Study of Abnormal Vertical Emittance Growth in ATF Extraction Line
Since several years, the vertical beam emittance measured in the Extraction Line (EXT) of the Accelerator Test Facility (ATF) at KEK, that will transport the electron beam from the ATF Damping Ring (DR) to the future ATF2 Final Focus beam line, is significantly larger than the emittance measured in the DR itself, and there are indications that it grows rapidly with increasing beam intensity. This longstanding problem has motivated studies of possible sources of this anomalous emittance growth. One possible contribution is non-linear magnetic fields in the extraction region experimented by the beam while passing off-axis through magnets of the DR during the extraction process. In this paper, simulations of the emittance growth are presented and compared to observations. These simulations include the effects of predicted non-linear field errors in the shared DR magnets and orbit displacements from the reference orbit in the extraction region. Results of recent measurements using closed orbit bumps to probe the relation between the extraction trajectory and the anomalous emittance growth are also presented.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1028688
- Report Number(s):
- SLAC-PUB-14684; TRN: US1105580
- Journal Information:
- Conf.Proc.C0806233:mopp003,2008, Conference: EPAC'08, 11th European Particle Accelerator Conference, 23-27 June 2008, Genoa, Italy
- Country of Publication:
- United States
- Language:
- English
Similar Records
Simulation Studies On The Vertical Emittance Growth At The Existing ATF Extraction Beamline
Simulation Studies on the Vertical Emittance Growth in the ATF Extraction Beamline