A scanning apparatus having a mechanism for adjusting an opening of a sheet passageway includes a first assembly, a second assembly and a driving mechanism. The advantages may include increased spring constant, increased variability control, and increased packaging efficiency. An excitation spectrum of the first phosphor includes, at excitation wavelengths longer than 530 nm, no intensities greater than about 60% of a maximum intensity of the excitation spectrum. At running time, the system and method uses an approximate from-point visibility algorithm to dynamically determine which parts of the model to retrieve from disk. The control means uses programmable logic to cause the optical network unit to function within established protocols.