The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - CONF AU - Magome, T. AU - Hanaki, H. AU - Kobayashi, T. AU - Suzuki, S. AU - Taniuchi, T. ED - Yamazaki, Yoshishige ED - Facco, Alberto ED - McCausey, Amy ED - Schaa, Volker RW TI - Identification of Emitting Sources of Dark Currents From Gridded Thermionic Electron Gun and Measures to Suppress Dark Currents From Electron Gun in SPring-8 Linear Accelerator J2 - Proc. of LINAC2016, East Lansing, MI, USA, 25-30 September 2016 C1 - East Lansing, MI, USA T2 - Linear Accelerator Conference T3 - 28 LA - english AB - The dark current is emitted from a gridded thermionic electron gun although the grid-electrode potential against the cathode is negative enough to suppress the cathode emission current. This dark current in the SPring-8 linear accelerator caused satellite bunches unignorable for precise experiments in the downstream electron storage ring. The dark current has been investigated by means of our electron-gun test equipment applying a DC accelerator voltage to the electron gun. The investigations revealed that the dark current was generated from the wehnelt electrode, the gird electrode, and the cathode surface. The dark current from the wehnelt electrode was decreased under the measurement limit 2·10⁻¹⁵ A by replacing the wehnelt and the anode electrodes with new electro-polished ones. The dark current from the cathode surface was reduced by lowering the grid-electrode potential against the cathode down to -160 V. To reduce the dark current from the grid electrode, the surface of the grid electrode was significantly smoothed by electro-polishing. PB - JACoW CP - Geneva, Switzerland SP - 888 EP - 890 KW - cathode KW - electron KW - gun KW - acceleration KW - synchrotron DA - 2017/05 PY - 2017 SN - 978-3-95450-169-4 DO - 10.18429/JACoW-LINAC2016-THPLR021 UR - http://jacow.org/linac2016/papers/thplr021.pdf ER -