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Title: Energy stability in recirculating, energy-recovering linacs in the presence of a FEL

Technical Report ·
DOI:https://doi.org/10.2172/10155322· OSTI ID:10155322
; ;  [1]
  1. Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs (free electron lasers). Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M{sub 56}, phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. An analytical model which includes amplitude and phase feedback, has been developed to study the stability of the system for small perturbations from equilibrium. The interaction of the electron beam with the FEL is a major perturbation which affects both the stability of the system and development of startup and recovery scenarios. To simulate the system`s response to such large parameter variations, a numerical model of the beam-cavity interaction has been developed which includes low level rf feedback, phase oscillations and beam loss instabilities and the FEL interaction. Agreement between the numerical model and the linear theory has been demonstrated in the limit of small perturbations. In addition, the model has been benchmarked against experimental data obtained during CEBAF`s high current operation. Numerical simulations have been performed for the high power IR DEMO approved for construction at CEBAF.

Research Organization:
Southeastern Universities Research Association, Inc., Newport News, VA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC05-84ER40150
OSTI ID:
10155322
Report Number(s):
DOE/ER/40150-368; ON: DE96006243
Resource Relation:
Other Information: PBD: [1996]
Country of Publication:
United States
Language:
English