The compact electron cyclotron resonance ion source KeiGM for the carbon ion therapy facility at Gunma University

A high-energy carbon-ion radiotherapy facility is under construction at Gunma University Heavy Ion Medical Centre (GHMC). Its design was based on a study of the heavy ion radiotherapy at the National Institute of Radiological Sciences (NIRS) in order to reduce the size and construction cost of the facility. A compact electron cyclotron resonance ion source (ECRIS) for Gunma University, called KeiGM, was installed in 2008. It is almost a copy of the prototype ECRIS Kei2 which was developed by NIRS; this prototype meanwhile produced over 1 emA of C4+ using C2H2 gas (660 W and 40 kV). The beam intensity of C4+ was 600 eA with CH4 gas (250 W and 30 kV). The beam intensity satisfies the required value of 300 eA