  The Cherenkov Telescope Array (CTA) represents the next generation of very
high-energy gamma-ray observatory, which will provide broad coverage of gamma
rays from 20 GeV to 300 TeV with unprecedented sensitivity. CTA will employ
three different sizes of telescopes, and the Large-Sized Telescopes (LSTs) of
23-m diameter dish will provide the sensitivity in the lowest energies down to
20 GeV. The first LST prototype has been inaugurated in October 2018 at La
Palma (Canary Islands, Spain) and has entered the commissioning phase. The
camera of the LST consists of 265 PMT modules. Each module is equipped with
seven high-quantum-efficiency Photomultiplier Tubes (PMTs), a slow control
board, and a readout board. Ensuring high uniformity and precise
characterization of the camera is the key aspects leading to the best
performance and low systematic uncertainty of the LST cameras. Therefore, prior
to the installation on site, we performed a quality check of all PMT modules.
Moreover, the absolute calibration of light throughput is essential to
reconstruct the amount of light received by the telescope. The amount of light
is affected by the atmosphere, by the telescope optical system and camera, and
can be calibrated using the ring-shaped images produced by cosmic-ray muons. In
this contribution, we will show the results of off-site quality control of PMT
modules and on-site calibration using muon rings. We will also highlight the
status of the development of Silicon Photomultiplier modules that could be
considered as a replacement of PMT modules for further improvement of the
camera.
