Electrostatic energy analyzer measurements of low energy zirconium beam parameters in a plasma sputter-type negative ion source

Abstract

A plasma sputter-type negative ion source is utilized to produce and detect negative Zr ions with energies between 150 and 450 eV via a retarding potential-type electrostatic energy analyzer. Traditional and modified semi-cylindrical Faraday cups (FC) inside the analyzer are employed to sample negative Zr ions and measure corresponding ion currents. The traditional FC registered indistinct ion current readings which are attributed to backscattering of ions and secondary electron emissions. The modified Faraday cup with biased repeller guard ring, cut out these signal distortions leaving only ringings as issues which are theoretically compensated by fitting a sigmoidal function into the data. The mean energy and energy spread are calculated using the ion current versus retarding potential data while the beam width values are determined from the data of the transverse measurement of ion current. The most energetic negative Zr ions yield tighter energy spread at 4.11 eV compared to the least energetic negative Zr ions at 4.79 eV. The smallest calculated beam width is 1.04 cm for the negative Zr ions with the highest mean energy indicating a more focused beam in contrast to the less energetic negative Zr ions due to space charge forces.

Effects Of Negative Ag Ions On The Surface Of (200) Single-Crystalline MgO Substrates

“…Beam profiling is needed in order to determine as to whether or not the bombarding ions belong to silver. This was conducted under vacuum conditions using the plasma sputter type negative ion source described in reference [12]. It is a one-liter volume, single filament ion source surrounded by Sm-Co magnets to form a multi-cusp field for plasma confinement.…”