@article{oai:nifs-repository.repo.nii.ac.jp:00010501,
 author = {TOKUZAWA,  Tokihiko and KISAKI,  Masashi and NAGAOKA,  Kenichi and NAGAOKA, Ken-ichi and TSUMORI,  Katsuyoshi and ITO,  Yasuhiko and IKEDA,  Katsunori and NAKANO,  Haruhisa and OSAKABE,  Masaki and TAKEIRI,  Yasuhiko and KANEKO,  Osamu},
 journal = {Review of Scientific Instruments},
 month = {Aug},
 note = {The upgraded millimeter-wave interferometer with the frequency of 70 GHz is installed on a large-scaled negative ion source. Measurable line-averaged electron density is from 2×1015to 3×1018m−3in front of the plasma grid. Several improvements such as the change to shorter wavelength probing with low noise, the installation of special ordered horn antenna, the signal modulation for a high accuracy  digital  phase  detection,  the  insertion  of  insulator,  and  so  on,  are  carried  out  for  the measurement during the beam extraction by applying high voltage. The line-averaged electron density is  successfully  measured  and  it  is  found  that  it  increases  linearly  with  the  arc  power  and  drops suddenly at the beam extraction.},
 title = {Upgraded millimeter-wave interferometer for measuring the electron density during the beam extraction in the negative ion source},
 volume = {87},
 year = {2016}
}