Properties and Performance of SiPM based Cherenkov Telescope for LHAASO
2019 July 22
The Wide Field of View Cherenkov Telescope Array (WFCTA), one of the main component of LHAASO. It is composed by 18 imaging air Cherenkov telescopes, whose main scientific goal is to measure the ultra-high energy cosmic ray energy spectrum and composition from 30 TeV to a couple of EeV. Each Cherenkov telescope is equipped with a SiPM-based camera composed by an array of 32°×32° pixels, with angular size 0.5°×0.5°, covering a field of view 16°×16°. The SiPMs allow Cherenkov telescope to operate with the moon light thus increasing the duty cycle up to 30%, much more than the 10% achieved by PMT-based telescope. The camera pixel is a square SiPM with photosensitive area of 15 mm×15 mm and with a cell size of 25 μm×25 μm. The total active area of a WFCTA, instrumented with SiPMs, is about 4.15 m^2, representing the first large-scale application of SiPM technology in cosmic ray experiments. The first WFCTA Cherenkov telescope was successfully put in operation at the January 2019 and a second one is being set-up at the LHAASO site in May 2019. More than 220,000 coincidence events of Cherenkov telescopes and the first pool of the water Cherenkov detector array (WCDA) have been collected. The properties and first performance of the telescope are described in this work.