Energy Comparison of Room Temperature and Superconducting Synchrotrons for Hadron Therapy

The yearly energy requirements of normal conducting (NC) and superconducting (SC) magnet options of a new hadron therapy (HT) facility are compared. Special reference is made to the layouts considered for the proposed SEEIIST facility. Benchmarking with the NC CNAO HT centre in Pavia (Italy) was carried out. The energy comparison is centred on the different synchrotron solutions, assuming the same injector and lines in the designs. The beam current is more than a factor 10 higher with respect to present generation facilities. This allows efficient ’multi-energy extraction’ (MEE), which shortens the therapy treatment and is needed especially in the SC option, because of the slow magnet ramping time. Hence, power values of the facility in the traditional mode were converted into MEE ones, for the sake of a fair stepwise comparison between NC and SC magnets. The use of cryocoolers and a liquefier are also compared, for synchrotron refrigeration. This study shows that a NC facility operated in MEE mode requires the least average energy, followed by the SC synchrotron solution with a liquefier, while the most energy intensive solution is the SC one with cryocoolers.