Data Acquisition and Analysis of the 76Ge Double Beta Experiment in Gran Sasso 1990-2003

Klapdor-Kleingrothaus, H. V.; Dietz, A.; Krivosheina, I. V.; Chkvorets, O.

Data Acquisition and Analysis of the 76Ge Double Beta Experiment in Gran Sasso 1990-2003

Authors

Klapdor-Kleingrothaus, H. V.

Dietz, A.

Krivosheina, I. V.

Chkvorets, O.

Description

Data acquisition in a long running underground experiment has its specific experimental challenges, concerning data acquisition, stability of the experiment and background reduction. These problems are addressed here for the HEIDELBERG-MOSCOW experiment, which collected data in the period August 1990 - May 2003. The measurement and the analysis of the data is presented. The duty cycle of the experiment was ~80%, the collected statistics is 71.7 kgy. The background achieved in the energy region of the Q value for double beta decay is 0.11 events/kg y keV. The two-neutrino accompanied half-life is determined on the basis of more than 100 000 events. The confidence level for the neutrinoless signal has been improved to a 4 sigma level.
Full version (50 pages, 36 figures, 9 tables), zipped ps file (size ~21MB or pdf format (size ~26MB), can be found in http://www.mpi-hd.mpg.de/non_acc/super.html (corrected typos) In press in NIM A, 2004