The T2K ND280 Off-Axis Pi-Zero Detector
  The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino experiment. The primary goal for the P{\O}D is to measure the relevant cross sections for neutrino interactions that generate pi-zero's, especially the cross section for neutral current pi-zero interactions, which are one of the dominant sources of background to the electron neutrino appearance signal in T2K. The P{\O}D is composed of layers of plastic scintillator alternating with water bags and brass sheets or lead sheets and is one of the first detectors to use Multi-Pixel Photon Counters (MPPCs) on a large scale. 
S. Assylbekov, B. E. Berger, H. Berns, D. Beznosko, A. Bodek, R.   Bradford, N. Buchanan, H. Budd, Y. Caffari, K. Connolly, ...
physics.ins-det hep-ex