LENA - Low Energy Neutron detector Array

The currently developed R3B setup for FAIR at GSI is capable of carrying out different experiments with unstable and exotic beams. This includes experiments with neutrons in the ejection channel, like charge-exchange reactions (p,n), the experimental approach to (α,n) reactions, which are the main source for neutrons in stars or neutron induced fission experiments. Therefore, a new detector has been developed for low-energy neutrons stemming from those various types of reactions. LENA combines high granularity to measure the angle of the emitted neutrons to around 1° precision in the lab-frame and a good time resolution of around 1 ns to resolve the time-of-flight of the neutrons from the target to the detector for neutron energys down to 80 keV.

The detection mechanism for low-energy neutrons is the proton-recoil elastic scattering of the neutrons on the protons in the detector material. LENA is an array consisting of up to 60 single detectors subdivided into smaller arrays. Each detector is built of the scintilator material bars with a photomultiplier at each end. LENA offers a wide flexibility in the setup, allowing the final arrangement depending case-by-case on the experiment to be performed.

LENA has mainly been build at ATOMKI, Debrecen, Hungary, in collaboration with GSI Darmstadt and the Goethe University of Frankfurt.

LENA   LENA at LAND setup
"Simulations and developments of the Low Energy Neutron detector Array LENA", C. Langer et al. / Nuclear Instruments and Methods in Physics Research A 659 (2011) 411–418