title: A study on prevention of an electric discharge at an extraction electrode of an electron cyclotron resonance ion source for cancer therapy.
abstract: A compact ECR ion source has utilized for carbon radiotherapy. In order to increase beam intensity with higher electric field at the extraction electrode and be better ion supply stability for long periods, electric geometry and surface conditions of an extraction electrode have been studied. Focusing attention on black deposited substances on the extraction electrode, which were observed around the extraction electrode after long-term use, the relation between black deposited substances and the electrical insulation property is investigated. The black deposited substances were inspected for the thickness of deposit, surface roughness, structural arrangement examined using Raman spectroscopy, and characteristics of electric discharge in a test bench, which was set up to simulate the ECR ion source.
authors.affiliation: Energy Systems Center, Mitsubishi Electric Corporation, 1-1-2 Wadasaki-cho, Hyogo-ku, Kobe 652-8555, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kishii
authors.affiliation: Energy Systems Center, Mitsubishi Electric Corporation, 1-1-2 Wadasaki-cho, Hyogo-ku, Kobe 652-8555, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kawasaki
authors.affiliation: National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kitagawa
authors.affiliation: National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Muramatsu
authors.affiliation: Bio-Nano Electronics Research Center, Toyo University, 2100 Kujirai, Kawagoe 350-8585, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uchida
mesh_terms: D017357:Cyclotrons; D004560:Electricity; D004566:Electrodes; D004583:Electrons; D004867:Equipment Design; D063193:Heavy Ion Radiotherapy / Q000295:instrumentation*; D009369:Neoplasms / Q000532:radiotherapy*