Speaker
Description
A promising approach for the future ATLAS pixel detector at the HL-LHC is the usage of 3D-silicon sensors for the inner layers and the utilization of commercial CMOS technologies for the sensors of the outer layers.
3D-silicon sensors (FBK, CNM) and planar 200/250 um thick n-in-n sensors (CiS) as used for ATLAS IBL, along with passive CMOS pixel sensors in 150 nm technology (LFoundry) were characterized using the ATLAS FE-I4. Precise charge-collection efficiency (CCE) studies were carried out with $^{90}$Sr at bias voltages between 20 – 1500 V after irradiation with 24 MeV protons up to $7\cdot10^{15}\ \mathrm{N_{eq}/cm^2}$. A GEANT4 based simulation was conducted to understand the complications arising from single pixel charge measurements with low energetic beta sources. The measured charge spectra before irradiation are compared to the GEANT4 simulation. For the description of the charge collection efficiency after irradiation a new Python based software (SCARCE) was programmed that calculates drift- and weighting fields for pixel matrices with planar and 3D electrode configurations. Despite simple assumptions (homogeneous $\mathrm{N_{eff}}$, $\tau_{e}=\tau_{h}$, 2D simulation) the measured CCE(Vbias) curves were successfully reproduced at a fluence of $1\cdot10^{15}\ \mathrm{N_{eq}/cm^2}$. For the novel passive CMOS sensors key properties like breakdown behavior, depletion depth, and particle detection efficiency will be shown.
