The Muon g-2 experiment (E989) at Fermilab is aiming at measuring the anomalous magnetic moment of the muon (aμ) at a precision of ∼140 ppb. aμ was measured at a precision of 540 part-per-billion (ppb) in the previous Muon g-2 experiment (E821), and its result deviated from the theoretical calculation by ∼3.7σ. This discrepancy is arguably the strongest existing hint for physics beyond the SM. The new experiment E989 will either confirm or resolve it. In this experiment, the muon anomalous precession angular frequency ωa and the magnetic field in which the muon precesses are measured. ωa is measured by detecting the decay positrons in 24 calorimeter stations, and the magnetic field is measured by Nuclear Magnetic Resonance (NMR) probes. In this seminar, I will give a detailed description of the high precision magnetic field measurement system and its analysis framework. The NMR frequency extraction methods and their implementation using GPU for fast online feedback will be highlighted. The overall performance of the magnetic field measurement system in Run1 and recent upgrades for Run2 will be discussed.

Host: Prof. Tim Gorringe