  The silicon drift detectors are at the basis of the instrumentation aboard
the Large Observatory For x-ray Timing (LOFT) satellite mission, which
underwent a three year assessment phase within the "Cosmic Vision 2015 - 2025"
long-term science plan of the European Space Agency. Silicon detectors are
especially sensitive to the displacement damage, produced by the non ionising
energy losses of charged and neutral particles, leading to an increase of the
device leakage current and thus worsening the spectral resolution.
  During the LOFT assessment phase, we irradiated two silicon drift detectors
with a proton beam at the Proton Irradiation Facility in the accelerator of the
Paul Scherrer Institute and we measured the increase in leakage current. In
this paper we report the results of the irradiation and we discuss the impact
of the radiation damage on the LOFT scientific performance.

Instrumentation and Methods for Astrophysics;High Energy Astrophysical Phenomena;Instrumentation and Detectors