Mechanical Design of the PIP-II ORBUMP Pulsed Dipole Magnet

TL;DR

This paper details the mechanical design and analysis of the PIP-II ORBUMP pulsed dipole magnet, including core clamping, coil fabrication, and insulation performance to meet increased magnetic field and pulse rate requirements.

Contribution

It introduces a comprehensive mechanical design for the ORBUMP magnet, including finite element analysis and insulation testing, tailored for high-rate pulsed operation in the PIP-II upgrade.

Findings

Finite element analysis optimized core clamping to reduce deflection.

Water-cooled coil design ensures magnetic field homogeneity.

Virgin PEEK insulator exhibits reliable high voltage performance.

Abstract

The Proton Improvement Plan II (PIP-II) project is a vital upgrade to the Fermilab accelerator complex. The magnet pulse rate of the PIP-II Injection system requires an increase from the current rate of 15 Hz to 20 Hz as well as a roughly 30% increase in the magnetic field of the new Orbital Bump (ORBUMP) pulsed dipole magnets in the Booster. The ORBUMP magnet mechanical design is presented in this paper. The ORBUMP magnet is secured in a vacuum box and the core is made up of 0.127 mm thick, low carbon steel laminations with a C-5 inorganic magnesium phosphate coating. The core is clamped using external tie bars welded to the core end plates. ANSYS Finite Element Analysis (FEA) was used to evaluate the clamping design to minimize the deflection of the core post welding of the tie bars. The water-cooled, single turn coil, which shapes the magnetic field by acting as the pole tips, is critical for the integrated field homogeneity. The coil manufacturing tolerances and fabrication techniques were evaluated to ensure the magnetic properties of the magnet could be obtained. The coil is electrically isolated from the core using virgin Polyether ether ketone (PEEK) insulating material in the gap. An investigation into the high voltage performance of the virgin PEEK insulator was conducted via partial discharge testing using a 1:1 scale sample.