The Brookhaven muon (g−2) storage ring high voltage quadrupoles

For g-2/EDM precise measurements, a magnet, with a very homogeneous (±0.1 ppm) 3.0 T magnetic field in cylindrical muon storage volume (MSV: 0.333 m radius with 3.0 cm thickness and 10.0cm height) and without negative radial field B R in the spiral injection region (Z > 0.0 cm), is necessary. A design method of magneto-motive force (coil blocks (CBs) and iron-yoke with poles) placements, developed for MRI magnets, has been applied. Candidate placements are calculated under superconducting limitations. The two-dimensional (2D) placements are determined by tuning SVD (singular value decomposition) eigenmode strengths and the SVD is applied on a response matrix from magneto-motive forces to the magnetic fields in the muon storage region. Magnetic field ripples in the azimuthal direction are minimized. The candidate has five CBs and an iron-yoke with center iron-poles and satisfies the specifications.

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“…We can expect that the decay rate is less than 0.01 ppm/hour. This rate is smaller than the time variations in the other experiments [16,17].…”

Section: Specifications and Design Baselinesmentioning

confidence: 55%

Magnetic Design of a Superconducting Magnet for Muon g-2/EDM Precise Measurements in a Cylindrical Volume with Homogeneous Magnetic Field

Abe

Iinuma

Murata

et al. 2019

Proceedings of the 3rd International Symposium of Quantum Beam Science at Ibaraki University "Quantum Beam Science in Biology A

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“…In these simulations, a 3 kV RF voltage was applied to one 3.2 m azimuthal quadrupole section. The electric quadrupole plates have a cross section of 10×10 cm 2 [18]. In the proposed employment in the g −2 storage ring, RF with a voltage amplitude of ∼ 0.5 kV will be applied to all eight quadrupole sections, covering 43% of the ring circumference.…”

Section: Simulations Of the Rf Reduction Methodsmentioning

confidence: 99%

Reduction of coherent betatron oscillations in a muon g − 2 storage ring experiment using RF fields

et al. 2020

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The muon g − 2 experiments store a beam of polarized muons in a weak focusing storage ring. As the ensemble of muons goes around the ring, their spin precesses, and when they decay through the weak interaction: µ + → e + νeνµ the decay positrons are detected by electromagnetic calorimeters. In addition to the expected exponential decay in the positron time spectrum, the weak decay asymmetry causes a modulation in the number of positrons in a selected energy range at the difference frequency between the spin and cyclotron frequencies, ωa. This frequency is directly proportional to the magnetic anomaly a = (g − 2)/2, where g is the gyromagnetic ratio of the muon, which is slightly greater than 2. The detector acceptance depends on the radial position of the muon decay, so the coherent betatron oscillations of the muon bunch following injection into the storage ring amplitude modulates the measured muon signal with the frequency ωCBO. Applying radio frequency (RF) electric fields has the potential to significantly decrease the beam CBO, and additionally to scrape the beam to reduce muon losses from the storage ring during the measurement period. Preliminary tests showed significant CBO amplitude reduction.

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“…Figure 2.2 shows the equipotential contours of the electrostatic quadrupole fields. Together, the storage ring's magnetic field and the electrostatic quadrupole field provide restoring forces in both the vertical and radial directions [37,47].…”

Section: Storage Ring and Electrostatic Quadrupolesmentioning

confidence: 99%

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

Fienberg

2019

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The E989 Muon g − 2 Experiment aims to measure the anomalous magnetic moment of the muon, a µ , to an unprecedented precision of 140 parts per billion (ppb). There currently stands a greater than 3σ discrepancy between the best measurement of a µ and its theoretical value predicted using the Standard Model. The E989 experiment seeks to either resolve or confirm this discrepancy, which is suggestive of new physics interactions within reach of many contemporary experiments. To achieve the E989 target precision, the anomalous precession frequency, ω a , of muons in a magnetic storage ring must be determined with a systematic uncertainty below 70 ppb. This frequency is imprinted on the time-dependent energy distribution of decay positrons observed by 24 electromagnetic calorimeters. These calorimeters feature a novel design optimized expressly for the stringent demands of the ω a measurement. This dissertation outlines the motivation for and measurement principles behind E989, discusses the requirements, prototyping, testing, commissioning, and operations of the electromagnetic calorimeters, and presents a preliminary, blinded analysis of data

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The Brookhaven muon (g−2) storage ring high voltage quadrupoles

Cited by 48 publications

References 11 publications

Magnetic Design of a Superconducting Magnet for Muon g-2/EDM Precise Measurements in a Cylindrical Volume with Homogeneous Magnetic Field

Magnetic Design of a Superconducting Magnet for Muon g-2/EDM Precise Measurements in a Cylindrical Volume with Homogeneous Magnetic Field

Reduction of coherent betatron oscillations in a muon g − 2 storage ring experiment using RF fields

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

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