Development of a Real-Time Magnetic Field Measurement System for Synchrotron Control

Abstract

The precise knowledge of the magnetic field produced by dipole magnets is critical to the operation of a synchrotron. Real-time measurement systems may be required, especially in the case of iron-dominated electromagnets with strong non-linear effects, to acquire the magnetic field and feed it back to various users. This work concerns the design and implementation of a new measurement system of this kind currently being deployed throughout the European Organization for Nuclear Research (CERN) accelerator complex. We first discuss the measurement principle, the general system architecture and the technology employed, focusing in particular on the most critical and specialized components developed, that is, the field marker trigger generator and the magnetic flux integrator. We then present the results of a detailed metrological characterization of the integrator, including the aspects of drift estimation and correction, as well as the absolute gain calibration and frequency response. We finally discuss the latency of the whole acquisition chain and present an outline of future work to improve the capabilities of the system.

Drift-Free Integration in Inductive Magnetic Field Measurements Achieved by Kalman Filtering

“…In particle accelerator applications such as iron-dominated synchrotron magnets, real-time monitoring of the magnetic field is critical for the control of the particle beam, and a very demanding accuracy of the order of a few 10 T is required. At CERN, this is realized by using the so-called B -train systems where integrator drift correction was implemented by using short integration periods (maximum of a few seconds) combined with reference markers based on Nuclear Magnetic Resonance (NMR) or Ferrimagnetic Resonance (FMR) technology [ 12 , 13 , 14 , 15 ]. In this manner, a drift of about 2.3 ppm/s over a time scale of 1–2 s is achieved.…”