  For the final running period of HERA, a recoil detector was installed at the
HERMES experiment to improve measurements of hard exclusive processes in
charged-lepton nucleon scattering. Here, deeply virtual Compton scattering is
of particular interest as this process provides constraints on generalised
parton distributions that give access to the total angular momenta of quarks
within the nucleon. The HERMES recoil detector was designed to improve the
selection of exclusive events by a direct measurement of the four-momentum of
the recoiling particle. It consisted of three components: two layers of
double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel
scintillating fibre tracker, and a photon detector. All sub-detectors were
located inside a solenoidal magnetic field with an integrated field strength of
1 T. The recoil detector was installed in late 2005. After the commissioning of
all components was finished in September 2006, it operated stably until the end
of data taking at HERA end of June 2007. The present paper gives a brief
overview of the physics processes of interest and the general detector design.
The recoil detector components, their calibration, the momentum reconstruction
of charged particles, and the event selection are described in detail. The
paper closes with a summary of the performance of the detection system.
