SRF cavity and HOM damper tests at TRIUMF for ARIEL

The eLINAC for ARIEL\footnote{Advanced Rare Isotope Experiment Laboratory} consists of 5 superconducting nine cell cavities operating at 1.3 GHz, each cavity with a accelerating voltage of 10 MV. The design requires a quality factor of $1 \cdot 10^{10}$ or higher at the operating temperature of 2 K for 10 W dissipated power in the cavity walls. Latest SRF\footnote{Superconducting Radio Frequency} tests of a 1.3 GHz niobium single cell cavity will show that procedures at TRIUMF are capable of exceeding the RF requirements of ARIEL. Future upgrade plans for the eLINAC include a recirculating arc to either increase the energy of the 10 mA electron beam or drive an FEL\footnote{Free Electron Laser} in ERL\footnote{Energy Recovery LINAC} mode. BBU\footnote{Beam Break-Up} is a limitation in recirculating LINACs. Its strength depends on a number of parameters including the shunt impedance $R_{Sh}$ of HOM,\footnote{Higher Order Modes} especially dipole modes, of the SRF cavity. Using beam line absorbers made out of a low electric conductive material reduces the $Q_L$ of the cavity and therefore reduces the $R_{Sh}$. Qualification of such a material is essential and measurements of the electrical conductivity of a candidate material will be presented in addition to the cavity tests.