Transverse effects of longitudinal wakefields at high dispersion

Conference · Mon May 17 00:00:00 EDT 1993 · Proceedings of International Conference on Particle Accelerators

DOI:https://doi.org/10.1109/pac.1993.309724· OSTI ID:1450118

Decker, Franz -Josef ^[1]

---

1. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

In high energy linear colliders the transverse beam emittance has to be preserved in order to achieve small interaction spots. Beams with trajectory offsets in cavities ex cite transverse wakefields which kick the tail of the beam leading to an undesired emittance growth. Here we will concentrate on the longitudinal wakefield creating an energy deviation ΔE_W within the beam. At high dispersion η the beam will be spread out corresponding to its initial (and/or correlated) energy spread ΔE_o, (or ΔE_rf) and is therefore very sensitive to energy changes. The energy variation ΔE_W will cause a transverse emittance blow up in the high dispersion regions. The effect can be eestimated by comparing the betatron size σ_x = $$\sqrt{βε}$$ with displacement Δx = ηΔE_W/E. Some kicks and displacements will compensate each other along the beam line. Simulation results are presented showing how much is really compensated and the final emittance contribution of this effect for the SLC Ring-TGLinac transport line. To minimize it, any vacuum pipe irregularities, like bellows, diameter steps, collimators, etc. should be smoothed or avoided at higher dispersion areas.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1450118
• Report Number(s): SLAC-PUB--6179; ISBN: 0-7803-1203-1
• Resource Type: Conference paper
• Conference Information: Journal Name: Proceedings of International Conference on Particle Accelerators
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS