Title: The aCORN Backscatter-Suppressed Beta Spectrometer,
Abstract: Backscatter of electrons from a beta spectrometer, with incomplete energy
deposition, can lead to undesirable effects in many types of experiments. We
present and discuss the design and operation of a backscatter-suppressed beta
spectrometer that was developed as part of a program to measure the
electron-antineutrino correlation coefficient in neutron beta decay (aCORN). An
array of backscatter veto detectors surrounds a plastic scintillator beta
energy detector. The spectrometer contains an axial magnetic field gradient, so
electrons are efficiently admitted but have a low probability for escaping back
through the entrance after backscattering. The design, construction,
calibration, and performance of the spectrometer are discussed.