2.1. N-in-n pixel sensor
Planar pixel sensors for the IBL project were tested in different steps up to the IBL requirements. The slim edge design and the reduced number of guard rings made it possible to decrease the inactive area to . Edge efficiency studies on thick and neutron irradiated samples showed an efficiency drop very close to the pixel edge at 800 V. Samples with a thickness of are expected to show a better edge efficiency caused by the increased depletion zone at the same bias voltage.
The charge collection of a Sr-90 source scan with an IBL fluence proton irradiated sample is shown in Fig. 1. The peak of the Landau distribution at a Time-over-Threshold (ToT) of 5 ToT is equivalent to a charge of about 8.3 ke−. This exceeds the threshold of 1.6 ke− by more than 6.5 ke− and shows that the sensors can be operated at IBL fluences.