33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE The Selection of PMT for LHAASO-WFCTA and the PMT Testing Facility

Abstract: The performance of Wide Field Cherenkov Telescope Array(WFCTA) are highly sensitive to linear dynamic range, gain, dark noise and uniformity of cathode sensitivity of photomultiplier tube(PMT). These characteristics of each PMT in WFCTA need to be tested and linear dynamic range of PMT need to be extended by employ new method. For this purpose, a system has been built, and the above characteristics of several types of PMT have been tested in different signal read-out methods and different voltage dividers. According to the test results, ET 9078B, Hamamatsu R1924A, R4125, and Beijing Hamamatsu CR303 (with a flat cathode) meets the requirement of WFCTA. Linear dynamic range of these PMT is extended by use a specific tapered voltage divider and read-out signal from the 10th dynode