Vertical Septum Magnet Design for the APS Upgrade

Abstract

The vertical injection scheme proposed for the APS Upgrade (APS-U) Project requires a challenging septum magnet that must meet stringent beam physics, magnetic field leakage, and vacuum requirements. The current iteration of this magnet design includes an enlarged stored-beam chamber aperture of 9 mm x 12 mm and a reduction of the septum thickness to 1.5 mm. The enlarged aperture accommodates a non-evaporable getter (NEG)-coated stored beam chamber to better achieve the required vacuum. A prototype septum magnet has been built and measurements confirm the cancellation of a peak leakage field even though the value is six times larger than the design. The leakage field measured at the upstream (US) end cancels the downstream (DS) end as was expected by design. The measured and simulated leakage field and the stored beam trajectories are reported.