Very high energy gamma-ray astronomy is a relatively young part of astronomy (30 years), looking at the sky above 50 GeV. After the success of the H.E.S.S. array in the 2000s, an international observatory, the Cherenkov Telescope Array (CTA), should start operating by 2025. This observatory will include a total of 50 telescopes, distributed on two sites. IRFU is involved in the construction of the NectarCAM, a camera intended to equip the 'medium' telescopes (MST) of CTA. The first NectarCAM (of the nine planned) is being integrated at IRFU and will be installed on the North site of CTA in 2025. Once the camera is installed, the first astronomical observations will take place, allowing to fully validate the functioning of the camera. The thesis aims at finalizing the darkroom tests at IRFU, preparing the installation and validating the operation of the camera on the CTA site with the first astronomical observations. It is also planned for the student to participate in H.E.S.S. data analysis on astroparticle topics (search for primordial black holes, constraints on Lorentz Invariance using distant AGN).