New method for a continuous determination of the spin tune in storage rings and implications for precision experiments

TL;DR

The paper introduces a novel, highly precise method for continuously determining the spin tune in storage rings, significantly improving control over particle spin motion crucial for electric dipole moment measurements.

Contribution

A new method for continuous spin tune measurement is developed and validated, achieving unprecedented precision levels in a storage ring environment.

Findings

Achieved spin tune determination with a precision of 10^{-8} in 2.6 seconds.

Extended precision to 10^{-10} over a 100-second cycle.

Demonstrated applicability for high-precision accelerator physics experiments.

Abstract

A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune - defined as the number of spin precessions per turn - is given by $\nu_s = \gamma G$ (gamma is the Lorentz factor, $G$ the magnetic anomaly). For 970 MeV/c deuterons coherently precessing with a frequency of ~120 kHz in the Cooler Synchrotron COSY, the spin tune is deduced from the up-down asymmetry of deuteron carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order $10^{-8}$, and to $1 \cdot 10^{-10}$ for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics: controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.