Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 93: Neutrino physics without accelerators IV

T 93.1: Vortrag

Donnerstag, 18. März 2021, 16:00–16:15, Tr

Charge-carrier collective motion in germanium detectors for ββ-decay searches — •Tommaso Comellato, Matteo Agostini, and Stefan Schönert — Physik-Department, Technische Universität München, Garching

The state-of-the-art technology in germanium crystals allows the production of detector blanks with lengths and diameters of 10 cm, and a level of impurities in the range of 10¹⁰ atoms/cm³. Such crystals can be converted into High Purity Germanium (HPGe) detectors. In such devices, the time structure of the signal can be used to discriminate the topology of the energy deposition. This is exploited in the search for neutrinoless double beta decay (0νββ) of ⁷⁶Ge, where HPGe detectors enriched in ⁷⁶Ge are used simultaneously as source and detector (Gerda, Legend). In the effort to enlarge the detector dimensions, new geometries such as the Inverted Coaxial have been recently developed [1]. In this new type of detectors the time needed to collect charge carriers is much larger than the detectors used in the current 0νββ experiments. Longer collection times lead to the observation of subleading effects in the signal formation due to the self-interaction of the charge-carriers’ clusters during their migration. In this talk I will present the impacts that such effects have on signal shape and on pulse shape discrimination performance, as we describe in [2]. This work has been supported in part by the ERC (Grant agr. No. 786430 - GemX) and by the SFB1258 funded by the DFG.

[1] R. J. Cooper et al., Nucl. Instrum. Meth. A665 (2011) 25

[2] T. Comellato et al., arXiv: 2007.12910 (2020)