  We present measurements of the electron-recoil (ER) response of the LUX dark
matter detector based upon 170,000 highly pure and spatially-uniform tritium
decays. We reconstruct the tritium energy spectrum using the combined energy
model and find good agreement with expectations. We report the average charge
and light yields of ER events in liquid xenon at 180 V/cm and 105 V/cm and
compare the results to the NEST model. We also measure the mean charge
recombination fraction and its fluctuations, and we investigate the location
and width of the LUX ER band. These results provide input to a re-analysis of
the LUX Run3 WIMP search.
