Walter Scott, Jr. College of Engineering

Graduate Exam Abstract

Christopher Hall
Ph.D. Preliminary
Nov 05, 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: