Karlsruhe 2024 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
T: Fachverband Teilchenphysik
T 113: Silicon trackers 6
T 113.3: Vortrag
Freitag, 8. März 2024, 09:30–09:45, Geb. 30.22: kl. HS B
Investigation of high backside currents in DePFET pixel sensors for the Belle II experiment using dedicated test-structures — Florian Bernlochner, Jochen Dingfelder, •Georgios Giakoustidis, and Botho Paschen — University of Bonn, Germany
For the Belle II experiment at KEK (Tsukuba, Japan) the KEKB accelerator was upgraded to deliver e+e− collisions at a center of mass energy of ECM = 10.58 GeV and it has reached a record-breaking instantaneous luminosity of 4.7·1034 cm−2s−1. During the so-called Long Shutdown 1 (LS1) the innermost part of the Belle II detector, the initially descoped PiXel Detector (PXD1) with 20 modules, based on Depleted P-channel Field Effect Transistor (DePFET) technology, was replaced by a fully-populated, two-layer PXD with 40 modules. As the detector closest to the experiment’s interaction region, PXD is most exposed to radiation from the accelerator. Throughout the operation of the PXD1 a steady increase of backside current with irradiation was observed in several modules. Doping profile measurements and electric field simulations show that this is a consequence of (partially) shorted guard-rings at the backside leading to high electric fields and avalanche current multiplication. Irradiation results of dedicated test-structures to further investigate the mechanism will be presented.
Keywords: DEPFET; PXD; Belle II; SuperKEKB