  One of the major goals of the NEXT-White (NEW) detector is to demonstrate the
energy resolution that an electroluminescent high pressure xenon TPC can
achieve for high energy tracks. For this purpose, energy calibrations with
137Cs and 232Th sources have been carried out as a part of the long run taken
with the detector during most of 2017. This paper describes the initial results
obtained with those calibrations, showing excellent linearity and an energy
resolution that extrapolates to approximately 1% FWHM at Q$_{\beta\beta}$.
