D. Vazquez Furelos

3D silicon pixel detectors for the High-Luminosity LHC

3D silicon pixel detectors have been investigated as radiation-hard candidates for the innermost layers of the HL-LHC upgrade of the ATLAS pixel detector. 3D detectors are already in use today in the ATLAS IBL and AFP experiments. These are based on 50 × 250 μm2 large pixels connected to the FE-I4 readout chip. Detectors of this generation were irradiated to HL-LHC fluences and demonstrated excellent radiation hardness with operational voltages as low as 180 V and power dissipation of 12–15 mW/cm2 at a fluence of about 1016 neq/cm2, measured at -25°C. Moreover, to cope with the higher occupancies expected at the HL-LHC, a first run of a new generation of 3D detectors designed for the HL-LHC was produced at CNM with small pixel sizes of 50 × 50 and 25 × 100 μm2, matched to the FE-I4 chip. They demonstrated a good performance in the laboratory and in beam tests with hit efficiencies of about 97% at already 1–2 V before irradiation.

3D sensors for the HL-LHC

In order to increase its discovery potential, the Large Hadron Collider (LHC) accelerator will be upgraded in the next decade. The high luminosity LHC (HL-LHC) period demands new sensor technologies to cope with increasing radiation fluences and particle rates. The ATLAS experiment will replace the entire inner tracking detector with a completely new silicon-only system. 3D pixel sensors are promising candidates for the innermost layers of the Pixel detector due to their excellent radiation hardness at low operation voltages and low power dissipation at moderate temperatures. Recent developments of 3D sensors for the HL-LHC are presented.

arXiv : Radiation hardness of small-pitch 3D pixel sensors up to HL-LHC fluences

A new generation of 3D silicon pixel detectors with a small pixel size of 50 (times ) 50 and 25 (times ) 100 (upmu )m(^{2}) is being developed for the HL-LHC tracker upgrades. The radiation hardness of such detectors was studied in beam tests after irradiation to HL-LHC fluences up to (1.4times 10^{16}) n(_{mathrm {eq}})/cm(^2). At this fluence, an operation voltage of only 100 V is needed to achieve 97% hit efficiency, with a power dissipation of 13 mW/cm(^2) at (-25,^{circ })C, considerably lower than for previous 3D sensor generations and planar sensors.