Beam lifetime and beam brightness in ALS
Beam lifetime in ALS is dominated by the Touschek scattering. Measurements of lifetime in single-bunch mode with estimates of bunch dimensions obtained from undulator radiation data are consistent with expectations (t=1.8 hours at 1.25 mA per bunch). However, the lifetime is significantly longer in multi-bunch mode (t=ll hours at 400 mA per 320 bunches). This discrepancy has been traced to an increase in the momentum spread and bunch length in the beam caused by longitudinal coupled-bunch motions driven by higher-order modes in the rf cavities. The increased momentum spread leads to a significant degradation in the undulator spectral performance. Feedback stabilization of the coupled-bunch motion improves the spectral characteristics of the undulator beam at the expense of beam lifetime. We observe an increase of {approximately}200% in beam lifetime by operating at the betatron coupling resonance.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 108179
- Report Number(s):
- LBL-36440; CONF-950512-320; LSGN-195; ON: DE96000143
- Resource Relation:
- Conference: 16. Institute of Electrical and Electronic Engineers (IEEE) particle accelerator conference, Dallas, TX (United States), 1-5 May 1995; Other Information: PBD: Apr 1995
- Country of Publication:
- United States
- Language:
- English
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