  The resistivity of polycrystalline chemical vapor deposition diamond sensors
is studied in samples exposed to fluences relevant to the environment of the
High Luminosity Large Hadron Collider. We measure the leakage current for a
range of bias voltages on samples irradiated with 800 MeV protons up to
1.6\times 10^{16} p/cm^2. The proton beam at LANSCE, Los Alamos National
Laboratory, was applied to irradiate the samples. The devices' resistivity is
extracted for temperatures in the -10^\circC to +20^\circC range.
