Development of a new magnetic measurement bench for in-vacuum undulators

Abstract

Magnetic measurement benches are used to measure the magnetic feld profle of insertion devices such as undulators. A critical feature of these benches is the traversal of a measurement head such as a Hall probe through the undulator whilst keeping it perfectly centered, ensuring that the measurement obtained is not distorted by physical displacements of the probe during measurement. This paper presents a detailed novel design for a new magnetic measurement bench based on the SAFALI Hall probe positioning system, which facilitates the measurement as well as magnetic optimisation of the magnetic feld from inside of a vacuum chamber. The paper gives a brief introduction to in-vacuum undulators and describes the new developments in the magnetic measurement bench. The design of the electronics involved in the bench is then explained, including the wireless communication systems used to operate the bench. The reproducibility of magnetic feld measurements as well as the precision of the hall probe positioning are also discussed and presented.