ABSTRACT

Over time, particle accelerators’ superconducting radiofrequency (SRF) cavities used to accelerate the particle beam degrade, causing higher x-ray field emission, excessive heating, and difficulty achieving previous performance capabilities. To keep particle accelerators running at optimal performance, a highly labor-intensive and expensive maintenance procedure involving complete disassembly, cleaning (via electro-polishing, high-pressure rinsing, high-temperature baking, etc.), and reassembly of the SRF cavities and associated cryomodule is conducted. During that time (typically 1-2 years), the overall accelerator performance is compromised, delivering lower energy and presenting opportunities for risk when removing and installing the cryostats.

An alternative method termed “in-situ plasma processing” is being investigated at low cost here at Argonne, in collaboration with MSU/FRIB, FNAL, IJCLab, JLab, and BNL to collectively understand the advantageous use of this method on SRF cavities in accelerators. Prior research by SNS, FNAL, FRIB, and JLab has established the efficacy of plasma processing in enhancing cavity performance within a matter of days. It is advantageous to pursue this method, allowing for possible use on modern ATLAS cryomodules, which exhibit low-efficiency behavior. This talk covers the fundamentals of in-situ plasma processing, results of efforts in ATLAS at Argonne, reference to recent progress within the collaboration, and future applications of this technique.