New Results from the Muon g-2 Experiment
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Engineering topics
Mott, James
Publications and source records attributed to Mott, James.
Beam-Based Diagnostics of Electric Guide Fields and Lattice Parameters for Run-1 of the Muon g-2 Storage Ring at Fermilab
A portion of the Muon g-2 Storage Ring electric system, which provides vertical beam focusing, exhibited an unexpected time dependence that produced a characteristic evolution of the stored beam during Run-1 of the Muon g-2 Experiment at Fermilab (E989). A method to reconstruct the Run-1 electric guide fields has been developed, which is based on a numerical model of the muon storage ring and optimization algorithms supported by COSY INFINITY. This method takes beam profile measurements from the Muon g-2 straw tracking detectors as input, and it produces a full reconstruction of the time-dependent fields. The fields can then be used for the reproduction of detailed beam tracking simulations and the calculation of ring lattice parameters for acceptance studies and systematic error evaluations.
43 PARTICLE ACCELERATORS↗
The Muon g-2 experiment at Fermilab
Precision measurements of the anomalous magnetic moment of the muon a are a stringent test of the Standard Model. The last measurement of a at Brookhaven National Laboratory (BNL) diers from the Standard Model prediction by 3-4: a possible indication of new physics. A successor to that experi- ment has been constructed at Fermilab, with the aim of reducing the experimental uncertainty by a factor of four to 140 ppb. The measurement technique continues to use the storage ring concept from BNL, with muons circulating in a highly uni- form magnetic dipole eld. The spin precession frequency is extracted by analysing the modulation of the rate of higher-energy positrons from muon decays, which are detected by 24 calorimeters around the inside of the ring. Compared to the previous experiment, signicant improvements have been made in the areas of muon beam preparation, storage ring hardware, eld measuring equipment, and detector and electronics systems. In these proceedings, I report on the status of the experiment as of June 2018, presenting an overview of the experiment's progress, some initial data from the rst run, and the anticipated timeline for a new result.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Muon Beam Dynamics and Spin Dynamics in the g-2 Storage Ring
The goal of the new g-2 experiment at fermilab is a measurement of the anomalous magnetic moment of the muon, with uncertainty of less than 140 ppb. The experimental method is to store a beam of polarized muons in a storage ring with pure vertical dipole field and electrostatic focusing, and to measure the precession frequency. Control of the systematics depends on unprecedented knowledge of the details of the phase space of the muon distribution. That knowledge is derived from direct measurements with scintillating fiber detectors that are inserted into the muon beam for diagnostic measurements, traceback straw tube tracking chambers, as well as the calorimeters that measure energy, time and position of the decay positrons. The interpretation of the measurements depends on a detailed model of the storage ring guide field. This invited talk presents results of studies of the distribution from the commissioning run of the experiment.
43 PARTICLE ACCELERATORS↗
Low-background tracker development for SuperNEMO
The SuperNEMO experiment will search for neutrinoless double beta decay (0νββ) with a target sensitivity of T{sub 1/2}(0ν) > 10{sup 26} years, corresponding to an effective neutrino mass of 50-100 meV. At its heart there is a low-background gaseous tracking detector which allows for extremely efficient background rejection and, if 0νββ is observed, may provide important insights into the mechanism via which it may be mediated. Radon inside the tracker, which can mimic rare ββ events, is one of the most dangerous backgrounds for SuperNEMO. To reach the target sensitivity the radon concentration inside the tracking volume must be < 0.15 mBq/m{sup 3}. To reach this challengingly-low level of radon, a considerable program of R and D has been undertaken. This includes automation of the tracker-wiring process, development of a dedicated setup to measure radon diffusion and a 'radon concentration line' which will be able to measure levels of radon in the μBq/m{sup 3} range.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗