Two electron cyclotron resonance (ECR) ion sources were manufactured for the accelerator facility at the Hyogo Ion Beam Medical Center. H2+, He2+, and C4+ were chosen as the accelerating ions because they have the highest charge to mass ratio among ion states which satisfy the required intensity and quality. The sources have the same structure as the 10 GHz ECR source at the Heavy Ion Medical Accelerator in Chiba except for a few improvements in the magnetic structure. Their performance was investigated at the Sumitomo Heavy Industries factory before shipment. The maximum intensity was 1500 μA for H2+, 1320 μA for He2+, and 580 μA for C4+ at the end of the ion source beam transport line. These are several times higher than required. Sufficient performance was also observed in the flatness and long-term stability of the pulsed beams. These test results satisfy the requirements for medical use.

The Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences (NIRS) is not only dedicated to cancer therapy, it is also utilized with various ion species for basic experiments of biomedical science, physics, chemistry, etc. Two electron cyclotron resonance (ECR) ion sources are installed for production of gaseous ions. One of them, the NIRS-ECR, is a 10 GHz ECR ion source, and is mainly operated to produce C4+ ions for daily clinical treatment. This source realizes good reproducibility and reliability and it is easily operated. The other source, the NIRS-HEC, is an 18 GHz ECR ion source that is expected to produce heavier ion species. The output ion currents of the NIRS-ECR and the NIRS-HEC are 430e μA for C4+ and 1.1e mA for Ar8+, respectively.

A He gas-phase ion source having a three-electrode acceleration lens that can change the acceleration energy and magnification independently was developed. This source allows application of acceleration voltages up to 100 kV and extraction voltages up to 30 kV. This source is a component of our final objective of development, a nanometer lithography system with a beam diameter of 10 nm and a beam energy of 100 keV. In the present experiment, by using this source, the characteristics of He ion current emitted from W (111) emitter cooled by liquid N2 or liquid He was obtained. Maximum angular intensities of 40 nA/sr and 2.2 μA/sr were obtained at emitter temperatures of ∼100 and 20 K, respectively. In addition, the increase of the gas-phase ion current by emitter treatment (field-emission treatment or field-evaporation treatment) was ascertained.