Graduate Exam Abstract

Christopher Hall

Ph.D. Preliminary
November 5, 2014, 1:00 pm - 3:00 pm
ERC B301
Analysis and Simulation of Collective Beam effects in an Energy Recovery Linac FEL Driver

Abstract: Free-electron lasers (FELs) serve as very high brilliance sources of radiation and are being used to perform research in a number of scientific areas. In the push for higher average power the energy recovery linac (ERL) presents a means of efficiently operating at very high repetition rates. However, ERLs present unique challenges in electron beam dynamics and machine design especially in the area of controlling collective effects in the electron bunches. Coherent synchrotron radiation (CSR) and longitudinal space charge (LSC) present severe challenges FEL efficiency and operation. In this work existing models of CSR and LSC are examined and utilized to perform an analysis of measurements collected on the Jefferson Laboratory ERL FEL driver. We then examine how this analysis differs between the commonly used 1-D CSR model and a much more computationally intensive 2- D model. Finally, we perform an analysis of the microbunching instability that results from LSC and CSR, examining its development in the arcs and compression chicane of the JLab FEL. In addition, looking at under what beam conditions are required for microbunching to develop and the overlaps between this parameter space and where the 2-D CSR model may be required to adequately explain CSR effects on the beam.

Adviser: Sandra Biedron
Co-Adviser: Stephen Milton
Non-ECE Member: William Fairbank, Physics
Member 3: Carmen Menoni, Electrical and Computer Engineering
Addional Members: N/A


Program of Study: