Commissioning and first results of the Fermilab Muon Campus

Stratakis, Diktys; Drendel, Brian; Morgan, James P.; Syphers, M.; Froemming, Nathan

doi:10.1103/physrevaccelbeams.22.011001

Cited by 12 publications

(9 citation statements)

References 15 publications

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“…The weighted-average value of the Run-2/3 data is R ′ µ (Run-2/3) = 0.00370730088(75) (26), where the first error is statistical and the second is systematic. This value is in excellent agreement with the adjusted Run-1 value R ′ µ (Run-1) = 0.0037073004( 16) (6). Assuming that the systematic errors are fully correlated between R ′ µ (Run-2/3) and R ′ µ (Run-1), we obtain the combined value of R ′ µ (Run-1/2/3) = 0.00370730082(68) (31).…”

supporting

confidence: 82%

See 1 more Smart Citation

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

Abi¹,

Albahri²,

Al-Kilani³

et al. 2021

Phys. Rev. Lett.

1,372

1,060

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We present a new measurement of the positive muon magnetic anomaly, a µ ≡ (gµ − 2)/2, from the Fermilab Muon g −2 Experiment based on data collected in 2019 and 2020. We have analyzed more than four times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of two due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω′ p , and of the anomalous precession frequency corrected for beam dynamics effects, ωa. From the ratio ωa/ω ′ p , together with precisely determined external parameters, we determine a µ = 116 592 057(25) × 10 −11 (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a µ (FNAL) = 116 592 055(24) × 10 −11 (0.20 ppm). The new experimental world average is aµ(Exp) = 116 592 059(22) × 10 −11 (0.19 ppm), which represents a factor of two improvement in precision.

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supporting

confidence: 82%

“…Our Run-1 publications describe the principle of the experiment, previous results, and experimental details [1][2][3][4]. The experiment uses 3.1 GeV/c polarized muons produced at the Fermilab Muon Campus [6]. Muons are injected into a 7.112 m radius storage ring that was moved, and significantly upgraded, from the BNL experiment [7,8].…”

mentioning

confidence: 99%

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

Abi¹,

Albahri²,

Al-Kilani³

et al. 2021

Phys. Rev. Lett.

1,372

1,060

View full text Add to dashboard Cite

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“…More specifically, a high-statistics run was carried out to investigate the emittance exchange efficiency as a function of the wedge angle and its maximum thickness. We assume that both dispersion and beta functions at the absorber match the ones from S 1 , namely D x ¼ −0.65 m, β x ¼ 2.3 m, and β y ¼ 6.9 m. We use a beam with a rms unnormalized emittance of 12.0 μm in both planes which is not far from our previous measurements [14,25]. Our results for ðC 2 H 4 Þ n are illustrated in Fig.…”

Section: Choice Of Locationmentioning

confidence: 99%

“…In this study we investigate a possible configuration of a wedge system along the Fermilab Muon Campus [14,15], the facility that produces and delivers a muon beam to the Muon g-2 Experiment. We show that with emittance exchange the resulting momentum spread of the postwedge beam is not only lower than conventional designs but also maintains its value through the passage into the ring, resulting in a considerable increase of stored muons.…”

Section: Introductionmentioning

confidence: 99%

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

Stratakis

2019

Phys. Rev. Accel. Beams

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A scheme is discussed for momentum selection and momentum-spread reduction for muon-based experiments. The concept relies on placing a wedge absorber at a point along a beam transport system with nonzero dispersion. The technique has direct relevance to precision-science experiments such as the Fermilab Muon g-2 Experiment as it can enhance the muon beam intensity and therefore minimize the statistical uncertainty of the anomalous magnetic moment measurement. This paper presents a theoretical and numerical study about the orientation, material, geometrical parameters, and performance of this wedge. Results suggest a considerable increase in muon intensity for the Muon g-2 Experiment, when the optimal wedge is introduced along the beam path.

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“…C. From muon injection to muon storage Muons from the Fermilab accelerator complex are created as follows. Bunches of 8-GeV protons strike a target in the AP0 building of the Muon Campus [15]. The average number of protons incident on the target per muon fill was 9.84 × 10 11 .…”

Section: B the Run-1 Datasetmentioning

confidence: 99%

Beam dynamics corrections to the Run-1 measurement of the muon anomalous magnetic moment at Fermilab

Albahri,

Anastasi,

Badgley

et al. 2021

Preprint

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This paper presents the beam dynamics systematic corrections and their uncertainties for the Run-1 dataset of the Fermilab Muon g−2 Experiment. Two corrections to the measured muon precession frequency ω m a are associated with well-known effects owing to the use of electrostatic quadrupole (ESQ) vertical focusing in the storage ring. An average vertically oriented motional magnetic field is felt by relativistic muons passing transversely through the radial electric field components created by the ESQ system. The correction depends on the stored momentum distribution and the tunes of the ring, which has relatively weak vertical focusing. Vertical betatron motions imply that the muons do not orbit the ring in a plane exactly orthogonal to the vertical magnetic field direction. A correction is necessary to account for an average pitch angle associated with their trajectories. A third small correction is necessary, because muons that escape the ring during the storage time are slightly biased in initial spin phase compared to the parent distribution. Finally, because two highvoltage resistors in the ESQ network had longer than designed RC time constants, the vertical and horizontal centroids and envelopes of the stored muon beam drifted slightly, but coherently, during each storage ring fill. This led to the discovery of an important phase-acceptance relationship that requires a correction. The sum of the corrections to ω m a is 0.50 ± 0.09 ppm; the uncertainty is small compared to the 0.43 ppm statistical precision of ω m a .

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Commissioning and first results of the Fermilab Muon Campus

Cited by 12 publications

References 15 publications

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

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

Beam dynamics corrections to the Run-1 measurement of the muon anomalous magnetic moment at Fermilab

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