Caractérisation d’un calorimètre hadronique semi-digital pour le futur collisionneur ILC

The future electron-positon linear collider ILC is an international project aiming to follow and go forward the scientific program which is actually on-going at the Large Hadron Collider (LHC). Such a leptonic collider project implies also new concepts in particle detection to ensure a better event reconstruction : this can be achieved by using particle flow techniques. I worked for the last three years on one of those projects : the SDHCAL, a semi digital hadronic calorimeter based on glass resistive plate chambers (GRPC). This 48 layer sampling calorimeter is segmented in cells of one square centimeter for a total of 50 millions channels. To ensure such a high granularity without using any active cooling, a special care has to be taken concerning the power dissipation. To decrease the embedded front end boards consumption, a multi threshold readout (semi digital) is being used instead of an analog one. Thanks to the power pulsing mechanism using the spill structure of the collider, we have recently proven the validity of this power management scenario. After two years of GRPC detector development going along with electronic readout implementation, we were able to produce one square meter detectors. I was then mainly involved in the construction of a physical prototype built as a proof of concept. This one cubic meter detector hosts more than 400 000 channels, and weight around 10 Tons. In the last few month of my thesis I was in charge of the commissioning of this prototype on CERN beam lines. The firsts pions showers recorded during this period proved that from the technical point of view the system is working as expected.