12-20 July 2017
BEXCO
Asia/Seoul timezone
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Contribution

BEXCO - Room F(201/202/203/204)

[GA088] The time calibration system for the LHAASO-WCDA experiment

Speakers

  • Bo GAO

Primary authors

  • Bo GAO (Insititute of High Energy Physic Chinese Academy of Science)

Co-authors

  • Jinyan LIU (University of Nankai)
  • Huicai LI (Insititute of High Energy Physic Chinese Academy of Sciences)
  • Min ZHA (Insititute of High Energy Physic Chinese Academy of Sciences)
  • Hanrong WU (Insititute of High Energy Physic Chinese Academy of Sciences)
  • Mingjun CHEN (Insititute of High Energy Physic Chinese Academy of Sciences)
  • Zhiguo YAO (Insititute of High Energy Physic Chinese Academy of Sciences)

Description

The Water Cherenkov Detector Array (WCDA), which is one of the main components of the Large High Altitude Air Shower Observatory (LHAASO), functions as surveying the northern sky for high-energy gamma ray sources at the energy range around 100 GeV--30 TeV. The precision of the time measurement for shower particles hitting every detector in the array directly associates the detection sensitivity for the sources. In order to make the pointing error of the detector to any point source less than 0.1°, the calibration precision of the time offsets among detector cells should be less than 0.2 ns. To reach this goal, a method called "cross calibration" is to be employed for the detector array, with 180 bundles of fiber systems guiding the lights of LEDs to each PMT. A prototype of the time calibration system is developed, which is based on a fast LED, a plastic fiber bundle and an FPGA control board. The prototype is tested in the lab and the error propagation based on the measured parameters shows that it fulfills the requirement.