  The upgrades of ATLAS and CMS for the High Luminosity LHC (HL-LHC)
highlighted physics objects timing as a tool to resolve primary interactions
within a bunch crossing. Since the expected pile-up is around 200, with an
r.m.s. time spread of 180 ps, a time resolution of about 30 ps is needed. The
timing detectors will experience a 1-MeV neutron equivalent fluence of about
$\Phi_{eq}=10^{14}$ and $10^{15}$ cm$^{-2}$ for the barrel and end-cap regions,
respectively. In this contribution, deep diffused Avalanche Photo Diodes (APDs)
produced by Radiation Monitoring Devices are examined as candidate timing
detectors for HL-LHC applications. To improve the detector's timing
performance, the APDs are used to directly detect the traversing particles,
without a radiator medium where light is produced. Devices with an active area
of $8\times8$ mm$^2$ were characterized in beam tests. The timing performance
and signal properties were measured as a function of position on the detector
using a beam telescope and a microchannel plate photomultiplier (MCP-PMT).
Devices with an active area of $2\times2$ mm$^2$ were used to determine the
effects of radiation damage and characterized using a ps pulsed laser. These
detectors were irradiated with neutrons up to $\Phi_{eq}=10^{15}$ cm$^{-2}$.
