  The LHCb experiment is preparing for a major upgrade in 2018-2019. One of the
key components in the upgrade is a new silicon tracker situated upstream of the
analysis magnet of the experiment. The Upstream Tracker (UT) will consist of
four planes of silicon strip detectors, with each plane covering an area of
about 2 m$^2$. An important consideration of these detectors is their
performance after they have been exposed to a large radiation dose. In this
article we present test beam results of pre-prototype n-in-p and p-in-n sensors
that have been irradiated with fluences up to $4.0\times10^{14}$ $n_{\rm eq}$
cm$^{-2}$.
