Abstract
Experiments searching for the neutrinoless double beta (0vbb) decay require a very low and well understood background because of the expected long half-lives. GERDA investigates the 0vbb-decay, a part of this background is due to the capture of muon induced neutrons on the 76-Ge nuclei within the germanium diodes. The decay of the created 77-Ge nuclei could be misinterpreted as 0vbb-signal. If the moment of the neutron capture is known, the decay can be suppressed by introducing a sufficiently long dead time. The capture is revealed by the prompt gamma-cascade that releases the binding energy gained. The prompt radiation itself contributes to the overall background in the GERDA experiment as well. So far the prompt cascade was not well known. The spectrum of the 76-Ge(n,gamma) reaction was measured using the instrument for “Prompt Gamma Activation Analysis” (PGAA) at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRMII) in Garching to obtain the energies and intensities of the prompt transitions in 77-Ge. In a second measurement coincidences between these lines were determined to reconstruct the decay scheme. For a quantitative estimation of the background in GERDA the neutron capture propability for 76-Ge, i.e. its cross section, was determined by the activation method. Similar measurements were carried out for the 74-Ge isotop, present in the GERDA diodes as well.
Author and committee
dc:creator, dc:contributor.*- Author
-
- Meierhofer, Georg
Identifiers
dc:identifier.*- Identifier
- hdl:10900/49519