Abstract
The Wide Field-of-View Cherenkov Telescope Array (WFCTA) and the Water Cherenkov Detector Array (WCDA) of LHAASO are designed to work in combination for measuring the energy spectra of the cosmic ray species over a very wide energy range from a few TeV to 10 PeV. The energy calibration can be achieved with a proven technique of measuring the westward shift of the Moon shadow cast by galactic cosmic rays due to the geomagnetic field. This deflection angle Δ is inversely proportional to the cosmic ray rigidity. The precise measurement of the shifts by WCDA allows us to calibrate its energy scale for energies as high as 35 TeV. Through a set of commonly triggered events, the energy scales can be propagated to WFCTA. The energies of the events can be derived both by WCDA-1 and WFCTA with the median energies 23.4±0.1±1.3 TeV and (21.9±0.1 TeV), respectively, which are consistent within uncertainties. In addition, the propagation of the energy scale is also validated by the Moon shadow based on the same data selection criteria of the commonly triggered events. This paper reports, for the first time, an observational measurement of the absolute energy scale of the primary cosmic rays generating showers observed by air Cherenkov telescopes.
Recommended Citation
"Calibration Of The Air Shower Energy Scale Of The Water And Air Cherenkov Techniques In The LHAASO Experiment," Physical Review D, vol. 104, no. 6, article no. 062007, American Physical Society, Sep 2021.
The definitive version is available at https://doi.org/10.1103/PhysRevD.104.062007
Department(s)
Physics
International Standard Serial Number (ISSN)
2470-0029; 2470-0010
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 American Physical Society, All rights reserved.
Publication Date
15 Sep 2021
Comments
National Natural Science Foundation of China, Grant 20SYSX0294