CERN has developed a new fast pulsed septum magnet to replace the aging PS proton extraction septum. The aim is to increase the refurbishment intervals of the magnet and to phase out the old power converter, while allowing energy savings during operation. The new system includes a novel under vacuum eddy current septum magnet, a new third-harmonic fast pulse generator and dedicated control system with post pulse fault analysis for achieving the required flat top precision. This paper will briefly describe the system development and focus on the lessons learned from its construction and report the results of the testing phase.

SCK CEN is developing MYRRHA, a large-scale Accelerator Driven System. MYRRHA shall be a subcritical nuclear reactor driven by a high-power linear proton accelerator, which sustains the nuclear reaction. In the initial phase, known as the MINERVA project, the goal is to demonstrate the high reliability requirements on the accelerator. The two primary end users of the MINERVA project are the Full Power Facility and the Proton Target Facility. In collaboration with SCK CEN, CERN studied and designed an extraction septum for the 100 MeV Proton Target Facility. Two distinct topologies have been evaluated magnetically and tracked particle simulations have been executed to validate the designs. A preferred low-power solution has been retained for a subsequent detailed design. A final magnetic verification to confirm the mechanical design requirements has been carried out. This has allowed to develop a detailed 3D mechanical design including all manufacturing tolerances required for subcontracting the magnet fabrication to the industry. This article covers the 2- and 3-dimensional magnetic modelling, the tracked particle simulations and the mechanical design of the septum magnet.

The quality of slow extraction from the SPS (Super Proton Synchrotron) to the North Area is critically influenced by the straightness tolerance of the electrostatic septum. Past observations have identified a degradation of the anode body straightness, resulting in an increased beam loss during ex- traction. A new metrology bench including optical sensors has been developed to cope with the tolerance requirements while also allowing process automation. Two distinct mea- surement procedures are currently employed: one for the anode noses and another for the individual wire metrology. A control system was developed to automate the metrology and analysis process, allowing operator and time-independent measurements and increasing process accuracy. The find- ings from these investigations provide accurate information in case corrective machining of the anode body is required. The metrology method and the described nose scan approach will further reduce beam loss during the slow extraction pro- cess.

The impact of high-flux protons on beam loss during slow extraction from the SPS to the North Area has been discussed, and improvements have been proposed focusing on reducing activation, lifetime reduction, and anode body distortion. The conducted studies shall demonstrate the feasibility of replacing the stainless-steel tank, flanges, and anode body with low-Z materials. A reduced-length prototype was fabricated to demonstrate mechanical, electrical, and vacuum performance. The paper presents the vacuum vessel development from the reduced-length prototype to the full-length setup, including numerical analysis. Prototype qualification tests, including vacuum performance, leak-tightness, high-voltage feedthrough performance, and deformation during evacuation, will be discussed to confirm that the tank remains within predicted non-linear buckling limits.