Scintillator counters with WLS fiber/MPPC readout for the side muon range detector (SMRD) of the T2K experiment

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2010-11, Vol.623 (1), p.382-384
• Main Authors: Izmaylov, A., Aoki, S., Blocki, J., Brinson, J., Dabrowska, A., Danko, I., Dziewiecki, M., Ellison, B., Golyshkin, L., Gould, R., Hara, T., Hartfiel, B., Holeczek, J., Khabibullin, M., Khotjantsev, A., Kielczewska, D., Kisiel, J., Kozlowski, T., Kudenko, Yu, Kurjata, R., Kutter, T., Lagoda, J., Liu, J., Marzec, J., Metcalf, W., Mijakowski, P., Mineev, O., Musienko, Yu, Naples, D., Nauman, M., Northacker, D., Nowak, J., Paolone, V., Posiadala, M., Przewlocki, P., Reid, J., Rondio, E., Shaykhiev, A., Sienkiewicz, M., Smith, D., Sobczyk, J., Stodulski, M., Straczek, A., Sulej, R., Suzuki, A., Swierblewski, J., Szeglowski, T., Szeptycka, M., Wachala, T., Warner, D., Yershov, N., Yano, T., Zalewska, A., Zaremba, K., Ziembicki, M.
• Format: Article
• Language: English
• Subjects: Neutrino detectors; Scintillator counters; Wavelength-shifting fibers
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2010.03.009

The T2K neutrino experiment at J-PARC uses a set of near detectors to measure the properties of an unoscillated neutrino beam and neutrino interaction cross-sections. One of the sub-detectors of the near-detector complex, the side muon range detector (SMRD), is described in the paper. The detector is designed to help measure the neutrino energy spectrum, to identify background and to calibrate the other detectors. The active elements of the SMRD consist of 0.7cm thick extruded scintillator slabs inserted into air gaps of the UA1 magnet yokes. The readout of each scintillator slab is provided through a single WLS fiber embedded into a serpentine-shaped groove. Two Hamamatsu multi–pixel avalanche photodiodes (MPPC's) are coupled to both ends of the WLS fiber. This design allows us to achieve a high MIP detection efficiency of greater than 99%. A light yield of 25–50p.e./MIP, a time resolution of about 1ns and a spatial resolution along the slab better than 10cm were obtained for the SMRD counters.