Beam-based alignment at the Cooler Synchrotron COSY as a prerequisite for an electric dipole moment measurement

TL;DR

This paper presents a beam-based alignment technique developed at COSY to precisely calibrate quadrupoles and BPMs, crucial for accurate electric dipole moment measurements in storage rings.

Contribution

It introduces a novel alignment method that improves quadrupole and BPM calibration accuracy, essential for EDM experiments.

Findings

Achieved approximately 40 micrometer alignment precision.

Developed a method based on beam deflection in quadrupoles.

Discussed implications for designing high-precision storage rings.

Abstract

The J\"ulich Electric Dipole moment Investigation (JEDI) collaboration aims at a direct measurement of the Electric Dipole Moment (EDM) of protons and deuterons using a storage ring. The measurement is based on a polarization measurement. In order to reach highest accuracy, one has to know the exact trajectory through the magnets, especially the quadrupoles, to avoid the influence of magnetic fields on the polarization vector. In this paper, the development of a beam-based alignment technique is described that was developed and implemented at the COoler SYnchrotron (COSY) at Forschungszentrum J\"ulich. Well aligned quadrupoles permit one to absolutely calibrate the Beam Position Monitors (BPMs). The method is based on the fact that a particle beam, which does not pass through the center of a quadrupole, experiences a deflection. The precision reached by the method is approximately 40 micro meter. Some consequences for the design of a new high precision storage ring for EDM mesasurements are discussed.