LENDA, a Low Energy Neutron Detector Array for experiments with radioactive beams in inverse kinematics

TL;DR

LENDA is a specialized neutron detector array designed for inverse kinematics experiments with radioactive beams, capable of high-efficiency detection of low-energy neutrons for nuclear physics research.

Contribution

The paper introduces LENDA, a novel low-energy neutron detector array optimized for inverse kinematics experiments with rare isotope beams, including its design, characterization, and performance.

Findings

Neutron energy threshold below 150 keV achieved.

Intrinsic time resolution around 400 ps demonstrated.

Detection efficiency exceeds 20% for neutrons below 4 MeV.

Abstract

The Low Energy Neutron Detector Array (LENDA) is a neutron time-of-flight (TOF) spectrometer developed at the National Superconducting Cyclotron Lab- oratory (NSCL) for use in inverse kinematics experiments with rare isotope beams. Its design has been motivated by the need to study the spin-isospin response of unstable nuclei using (p, n) charge-exchange reactions at intermediate energies (> 100 MeV/u). It can be used, however, for any reaction study that involves emission of low energy neutrons (150 keV - 10 MeV). The array consists of 24 plastic scintillator bars and is capable of registering the recoiling neutron energy and angle with high detection efficiency. The neutron energy is determined by the time-of-flight technique, while the position of interaction is deduced using the timing and energy information from the two photomultipliers of each bar. A simple test setup utilizing radioactive sources has been used to characterize the array. Results of test measurements are compared with simulations. A neutron energy threshold of < 150 keV, an intrinsic time (position) resolution of \sim 400 ps (\sim 6 cm) and an efficiency > 20 % for neutrons below 4 MeV have been obtained.