NOvA is a two detector, long baseline neutrino oscillation experiment designed to study nue (nue bar) appearance and numu (numu bar) disappearance in a numu (numu bar) beam produced at Fermilab. The near detector
(ND) is located 100 meters underground at a distance of 1 km from the target whereas the far
detector (FD) is located on the surface, 810 km away from the target in Ash River, MN. Both
detectors are functionally identical and consist of alternating planes of horizontal and vertical
plastic extruded cells filled with liquid scintillator. Each cell has a looped wavelength shifting
(WLS) fiber coupled to one pixel of an Avalanche Photodiode (APD). The WLS fiber is used to
transport the light produced by a charged particle traversing the scintillator to the APD. The light
is attenuated while traveling through the fiber and these losses are corrected by using cosmic ray
muons to calibrate the NOvA detectors. This poster elaborates the detailed methodology used in
the attenuation calibration of the NOvA detectors.
