Characterization of New Large Scintillator Bars for the Low Energy Neutron Detector Array LENDA

Abstract

The Low Energy Neutron Detector Array (LENDA) in the National Super- conducting Cyclotron Laboratory at Michigan State University is a time-of-flight spectrometer that was designed with the intention of studying charge-exchange (p; n) reactions using plastic scintillating bars. The NSCL has begun to research reactions that require the study of higher energy neutrons that LENDA is unable to efficiently detect in its current form. These higher energy (a; n) reactions of interest have strong astrophysical motivations due to their importance in the synthesis of heavy elements and neutron capture reactions. The solution for upgrading LENDA is to use larger scintillating bars whose increased dimensions make them more suitable for the detection of higher energy ranges. The larger bars used by the LENDA team are referred to as Kolata bars for their use in Jim Kolata's Neutron Wall Experiment at the University of Notre Dame in 2006. Additionally, the only difference between the original LENDA bars and these larger Kolata bars is the dimensions, meaning that all connections, wires, and software are compatible between the entire LENDA system and the new bars. Before the bars can be used, their characteristics and conditions must each be individually assessed and documented. In this paper, the author presents the method that the team created to characterize each new Kolata bar, ensuring that they can be reliably used for future nuclear physics research at the NSCL.