GENIUS-TF

Introduction

GENIUS-TF is a test-facility for the GENIUS project, which has been proposed aiming at a dramatic increase of the sensitivity in the field of dark matter and double beta decay search. It suggests to operate conventional High-Purity Germanium (HPGe) detectors directly in liquid nitrogen. This has the advantage that the background can be lowered by three or four orders of magnitude with respect to the same detectors operated in the usual way (e.g. the Heidelberg-Moscow experiment), essentially by removing most of the material in the vicinity of the detectors.

The GENIUS experiment would have the potential to look for Dark Matter, covering the major part of the MSSM parameter space predicted for neutralinos as cold dark matter candidates (also by looking for the annual modulation effect). The sensitivity of GENIUS for searching the neutrinoless double-beta decay of 76Ge would reach the level of about 0.01 eV mass range. Moreover, by using 100 kg of enriched 76Ge (the same material we have now in our Heidelberg-Moscow experiment), GENIUS would allow to confirm the present indication for neutrinoless double beta decay with a confidence level of 7 sigma after 3 years of measurement.

It was suggested by the Scientific Committee of LNGS to build up a small GENIUS test facility (GENIUS-TF) before realizing the final large setup. This would allow to test important prerequisits for the realization of the GENIUS experiment, such as:

Long term stability of the detectors in liquid nitrogen
Stability of the low-energy spectrum to mechanical vibrations (microphonic noise)
Implementation of the detector holder system
Data acquisition system The GENIUS Test Facility is at present under construction between hall A and B at LNGS.

The final version foreseen for the test facility consists of 40 kg of natural Ge detectors in a box of liquid nitrogen (see Fig.1).

The setup will start operation in early 2003 with 4 detectors (about 10 kg of Ge) and a new digital data acquisition system which has been recently developed especially for GENIUS-TF.

Fig.1 Schematic view of the GENIUS-TF setup

Fig.2 Potential of GENIUS for exploring the MSSM parameter space

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