An alternative energy calibration method for Timepix3

The purpose of this project is to perform an energy calibration method on the Timepix3 detector based on test pulse and source data. The Timepix3 acquisition mode allows the counter to work as a timer and measure the time of arrival (ToA) and time over threshold (ToT) for every incoming particle in a pixel in a data driven readout. As this implies a high volume of data, processing algorithms such as clustering and charge collection efficiency studies have to be taken into account. The energy measurements can be extracted from the ToT data, and converted to energy by performing a mixed calibration using test pulse data and $\gamma$ sources. Test pulse calibration shows an offset with respect to the source calibration, which is explained and corrected in order to be able to fuse them together, as source calibration values cannot be obtained properly at low energies due to experimental limitations. Compared with the factory calibration performed by Advacam, the source-test-pulse (STP) calibration shows higher accuracy for low energies when tested on Ca XRF measurements and slightly lower accuracy for higher energies, tested on Ag, Sn and Gd XRF measurements. The drift is due to temperature changes in the setup, meaning that a more stable setup could potentially increase the method's accuracy for energy measurements.