  We describe an improved in-situ calibration of the single-photoelectron
charge distributions for each of the in-ice Hamamatsu Photonics R7081-02[MOD]
photomultiplier tubes in the IceCube Neutrino Observatory. The characterization
of the individual PMT charge distributions is important for PMT calibration,
data and Monte Carlo simulation agreement, and understanding the effect of
hardware differences within the detector. We discuss the single photoelectron
identification procedure and how we extract the single-photoelectron charge
distribution using a deconvolution of the multiple-photoelectron charge
distribution.
