Few introductory remarks on topical meetings…

1. Few introductory remarks on topical meetings…

2. System safety review Presentation to LNGS SC, Oct 14 • Dense schedule of meetings with LNGS and safety experts during last six months • Various documents and studies performed in collaboration with external experts (TDR, FMECA, HAZOP, TÜV, 2nd opinion, …) • Intense discussions: BSK vs. 3rd wall • Pragmatic conclusion (Sep 5/9 meetings): study of feasibility of 3rd wall in close co-operation with LNGS and implement if ► performance of the experiment not compromised ► within financial capabilities of collaboration • Under study: Cu and Lexan • Safety concept of GERDA accepted by LNGS with implementation of 3rd wall

3. Discussion within management team after LNGS SC meeting: • Proceed with water tank tender submission to INFN council in October • Organize topical meeting on WT/Cryo-tank & 3rd wall at Tuebingen meeting • Review WT/CT/3rd wall design • Make sure that 3rd wall has no impact on physics performance • Make sure that 3rd wall has no/minimal impact on WT or CT • If flaws of design appear, still in time to fix • If possible, take decision for 3rd wall material/design at this meeting • Move on with maximum speed to start WT and CT construction

4. Topical meeting on LAr vs. LN • LN design based on our experience of radio purity, liquid/gas handling, supply chain quality control • LAr considered interesting alternative (=1.4 g/cm3, bp: 10 K above LN, scintillator) • Review advantages and disadvantages of LAr and LN Do we have all information needed to make choice? If not, come up with ‘to do list’ Does design of particular hardware need early decision? (e.g. Cryogenic system?) Is change at later time possible/realistic/needed?