Test beam Characterizations of 3D Silicon Pixel detectors

TL;DR

This paper reports the first characterization of 3D silicon pixel detectors assembled with the ATLAS front-end chip, demonstrating high efficiency, good charge collection, and spatial resolution in a pion beam test, highlighting their potential for high-radiation environments.

Contribution

First-time assembly and beam characterization of 3D silicon pixel detectors with the ATLAS readout, showing promising performance for use in radiation-heavy environments.

Findings

Full charge collection at low bias voltages (~10 V)

Efficiency of 95.9% for tracks parallel to electrodes

Efficiency of 99.9% at 15 degrees incidence

Abstract

3D silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrating into the bulk material in contrast to standard Si detectors with planar electrodes on its top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as for example the radiation environment expected in an LHC upgrade. For the first time, several 3D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here we report results on unirradiated devices with three 3D electrodes per 50 x 400 um2 pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9% +- 0.1 % for tracks parallel to the electrodes and of 99.9% +- 0.1 % at 15 degrees are measured. The homogeneity of the efficiency over the pixel area and charge sharing are characterized.