  The ATLAS Forward Proton (AFP) detector is intended to measure protons
scattered at small angles from the ATLAS interaction point. To this end, a
combination of 3D Silicon pixel tracking modules and Quartz-Cherenkov
time-of-flight (ToF) detectors is installed 210m away from the interaction
point at both sides of ATLAS. Beam tests with an AFP prototype detector
combining tracking and timing sub-detectors and a common readout have been
performed at the CERN-SPS test-beam facility in November 2014 and September
2015 to complete the system integration and to study the detector performance.
The successful tracking-timing integration was demonstrated. Good tracker hit
efficiencies above 99.9% at a sensor tilt of 14{\deg}, as foreseen for AFP,
were observed. Spatial resolutions in the short pixel direction with 50 {\mu}m
pitch of 5.5 +/- 0.5 {\mu}m per pixel plane and of 2.8 +/- 0.5 {\mu}m for the
full four-plane tracker at 14{\deg} were found, largely surpassing the AFP
requirement of 10 {\mu}m. The timing detector showed also good hit efficiencies
above 99%, and a full-system time resolution of 35 +/- 6 ps was found for the
ToF prototype detector with two Quartz bars in-line (half the final AFP size)
without dedicated optimisation, fulfilling the requirements for initial
low-luminosity AFP runs.
