Detection of fast neutrons for R3B and EXL at FAIR

The R3B and EXL projects at the FAIR facility aim for investigation of unstable nuclei by means of reactions with high-energy radioactive beams in inverse kinematics. A high resolution neutron time-of-flight spectrometer NeuLAND is currently being developed for the study of reactions involving emission of projectile-like neutrons. With the design goals of σt ∼ 100 ps and σx,y,z ∼ 1 cm, a resolution for the excitation energy of up to ΔE ∼ 30 keV at the neutron threshold can be reached. The neutrons are detected via their interaction in a converter, producing dominantly protons at various energies. While the existing neutron detector LAND is built from a converter-scintillator structure, for NeuLAND the use of resistive plate chambers (RPC) is planned. Since up to now RPCs were mainly developed for detection of minimum ionizing particles, the response of RPCs to protons (30 to 190 MeV) has been investigated in a test experiment performed at KVI with two RPC prototypes from the FOPI and HADES collaborations. (orig.)