Testing and constructing BAND, a backward angle neutron detector for CLAS12.*

The Backward Angle Neutron Detector (BAND) is a scintillator array planned to be part of the CLAS12 detector at Jefferson Lab. BAND is specifically designed to detect recoiling spectator neutrons in deep inelastic scattering collisions between the accelerated electron beam and protons in deuterium nuclei, with the goal of understanding the structure functions of these bound protons. Scattering events with fast-moving neutrons emitted at large angles relative to the momentum transfer imply the deuteron was in a short-range correlated (SRC) configuration before the collision. BAND will be positioned upstream of the CLAS12 target and will cover scattering angles from 160° to 170°. Time-of-flight will be used to determine neutron momenta within an uncertainty of 1.5%, given BAND’s expected 300ps time resolution. This will clarify the relationship between modification of the structure function and nucleon virtuality, and could impact present understanding of the EMC effect and its relation to nucleons in SRC configurations. I will present the methods used to test BAND’s components and complete its assembly.