The P4DI hybrid characterization results and application in the localization of radioactive spots

The P4DI CMOS and hybrid pixel detector has 1250 pixels with 400um pitch. Pixels give simultaneously the collected charge and the time of occurrence of the hit. With different combinations of gain and peaking time it can measure signal up to 218000 electrons. A detecting plane consisting of 8 hybrids with 10000 pixels using two different bump bonding processes and Al/CdTe/Pt Schottky diodes 0.75mm and 1mm thick has been assembled. Energy resolution from the cumulative spectrum from all pixels is: 2.9KeV FWHM at 59.54 KeV, 3 KeV FWHM at 122 KeV and 5.74 KeV FWHM at 356 KeV at 23°C. Timing resolution is 7μs FWHM. The detecting plane is used in experiments for the localization of radioactive sources with the aid of coded apertures. Angular resolution of 4.6° within a Fully Coded Field of View of 75°× 75° has been demonstrated.