Ion-production efficiency of a singly charged ion source developed toward a 11C irradiation facility for cancer therapy

• Published in: Review of scientific instruments 2019-05, Vol.90 (5), p.053303-053303
• Main Authors: Katagiri, K., Wakui, T., Hojo, S., Boytsov, A. Yu, Donets, E. D., Donets, E. E., Ramzdorf, A. Yu, Noda, A., Shirai, T., Noda, K.
• Format: Article
• Language: English
• Subjects: Boron compounds; Cancer; Cancer therapies; Carbon dioxide; Cobalt; Efficiency; Electron beams; Ion sources; Ions; Irradiation; Isotope separation; On-line systems; Particle in cell technique; Positron emission; Proton beams; Scientific apparatus & instruments; Therapy
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.5090167

The ion-production efficiency of a newly developed singly charged ion source (SCIS) has been investigated to discuss the possibility of it being used in an isotope separation on-line system that provides 11C ions for heavy-ion cancer therapy with simultaneous verification of the irradiation field using positron emission tomography. The SCIS uses a low-energy hollow electron beam to produce singly charged carbon ions efficiently. To deliver sufficient 11C ions to the treatment room from a limited amount of 11C molecules, which are produced from a boron compound target and proton-beam irradiation via the 11B(p,n)11C reaction, the SCIS must have high ion-production efficiency. To realize this high efficiency, the SCIS was designed using a three-dimensional particle-in-cell code in previous work. With the fabricated SCIS, we performed experiments to measure the efficiency of producing CO2+ ions from nonradioactive 12CO2 molecules and C+ ions from nonradioactive 12CH4 molecules. We found that the SCIS achieved efficiencies of εC+=4×10−3 (0.4%) for C+ production and εCO2+=0.107 (10.7%) for CO2+ production.