A new plasma‐surface interactions research facility: PISCES‐B and first materials erosion experiments on bulk‐boronized graphite

Abstract

A new plasma‐surface interactions research facility, PISCES‐B, has been designed and constructed at the University of California, Los Angeles (UCLA). The entire vacuum chamber is bakable and a base pressure of the order of 10−8 Torr is attainable. The PISCES‐B facility can generate continuous plasmas of argon, helium, hydrogen, deuterium, and nitrogen. The density of these plasmas ranges from 1×1011 to 3×1013 cm−3 and the electron temperature ranges from 3 to 51 eV. The plasma bombarding flux to the target can be varied from 1×1017 to 8×1018 ions cm−2 s−1. The neutral pressure is controllable in the range from 3×10−5 to 1×10−3 Torr during plasma operation. An in situ surface analysis station with Auger electron spectroscopy (AES), x‐ray photoemission spectroscopy (XPS), and secondary ion mass spectroscopy capabilities is attached to the main plasma experimental chamber. Using the PISCES‐B facility, first materials erosion experiments have been conducted on newly developed bulk‐boronized graphites and selected isotropic graphites for comparison. The erosion yield for 3% boronized graphite due to hydrogen plasma bombardment has been found to be reduced by 30%–40%, relative to isotropic graphites, both in the chemical sputtering and radiation enhanced sublimation regimes at temperatures from 100 to 1300 °C. No significant surface composition change is observed for boronized graphite after plasma bombardment to a total fluence of the order of 1022 ions cm−2.