A segmented neutron detector has been constructed and used for recoil neutr
on (6-13 MeV) measurements of the reaction gamma p --> n pi(+) very close t
o threshold. BC-505 liquid scintillator was used to allow pulse shape discr
imination between neutrons and photons. A measurement of the absolute effic
iency of the detector was performed using stopped pions in the reaction pi(
-)p --> n gamma. Results of the efficiency calibration are compared to a Mo
nte Carlo simulation. (C) 1999 Elsevier Science B.V. All rights reserved.