Characterization of proton irradiated 3D-DDTC pixel sensor prototypes fabricated at FBK

TL;DR

This study evaluates 3D-DDTC pixel sensors fabricated at FBK for the ATLAS upgrade, demonstrating their charge collection performance post-irradiation up to high proton fluences and analyzing charge loss mechanisms via simulations.

Contribution

It provides experimental results on irradiated 3D-DDTC sensors with different electrode configurations and uses TCAD simulations to explain charge loss mechanisms.

Findings

Sensors maintain good charge collection up to 2 x 10^15 neq/cm^2 irradiation.

Sensors operate at bias voltages around 100 V after irradiation.

TCAD simulations successfully explain charge loss mechanisms.

Abstract

In this paper we discuss results relevant to 3D Double-Side Double Type Column (3D-DDTC) pixel sensors fabricated at FBK (Trento, Italy) and oriented to the ATLAS upgrade. Some assemblies of these sensors featuring different columnar electrode configurations (2, 3, or 4 columns per pixel) and coupled to the ATLAS FEI3 read-out chip were irradiated up to large proton fluences and tested in laboratory with radioactive sources. In spite of the non optimized columnar electrode overlap, sensors exhibit reasonably good charge collection properties up to an irradiation fluence of 2 x 10**15 neq/cm2, while requiring bias voltages in the order of 100 V. Sensor operation is further investigated by means of TCAD simulations which can effectively explain the basic mechanisms responsible for charge loss after irradiation.