The surface detector array of the Telescope Array experiment
  The Telescope Array (TA) experiment, located in the western desert of Utah,USA, is designed for observation of extensive air showers from extremely high energy cosmic rays. The experiment has a surface detector array surrounded by three fluorescence detectors to enable simultaneous detection of shower particles at ground level and fluorescence photons along the shower track. The TA surface detectors and fluorescence detectors started full hybrid observation in March, 2008. In this article we describe the design and technical features of the TA surface detector. 
T. Abu-Zayyad, R. Aida, M. Allen, R. Anderson, R. Azuma, E.   Barcikowski, J. W. Belz, D. R. Bergman, S. A. Blake, R. Cady, ...
astro-ph.IM