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Characterization of Higher Order Modes in the MAX IV Active 100 MHz Cavities

Björklund Svensson, Jonas LU (2015) EITM01 20151
Department of Electrical and Information Technology
Abstract
In circular accelerators, and in storage rings in particular, charged particles are kept in a closed orbit for a very long time by means of a magnet lattice. When the particle beam is bent by the magnetic field it emits light, which decreases the particle beam energy by an amount equal to the radiated energy. Over many bends in the magnets and many turns in the machine, these relatively small energy losses amount to significant values, and so it is crucial to replenish this energy to keep the beam orbiting. In storage rings, such as the MAX IV rings, this is done with radio frequency (RF) cavities containing an oscillating electromagnetic field which, on average, restores the correct amount of energy each turn. However, the beam itself can... (More)
In circular accelerators, and in storage rings in particular, charged particles are kept in a closed orbit for a very long time by means of a magnet lattice. When the particle beam is bent by the magnetic field it emits light, which decreases the particle beam energy by an amount equal to the radiated energy. Over many bends in the magnets and many turns in the machine, these relatively small energy losses amount to significant values, and so it is crucial to replenish this energy to keep the beam orbiting. In storage rings, such as the MAX IV rings, this is done with radio frequency (RF) cavities containing an oscillating electromagnetic field which, on average, restores the correct amount of energy each turn. However, the beam itself can excite so-called higher order modes (HOMs) in the cavities which can ruin the beam stability if these HOMs happen to resonate well and have certain resonating frequencies. The aim of this thesis is to determine the different HOMs of the active 100 MHz cavities of the MAX IV storage rings, as well as the impact these have on the beam stability. (Less)
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author
Björklund Svensson, Jonas LU
supervisor
organization
course
EITM01 20151
year
type
H2 - Master's Degree (Two Years)
subject
keywords
light sources, synchrotron, higher order modes, longitudinal instabilities, instabilities, cavities, radio frequency, RF, Accelerators, particle accelerators
report number
LU/LTH-EIT 2015-444
language
English
id
5472876
date added to LUP
2015-06-17 08:49:02
date last changed
2015-06-18 14:04:26
@misc{5472876,
  abstract     = {In circular accelerators, and in storage rings in particular, charged particles are kept in a closed orbit for a very long time by means of a magnet lattice. When the particle beam is bent by the magnetic field it emits light, which decreases the particle beam energy by an amount equal to the radiated energy. Over many bends in the magnets and many turns in the machine, these relatively small energy losses amount to significant values, and so it is crucial to replenish this energy to keep the beam orbiting. In storage rings, such as the MAX IV rings, this is done with radio frequency (RF) cavities containing an oscillating electromagnetic field which, on average, restores the correct amount of energy each turn. However, the beam itself can excite so-called higher order modes (HOMs) in the cavities which can ruin the beam stability if these HOMs happen to resonate well and have certain resonating frequencies. The aim of this thesis is to determine the different HOMs of the active 100 MHz cavities of the MAX IV storage rings, as well as the impact these have on the beam stability.},
  author       = {Björklund Svensson, Jonas},
  keyword      = {light sources,synchrotron,higher order modes,longitudinal instabilities,instabilities,cavities,radio frequency,RF,Accelerators,particle accelerators},
  language     = {eng},
  note         = {Student Paper},
  title        = {Characterization of Higher Order Modes in the MAX IV Active 100 MHz Cavities},
  year         = {2015},
}