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

The study of /spl nu//sub /spl mu// to /spl nu//sub 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 /spl sim/ 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.