Realistic modeling of a particle–matter-interaction system for controlling the momentum spread of muon beams

Abstract

The goal of the Muon g-2 Experiment is to measure the anomalous magnetic moment of the muon with a precision of 140 ppb; this is achieved by observing the polarization of muon decays in a precisely designed storage ring. Unfortunately, 90% of the injected beam is lost in apertures since it has a rms momentum spread that is an order of magnitude larger than the ring’s acceptance. In this study, we investigate the use of a wedge absorber for reducing the momentum spread of a muon beam. This technique relies on an interplay between ionization cooling and emittance exchange. We present the outcomes of tracking simulations and examine in detail the impact of the absorber length in reducing the momentum spread of the beam. Overall, we illustrate that the wedge has a positive impact on the Muon g-2 Experiment as it can increase the intensity of the storable beam. The technique discussed here may serve as an important a tool for momentum control of next generation secondary-beam-based experiments.