Design and Performance of the GERDA Low-Background Cryostat for Operation in Water

Abstract

In searching for the neutrinoless double-beta decay of ${}^{76}$Ge the GERmanium Detector Array (GERDA) experiment at the INFN Laboratori Nazionali del Gran Sasso has achieved an unprecedented low background of well below 10${}^{-3}$ cts/(keV$\cdot$kg$\cdot$yr) in the region of interest. It has taken advantage of the first realization of a novel shielding concept based on a large cryostat filled with a liquid noble gas that is immersed in a water tank. The germanium detectors are operated without encapsulation in liquid argon. Argon and water shield the environmental background from the laboratory and the cryostat construction materials to a negligible level. The same approach has been adopted in the meantime by various experiments. This paper provides an overview of the design and operating experience of the 64 m${}^3$ liquid argon cryostat and its associated infrastructure. The discussion includes the challenging safety issues associated with the operation of a large cryostat in a water tank.

33 pages, 13 figures, 8 tables

References in corpus (3)

• Leptogenesis
• The Large Underground Xenon (LUX) Experiment
• The GERDA experiment for the search of 0νββ decay in ^{76}Ge

Cited by in corpus (2)

• Final Results of GERDA on the Two-Neutrino Double-$\beta$ Decay Half-Life of ${}^{76}$Ge
• Search for tri-nucleon decays of ${}^{76}$Ge in GERDA