Investigating linearity and producing monitoring plots with the calibration systems of the ATLAS Tile Calorimeter

In this project, I used two calibration methods of the Tile Calorimeter detector of ATLAS to achieve two goals: describe the linearity of different photomultipliers (PMTs) with the laser calibration system, and create monitoring plots for the charge injection calibration system. First, the different kind of PMTs present in the detector were separated into 3 groups: the legacy and a new model of PMTs connected to legacy electronics, and the new PMTs connected to new electronics (a prototype of the electronics that will be installed during the High Luminosity Large Hadron Collider (HL-LHC) upgrade). Using different quantities to describe the PMT response's deviation from linearity, it was observed that the HL-LHC demonstrator,  a hybrid module equipped with prototypes of the HL-LHC electronics but with backward compatibility with the legacy system, showed more nonlinearity than the other observed PMTs. In the second part of the project, a toolkit was developed to make long-term monitoring plots of the calibration constant obtained from charge injection measurements. It creates a simple way to see the difference  between the measured calibration constants and the ones stored in the Tile Calorimeter database for all approx. 10000 channels. A webpage to display all of these plots was also prepared to ensure easy access to the monitoring tools.