ACHIP at SwissFEL - electron beam shaping with dielectric micro structures
BORIS DOI
Abstract
Particle accelerators are the workhorse not only for modern particle physics but also for many other scientific and medical applications. For example, at CERN, the success in exploring matter on the smallest scale is based on the large hadron collider, a 27- kilometer long circular accelerator. Impactful research in biochemistry and material science has been enabled by bright X-ray light sources such as free-electron lasers. They require accelerators on the kilometer-scale which are only available at national research facilities. Regarding medical applications, proton therapy is a successful method to fight tumors in the human body. However, the access to such complex and costly machines is limited to a fraction of humanity.
The size of the accelerator facilities in operation today is dominated by the achievable electric field gradients. During the recent century, the standard technology using metallic cavities driven by microwaves has been heavily optimized but is approaching a fundamental limit: The gradients cannot be increased beyond the vacuum breakdown limit. Plasma and dielectric accelerators are novel techniques that promise more compact and cost-efficient devices with extremely high field gradients.
This thesis focuses on diagnostics, technology and applications for dielectric electron accelerators. A new diagnostic for strongly focused electron beams has been developed: Nano-fabricated metallic wires were successfully used for phase space tomography with sub-micrometer resolution. This tool could be applied at other advanced accelerator research facilities operating with micrometer-scale beams. Furthermore, the applicability of dielectric accelerators for beam shaping at existing free-electron laser facilities has been investigated. A tunable dielectric wakefield structure has been designed and tested for passive beam shaping. This device could serve to prepare a desired longitudinal phase space for a specific free-electron laser mode. A theoretical study explores the use of a dielectric laser accelerator for pulse train generation at free-electron lasers.
The size of the accelerator facilities in operation today is dominated by the achievable electric field gradients. During the recent century, the standard technology using metallic cavities driven by microwaves has been heavily optimized but is approaching a fundamental limit: The gradients cannot be increased beyond the vacuum breakdown limit. Plasma and dielectric accelerators are novel techniques that promise more compact and cost-efficient devices with extremely high field gradients.
This thesis focuses on diagnostics, technology and applications for dielectric electron accelerators. A new diagnostic for strongly focused electron beams has been developed: Nano-fabricated metallic wires were successfully used for phase space tomography with sub-micrometer resolution. This tool could be applied at other advanced accelerator research facilities operating with micrometer-scale beams. Furthermore, the applicability of dielectric accelerators for beam shaping at existing free-electron laser facilities has been investigated. A tunable dielectric wakefield structure has been designed and tested for passive beam shaping. This device could serve to prepare a desired longitudinal phase space for a specific free-electron laser mode. A theoretical study explores the use of a dielectric laser accelerator for pulse train generation at free-electron lasers.
Date of Publication
2021
Year of graduation
2021
Theses Type
dissertation
Subject(s)
Language(s)
en
Author(s)
Hermann, Benedikt |
Faculty/Graduate School
Institute
Access(Rights)
open.access
Primary OA Publication
true