title: LArGe - A liquid argon scintillation veto for GERDA creator: Heisel, Mark subject: ddc-530 subject: 530 Physics description: LArGe is a Gerda low-background test facility to study novel background suppression methods in a low-background environment, for possible applications in the Gerda experiment. Gerda searches for the neutrinoless double-beta decay in Ge-76, by operating naked germanium detectors submersed into 65 qm of liquid argon. Similarly, LArGe runs Ge-detectors in 1 qm (1.4 tons) of liquid argon, which in addition is instrumented with photomultipliers to detect argon scintillation light. The light is used in anti-coincidence with the germanium detectors, to effectively suppress background events that deposit energy in the liquid argon. This work adresses the design, construction, and commissioning of LArGe. The background suppression efficiency has been studied in combination with a pulse shape discrimination (PSD) technique for various sources, which represent characteristic backgrounds to Gerda. Suppression factors of a few times 10^3 have been achieved. First background data of LArGe (without PSD) yield a background index of (0.12-4.6)·10^-2 cts/(keV·kg·y) (90% c.l.), which is at the level of the Gerda phase I design goal. Furthermore, for the first time we measure the natural Ar-42 abundance (in parallel to Gerda), and have indication for the 2nubb-decay in natural germanium. date: 2011 type: Dissertation type: info:eu-repo/semantics/doctoralThesis type: NonPeerReviewed format: application/pdf identifier: https://archiv.ub.uni-heidelberg.de/volltextserver/11921/1/DissertationHeisel.pdf identifier: DOI:10.11588/heidok.00011921 identifier: urn:nbn:de:bsz:16-opus-119216 identifier: Heisel, Mark (2011) LArGe - A liquid argon scintillation veto for GERDA. [Dissertation] relation: https://archiv.ub.uni-heidelberg.de/volltextserver/11921/ rights: info:eu-repo/semantics/openAccess rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html language: eng