Topology optimization of ironless synchrocyclotrons

Cyclotrons are particle accelerators used in a wide range of applications, for example in physics or nuclear medicine. Their role in hadron therapy is especially very promising for the next decades. This type of radiation therapy consists in treating tumors by irradiation through accelerated ions. It offers many advantages over classical radiation therapy such as higher efficiency and more accurate covering of the tumor. A serious drawback encountered by cyclotron technology is the difficulty to vary the beam energy. The PSFC of the Massachusets Institute of Technology (MIT) developed several models of a new type of cyclotrons, the ironless synchrocyclotron, that could overcome this issue. This kind of cyclotron, as its name suggests, is designed without the heavy iron yoke traditionally used. This feature gives important advantages, the most important one being the possibility of having an output beam energy that is more easily variable. Indeed, without the presence of saturated iron, the magnetic field varies linearly with the current in the coils. By changing the current level, it will be possible to choose the beam energy. Several models have been developed but they have never been optimized in term of quantity of conductor. In this master thesis we develop a topology optimization tool for the design and the optimization of ironless synchrocyclotrons. The topology optimization tool is used to reduce significantly the conductor quantity of the model designed by the MIT. An ironless equivalent to the superconducting synchrocyclotron (S2C2) of Ion Beam Applications (IBA) is also developed. In addition, the layout of a potential conductor for this ironless S2C2 is proposed.