[Title] Accurate Reflectance Measurement of Spherical Mirror at Multi-wavelength on LHAASO-WFCTA

• Teaching and Research Group:天体物理
• Journal:Proceedings of Science
• Key Words:Cherenkov telescope;WFCTA;spherical mirror;reflectance;multi-wavelength measurement
• Abstract:The Wide Field of View Cherenkov Telescope Array (WFCTA) is an important component of the Large High Altitude Air Shower Observatory (LHAASO). Each Cherenkov telescope is equipped with a large-aperture spherical mirror composed of multiple sub-mirrors,whose reflectance directly affects the measurement of Cherenkov light and thus the reconstruction of cosmic-ray energy. This paper presents a dedicated reflectance measurement system designed for spherical mirrors,employing semiconductor lasers at five wavelengths (405,450,488,520,and 650 nm) and an integrating sphere coupled with a photomultiplier tube. System stability and systematic errors are carefully evaluated in laboratory tests. On-site measurements are then carried out on all 18 WFCTA telescopes,with 175 measurement points covering each spherical mirror. The average reflectance values at different wavelengths are obtained,providing a reliable experimental basis for long-term calibration and performance evaluation of the LHAASO-WFCTA telescopes.
• Co-author:Wang YD,Zhu FR,Zhang SS,Wang Y,Chen L,Liu Y
• First Author:Jin M
• Document Code:029
• Discipline:Science
• First-Level Discipline:Astronomy
• Volume:444(HEASA2023)
• Page Number:id.502
• Translation or Not:no
• Date of Publication:2024-09-01