[en] Electron anti-neutrinos (ν-bar_e) emitted from distant (∼ 800 km) nuclear reactors will be measurable with the BOREXINO detector at the Gran Sasso Underground Laboratory. From this signal neutrino oscillation parameters can be assessed for Δm² > 10^-6 eV² and sin² 2Θ > 0.3. In particular one of the currently favoured Δm² - sin² 2Θ parameter regions, i.e. the large mixing angle MSW solution which is proposed in order to resolve the solar neutrino problem, can be tested for the first time in a terrestrial laboratory experiment. The impact of non-reactor ν-bar_e's, in particular the signal of geo-physical neutrinos and potential backgrounds are discussed

[en] The objective of the BOREXINO project is to measure the solar ⁷Be neutrino flux. The current status of the experiment is reviewed and recent results achieved with the Counting Test Facility (CTF) at Gran Sasso are presented. (author)

[en] We comment on the first indication of geo-neutrino events from KamLAND and on the prospects for understanding Earth energetics. Practically all models of terrestrial heat production are consistent with data within the presently limited statistics, the fully radiogenic model being closer to the observed value (∼9 geo-events). In a few years KamLAND should collect sufficient data for a clear evidence of geo-neutrinos, however discrimination among models requires a detector with the class and size of KamLAND far away from nuclear reactors. We also remark that the event ratio from thorium and uranium decay chains is well fixed N(Th)/N(U)≅0.25, a constraint that can be useful for determining neutrino oscillation parameters. We show that a full spectral analysis, including this constraint, further reduces the oscillation parameter space compared to an analysis with an energy threshold E_vis>2.6 MeV

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[en] The physics goals of BOREXINO and of future low energy solar neutrino projects are summarized and experimental challenges discussed. In the near future, ⁷Be and conceivably pep neutrinos will be measured via neutrino electron scattering. On the long term, direct measurements of the primary pp neutrino flux appears feasible. (author)

[en] The LENS experiments will measure energy resolved sub-MeV solar electron-neutrinos (ν_e) in real time via inverse β-transition populating an isomeric state in the daughter nuclei. The subsequent de-excitation provides a delayed coincidence tag which discriminates against background. A liquid scintillation detector loaded with 20 t of Yb would yield an event rate of 190 pp- and 175 ⁷Be neutrinos per year. Essential information on neutrino mixing and masses can be derived. (author)

[en] Borexino will look for low energy solar neutrinos while GERDA is designed to search for neutrinoless double beta decay of 76Ge. Radioactive noble gases of atmospheric origin present as traces in nitrogen or argon can significantly contribute to the background in these experiments. The most important are ³⁹Ar, ⁸⁵Kr and ²²²Rn. Nitrogen is used in Borexino for scintillator purification and blanketing, LAr will serve in GERDA as a passive/active shield and as a cooling medium for the Ge crystals. Concentrations of ³⁹Ar, ⁸⁵Kr and ²²²Rn in nitrogen must be below 0.5, 0.2 and 7 μBq/m³ (STP), respectively. Rn concentration in the argon used in GERDA should be below 0.5 μBq/m³ (STP). We found such extremely pure nitrogen on the market and simulated experimentally the supply chain between a supplier and a customer in order to prove that it is possible to keep the purity under control. We discuss the obtained results and applied measurement techniques. Results of Ar purification tests from ²²²Rn, its oncentration measurements in a gas of different quality are also shown and compared with those obtained for nitrogen. Rn emanation from storage tanks is also discussed. (orig.)

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No abstract available