title: Low fragment polyatomic molecular ion source by using permanent magnets.
abstract: Electron-ionization-type polyatomic molecular ion source with low fragment was developed by using a pair of ring-shaped Sm-Co magnets. The magnets were placed forward and backward side of ionization part to confine electrons extracted from a thermionic cathode. Calculated electron trajectory of the developed ion source was 20 times longer than that of an ordinary outer filament configuration that has no magnetic confinement. Mass spectra of the molecular ions generated from n-tetradecane (C14H30) gas exhibited 4 times larger intensity than that of the ordinary configuration in a range of mass/charge from 93 to 210 u. This indicates that suppression of fragment ion was obtained by increase of low energy electrons resulted from the electron confinement.
authors.affiliation: Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Takeuchi
authors.affiliation: Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Kyouhei
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Imanaka
authors.affiliation: Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Ryuto
authors.affiliation: Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Gikan H
authors.initials: GH
authors.lastname: Takaoka