Accelerator performance analysis of the Fermilab Muon Campus

Abstract

Fermilab is dedicated to hosting world-class experiments in search of new physics that will operate in the coming years. The Muon g-2 Experiment is one such experiment that will determine with unprecedented precision the muon anomalous magnetic moment, which offers an important test of the Standard Model. We describe in this study the accelerator facility that will deliver a muon beam to this experiment. We first present the lattice design that allows for efficient capture, transport, and delivery of polarized muon beams. We then numerically examine its performance by simulating pion production in the target, muon collection by the downstream beam line optics, as well as transport of muon polarization. We finally establish the conditions required for the safe removal of unwanted secondary particles that minimizes contamination of the final beam.

Commissioning and first results of the Fermilab Muon Campus

“…Figure 1 shows a schematic layout of the Fermilab Muon Campus. While a more detailed description of all beam lines can be found elsewhere [14], we will review here their main features. Protons with a kinetic energy of 8 GeV are delivered through the M1 beam line to an Inconel target [15] at AP0 and produce a beam of secondary particles that is most significantly composed of protons, pions, positrons, and deuterons.…”

Measuring the Precession Frequency in the E989 Muon g – 2 Experiment

“…Pion decays in the M2 and M3 lines are the primary source of muons in the particle beam delivered to the E989 experiment [37,48].…”

Application of passive wedge absorbers for improving the performance of precision-science experiments

“…This imposes several placement constraints since the Muon Campus has a series of tight bending and quadrupole sections, areas with elevation changes, as well as complicated injection and extraction schemes with closely packed instrumentation. Furthermore, the DR injection and DR extraction sections contain the narrowest apertures along all beam lines and therefore any upstream beam growth can significantly harm performance [5]. For this reason, we choose to place the wedge downstream of the extraction region, along the last horizontal bend string of the M5 line [see Fig.…”

“…Unlike our studies in Sec. III, where a priori assumption of the initial beam distribution was made, we start upstream of W 1 by using the actual distribution that is the outcome of an end-toend simulation from the target [5]. Our simulation was initialized at the upstream edge of Extraction C-Magnet (ECMAG) at S ¼ 0 and for simplicity there was no readjustment of the beam line optics downstream the wedge from the original settings.…”

“…In contrast, the line that delivers beam to the ring has a larger acceptance, i.e., σ=p m ¼ 1.26%. Results from numerical simulations [5,6], displayed in Fig. 1, predict that only 10% of the delivered muons have a momentum that is within 0.12% of p m .…”