Irradiation of DEPFET-like transistors with Co-60 gamma source up to 10 MRad

TL;DR

This study assesses the radiation tolerance of DEPFET-like transistors used in the Belle II Pixel Detector by irradiating sixty devices with Co-60 gamma rays up to 10 MRad, analyzing their performance under various conditions.

Contribution

It provides the first comprehensive evaluation of DEPFET transistor resilience to high-dose gamma irradiation up to 10 MRad, considering different device parameters.

Findings

DEPFET devices remain functional after 10 MRad irradiation

Performance varies with doping types and biasing conditions

Data informs detector design for high-radiation environments

Abstract

The Pixel Detector (PXD) of the Belle II experiment at superKEKB accelerator in Japan is based in the DEPFET technology. Two layers of 8+12 modules at a radius of 13 and 22 mm will give a spatial resolution below 10 mm. The radiation level expected in the first layer in ten years of operation is about 10 MRad of total ionizing dose. In order to study the tolerance of the DEPFET technology sixty devices were irradiated using a standard procedure like 60Co gamma source. Different doping types, channel sizes and biasing conditions were studied