Measurement of the Orbit Response Matrix for the SIS18 Doublet Optics

TL;DR

This paper details the measurement of the Orbit Response Matrix for SIS18's doublet optics and demonstrates how a linear machine model can be fitted to the data using the LOCO algorithm, aiding in accelerator characterization.

Contribution

It presents the first measurement of the ORM for SIS18 at extraction energy and establishes a fitted linear model using the LOCO algorithm based on the measured data.

Findings

Measured ORM explicitly presented for SIS18

A linear machine model fitted to ORM data using LOCO

Comparison with previous measurements discussed

Abstract

This report describes the setup and results of a 2024 experiment on beam-based measurement of the Orbit Response Matrix (ORM) for the GSI Heavy Ion Synchrotron SIS18, characterising the standard doublet optics at extraction energy. The measured ORM is explicitly presented for reference. As an important outcome of this study, an effective linear machine model based on a MAD-X lattice could be established by employing the LOCO algorithm (Linear Optics from Closed Orbit), which fits free parameters in the model to match the measured ORM. The discussion compares the findings to previous measurements.