GEANT4 photon readout simulations of plastic scintillating strips with embedded WLS fibers

The study of ν_μ to ν_e oscillations using high intensity neutrino "super beams" is the most promising avenue for measuring neutrino oscillation parameters to an order of magnitude improvement in precision. The international J-PARC/SK proto-collaboration proposes to measure these parameters with the existing SuperKamiokande (SK) detector as the far detector and a high-rate, fine-grained detector of ∼ 200 tonnes, placed near the production target to provide measurements of the initial neutrino beam flux. The near detector is based on extruded plastic scintillator strips built into 5 m by 5 m layers and read out by wavelength shifter fibers (WLS) and photomultiplier tubes (PMT\´s). An R&D program in Canada aims to optimize this mature technology for the J-PARC/SK experiment and find improvements to the photon readout system. To guide this development and to further validate the optical photon functionality in GEANT4, we added \´wavelength shifting\´ to the catalog of processes available with the toolkit, and compared simulations with controlled test bench measurements. This paper gives a short explanation of the optical photon process implementations available in GEANT4 and reports the results of our specific comparison.