Pressurized rf cavities in ionizing beams

Abstract

A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf) test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to $S{F}_6$ and $O_2$ were measured.

15 pp

Cited by in corpus (5)

• Simulation of beam-induced plasma in gas-filled rf cavities
• Further searches of the Higgs scalar sector at the ESS
• Helical Six-Dimensional Muon Ionization Cooling Channel with Gas-Filled RF Cavities
• Simulation of plasma loading of high-pressure RF cavities
• Muon Colliders, Neutrino Factories, and Results from the MICE Experiment