  The NEXT-White detector, a high-pressure gaseous xenon time projection
chamber, demonstrated the excellence of this technology for future neutrinoless
double beta decay searches using photomultiplier tubes (PMTs) to measure energy
and silicon photomultipliers (SiPMs) to extract topology information. This
analysis uses $^{83m}\text{Kr}$ data from the NEXT-White detector to measure
and understand the energy resolution that can be obtained with the SiPMs,
rather than with PMTs. The energy resolution obtained of (10.9 $\pm$ 0.6) $\%$,
full-width half-maximum, is slightly larger than predicted based on the photon
statistics resulting from very low light detection coverage of the SiPM plane
in the NEXT-White detector. The difference in the predicted and measured
resolution is attributed to poor corrections, which are expected to be improved
with larger statistics. Furthermore, the noise of the SiPMs is shown to not be
a dominant factor in the energy resolution and may be negligible when noise
subtraction is applied appropriately, for high-energy events or larger SiPM
coverage detectors. These results, which are extrapolated to estimate the
response of large coverage SiPM planes, are promising for the development of
future, SiPM-only, readout planes that can offer imaging and achieve similar
energy resolution to that previously demonstrated with PMTs.
