Analysis of a Traditional Field-Shaping Structure for the ND-LAr Detector

The Deep Underground Neutrino Experiment (DUNE) Liquid Argon Near Detector (ND-LAr) will be composed of 35 time projection chamber (TPC) modules for its measurements. The electric field that will drift ionization electrons in these TPC modules is created by a field-shaping structure. Studies of a traditional field-shaping structure design that steps down the high voltage by employing resistors across many copper strips will be presented in this talk. The use of a discrete pattern of strips leads to non-uniformities in the electric field that can distort the paths of drifting electrons. We sought to compare the field non-uniformities between multiple strip geometries in order to understand what minimized them, and how they affected the drift path of electrons. Our results concluded that the most uniform electric field and least drift distortions were produced by strip geometries with smaller strip widths and strip spacings. These findings should be considered in the design of a traditional field-shaping structure for the ND-LAr detector.