  The scheduled High Luminosity upgrade of the CERN Large Hadron Collider
presents new challenges in terms of radiation hardness. As a consequence,
campaigns to qualify the radiation hardness of detector sensors and components
are undertaken worldwide. The effects of irradiation with beams of different
particle species and energy, aiming to assess displacement damage in
semiconductor devices, are communicated in terms of the equivalent 1 MeV
neutron fluence, using the hardness factor for the conversion. In this work,
the hardness factors for protons at three different kinetic energies have been
measured by analysing the I-V and C-V characteristics of reverse biased diodes,
pre- and post-irradiation. The sensors were irradiated at the MC40 Cyclotron of
the University of Birmingham, the cyclotron at the Karlsruhe Institute of
Technology, and the IRRAD proton facility at CERN, with the respective measured
proton hardness factors being: 2.1 +/- 0.5 for 24 MeV, 2.2 +/- 0.4 for 23 MeV,
and 0.62 +/- 0.04 for 23 GeV. The hardness factors currently used in these
three facilities are in agreement with the presented measurements.
