PhD completed – Anna Vnuchenko
On 19 June 2020, OMA Fellow Anna Vnuchenko successfully defended her PhD thesis. Her doctoral thesis was evaluated during the act of defence which took place in a public session online due to the COVID pandemic. Despite these obstacles, the defense was successful and the thesis received a special mark of honour: “Cum laude”.
The title of Anna’s work is “High-gradient issues in S-band rf accelerating structure for hadron therapy accelerators and radio frequency quadrupoles”. This OMA project was hosted by CSIC/IFIC – Instituto de Fisica Corpuscular in Spain. Anna has been a student in the Faculty of Physics - Department of Applied Physics and Electromagnetism at University of Valencia.
Anna’s thesis focused on the study of high-gradient limitations in normal conducting radio-frequency (rf) accelerating structures. It has a focus on rf vacuum breakdowns that occurs due to the high electromagnetic fields found in such structures. Her thesis describes in detail the achieved performance and long-term behaviour of different types of accelerating structures, including RFQs that can be used for medical accelerators. Her work has demonstrated that an all-linac facility for hadron therapy based on high-gradient technology is now a perfectly feasible approach.
Her work also gave important indications about the main characteristics required by state-of-the-art test benches. Her R&D will no doubt be very useful for future studies into breakdown behavior of various accelerating structures.
Research in this area continues after the end of her OMA project in collaboration between IFIC-CSIC, the CERN RF CLIC group and CERN’s knowledge transfer group. Her experimental work related directly to high-gradient testing of a medical linac structure designed for proton therapy and results have recently been published in the journal Physical Review Accelerators and Beams.
Following onto her OMA Fellowship, Anna now continues her scientific career as a Fellow at CERN where she is working on the optimization of the negative ion source for CERN’s LINAC4.
A. Vnuchenko, et al., “High-gradient testing of an S-band, normal-conducting low phase velocity accelerating structure”, Phys Rev AB 23, 084801. https://doi.org/10.1103/PhysRevAccelBeams.23.084801