Beam Quality