Vertical test of a half-wave resonator at the rare isotope science project

A vertical test of the β = 0.12 half-wave resonator prototype at the Rare Isotope Science Project (RISP) was done at TRIUMF, Canada. The design goal of Q₀ = 1.9 × 10⁹ at an accelerating gradient of E_acc = 6.3 MV/m at 2 K was achieved. Moreover, the residual resistance, the sensitivity against helium pressure fluctuations, and the Lorentz force detuning were also measured. The performance was limited by field emission at around E_acc = 8.1 MV/m. In addition to the vertical test result, the surface processing is described in this paper.