| The angular response of the photomultiplier tubes (PMTs) of the Sudbury Neutrino Observatory (SNO) is measured for an extended detector volume. Analytic and Monte Carlo studies of the reflections on the acrylic vessel made possible a full analysis of the optical data taken in a fiducial volume of 550 cm in radius, a 25% increase compared to previous analysis methods.; The heavy and light water total extinctions found in that extended volume are consistent with previous measurements. The PMT angular response is also consistent, but extends in the range of incident angle [40°, 45°]. An approximation of the error due to this new optics on the energy scale uncertainty leads to a reduction of 1.25% on that uncertainty. |
