Mainz 2012 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 3: Astroteilchenphysik
HK 3.4: Talk
Monday, March 19, 2012, 15:00–15:15, RW 3
Correlated and Accidential Background induced by Radioimpurities in Double Chooz — •Michael Franke, Franz von Feilitzsch, Marianne Göger-Neff, Martin Hofmann, Lothar Oberauer, Patrick Pfahler, Walter Potzel, Stefan Schönert, and Vincenz Zimmer — Lehrstuhl E15, Technische Universität München
Since April 2011, the reactor νe disappearance experiment Double Chooz is successfully taking data with the far detector. To allow a measurement of the neutrino mixing angle ϑ13, the precise determination of the νe flux and its spectral shape is important. To achieve the desired precision, several sources of background have to be taken into account and investigated. The talk will focus on the background induced by radioactivity in the detector. The major contribution comes from accidential νe-like events and (α,n) reactions on 13C as part of the correlated background. The selection cuts applied to the raw data to extract the events of interest will be presented, as well as the BiPo coincidences search. The latter method shows that the radiopurity in Double Chooz is well within the specifications of less than 10−13 g/g of U and Th in all parts of the inner detector. The rate of accidential coincidences is far below the design goal of one event per day, too. However, these events cannot be neglected for an measurement of ϑ13 and have to be addressed in further ongoing studies.
This work has been supported by founds of the DFG (Transregio 27: Neutrinos and beyond), the Excellence Cluster Universe and the Maier-Leibnitz-Laboratorium Garching.