Pressurized Gas Beam Monitor for Extremely High Intensities

Intense neutrino beam facilities for fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and LBNO at CERN, require hadron monitors to diagnose primary and secondary beam qualities. Existing beam monitors based on ionization chambers are not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. A novel pressurized gas-filled RF-resonator beam monitor is proposed that will be simple and radiation robust in high-radiation environments. Charged particles passing through the resonator produce ionized plasma, which changes the permittivity of the gas and the resonant frequency of the cavity. Radiation sensitivity is adjustable using gas pressure and RF amplitude. The beam profile will be reconstructed using X, Y, and U hodoscopes using strip-shaped gas resonators. The performance of a gas-filled RF resonator will be numerically simulated to evaluate the sensitivity of permittivity measurements and the effectiveness of calibration strategies. An entire resonator-hodoscope system will be designed and a demonstration test prepared. The pressurized gas-filled RF resonator beam monitor can be used in any extremely high radiation environment. The immediate applications include research facilities that create intense neutrino beams LBNF at Fermilab, T2K at KEK, and LBNO at CERN) and neutron spallation sources SNS at ORNL, ESS in Sweden, and the CSNS in China). Future uses include Accelerator-Driven Subcritical Reactors ADSR), which have been proposed for improved safety, waste management, plutonium disposition, and greenhouse gas reduction.