0000000000414483
AUTHOR
Frank Fichtner
Coherent Smith-Purcell radiation for minimally invasive bunch length measurement at the subpicosecond time scale
Physical review accelerators and beams 24(4), 042803 (2021). doi:10.1103/PhysRevAccelBeams.24.042803
Beam parameter stabilization for the P2 experiment at MESA
Abstract The P2 Experiment at MESA (Mainz Energy-recovering Superconducting Accelerator) will measure the weak mixing angle via electron proton scattering at 155 MeV. The expected measured parity violation asymmetry will be about 40 ppb. This requires a high precision beam diagnostic and control system in order to minimize asymmetries that derive from helicity correlated fluctuations of the beam parameters. A control system for position and angle has been installed and tested at MAMI (Mainz Microtron) and the P2 precision requirements for determining the asymmetry and controlling the transverse beam parameters have been met.
Reducing the contribution of the photoemission process to the unwanted beam in photoelectron sources at accelerators
Negative electron affinity (NEA) GaAs photocathodes show different pulse responses depending on the wavelength of photoexcitation. The pulse response at 800 nm shows a long and relatively intense tail, whereas at 400 nm, a tail of similar shape but with an intensity lower by around two orders of magnitude is observed. We explain this behavior with the specific properties of NEA photocathodes and compare it with the response of a positive electron affinity photocathode.