Systematic errors related to quadrupole misplacement in an all-electric storage ring for proton EDM experiment

TL;DR

This paper investigates how quadrupole misplacement in an all-electric proton storage ring can cause false EDM signals, analyzing the effects through simulations and proposing correction methods to mitigate this issue.

Contribution

It provides a detailed simulation study of quadrupole misplacement effects and introduces practical correction strategies for EDM experiments in all-electric storage rings.

Findings

Quadrupole misplacement causes significant false EDM signals.

Correction methods like RF tuning and weaker focusing quadrupoles are effective.

Proper control of quadrupole placement is critical for accurate EDM measurements.

Abstract

Misplacement of electrostatic elements can pose false EDM signal in a storage ring EDM experiment because of coupling between vertical electric field and magnetic dipole moment. A vertically misplaced quadrupole introduces electric field proportional to its misplacement, changing periodically in the particle's rest frame during the storage. This leads to accumulation of vertical spin component at every revolution. We investigated this effect by simulating a proton in an all-electric ring with several quadrupole scenarios. It turns out that the misplacement of quadrupoles is a critical item to keep under control, for which we propose several methods. These include tuning the frequency of the RF cavity, making use of additional correction quadrupoles and using quadrupoles with weaker focusing strength.