Alex

Single Key image

Alex's research focuses on novel methods of electron beam phase space manipulation. In accelerator science, arbitrary control of a beam's 6D phase space would allow for the tailoring of a beam's characteristics for specific applications, improving system performance in any context (experimental, industrial, medical, etc.).
His Master's project topic was control of time-energy correlations using transverse deflecting cavities and specialized drift sections called negative identity drifts. This method is beneficial in its cost-saving ability and avoids the drawbacks of conventional chirp control methods. His current work is designing a feedback control system for the generation of arbitrary phase space correlations. Such a feedback control system would allow for automatic, real-time beamline adjustments without operator intervention.
His work is largely computational, using the General Particle Tracer particle tracking code and simulating beam transport in Python. Analytical methods are also often incorporated to understand the behavior of a particular beamline and for finding numerical solutions to beamline element settings.

Conventionally, a beam's time-energy correlation (chirp) is adjusted by off-crest acceleration in radiofrequency accelerating cavities. However, this method may increase building and operating costs depending on where in a beamline the chirp needs to be adjusted. An alternative method of chirp control using transverse deflecting cavities (TDCs) was proposed as a specialized chirp control method that could be cheaper and more efficient than chirping via off-crest acceleration.

A TDC-based chirper mixes a beam's transverse and longitudinal parameters to adjust chirp, though it can only impart a positive time-energy correlation adjustment (chirping). Converting the drift sections to negative identity drifts allows for a negative time-energy correlation adjustment (dechirping).

An analysis of this beamline was done using General Particle Tracer and matrix-based tracking in Python, resulting in identification of the largest source of beam quality degradation and related mitigation strategies. Work was also done to determine how sensitive key beam parameters (chirp, average position, and beam quality) were to realistic operating conditions.

To generate arbitrary phase space correlations, periodic arrays of magnets (wigglers) can be used to change a beam's momentum sinusoidally based on horizontal position. A series of wigglers can then act as building blocks for generating a desired position-momentum correlation. The resulting correlation can be measured with the projection method, which maps the horizontal phase space to a scintillating screen using a mm-scale slit, a skew quadrupole, and an upright quadrupole.

Realistic operating conditions mean that the actual settings of each wiggler (particularly vertical spacing and horizontal offset) may differ from the ideal settings. A comparison must be made between the measured phase space image and what the ideal phase space is expected to look like so that wiggler parameters can be adjusted as needed during operation. Based on the differences between the projected ideal and actual phase space images, a feedback control system is being designed to automatically update wiggler parameters. This feedback control system would remove the need for monitoring and updating by an operator, thus streamlining the experimental process.

Any relevant publications if you have