Analysis of Powering and Quench Protection of the SIGRUM Superconducting Combined-Function Dipole Magnet

In particle accelerators devoted to hadron therapy treatments, the magnet design plays an essential role in ensuring the safety of the patients under treatment. An incorrect setting or malfunctioning may cause damage to healthy tissues and cells. Due to their nature, superconducting magnets can undergo a drastic state-change, namely the quench. When it occurs, the magnetic field reduces quickly, causing the loss of control of the circulating beam in the accelerator. One of the reasons leading to a quench is that the temperature in the magnet is above critical values, which depend on the magnet design. Therefore, a complete thermal analysis is required to guarantee a safe operation of the magnets. This article aims to assess the impact of transitory losses on thermal transients in the demonstrator superconducting magnet for hadron therapy of the SIGRUM project. In order to validate the magnet thermal design, the simulation tools part of the Simulation of Transient Effects in Accelerator Magnets (STEAM) framework were leveraged. Several finite elements (FE) simulations were performed under different conditions. Furthermore, the transient following a quench was simulated with a finite differences code. This allowed us to design the magnet quench protection system, which is based on an energy-extraction system.