title: Fine-tuning to minimize emittances of J-PARC RF-driven H⁻ ion source.
abstract: The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H(-) ion source has been successfully operated for about one year. By the world's brightest level beam, the J-PARC design beam power of 1 MW was successfully demonstrated. In order to minimize the transverse emittances, the rod-filter-field (RFF) was optimized by changing the triple-gap-lengths of each of pairing five piece rod-filter-magnets. The larger emittance degradation seems to be caused by impurity-gases than the RFF. The smaller beam-hole-diameter of the extraction electrode caused the more than expected improvements on not only the emittances but also the peak beam intensity.
authors.affiliation: J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Ueno
authors.affiliation: J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohkoshi
authors.affiliation: J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ikegami
authors.affiliation: J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Takagi
authors.affiliation: J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Asano
authors.affiliation: J-PARC Center, Tokai-Mura, Naka-Gun, Ibaraki-Ken 319-1195, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Oguri