Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 14: Pixel detectors I

T 14.4: Vortrag

Montag, 15. März 2021, 16:45–17:00, Tn

Evolution of currents in irradiated DEPFET sensors — •Marike Schwickardi¹, Ariane Frey¹, Benjamin Schwenker¹, Botho Paschen², Georgio Giakoustidis², and Harrison Schreeck¹ — ¹II. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Deutschland — ²Physikalisches Institut Uni Bonn, Nußallee 12, 53115 Bonn

The Belle II experiment at the Japanese Super B-factory SuperKEKB has started data taking in early 2019, the peak luminosity will be ramped up to 8·10³⁵cm⁻²s⁻¹, which is 40 times higher than the previous luminosity at the Belle experiment, which was therefore upgraded with a new DEpleted P-channel Field Effect Transistor (DEPFET) based silicon pixel detector (PXD) for vertex detection. The silicon bulk, on which the field-effect transistors form the individual pixels, is biased by different voltages enabling bulk depletion, charge collection and charge removal.

Due to the much harsher environment, the radiation hardness of the equipped sensors in the PXD has to be well understood and is investigated. Especially, since during operation in the Belle II environment with only small neutron fluences, an increase in the bulk depletion current could be observed. Therefore, x-ray irradiation studies were conducted to investigate the current behaviour of the sensors. This talk will present observations on the sensor performance during an irradiation campaign with doses of up to 18.5 Mrad in the silicon oxide.