1. Few introductory remarks on topical meetings…

2. System safety review 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, 2 nd opinion, …) Intense discussions: BSK vs. 3 rd wall Pragmatic conclusion (Sep 5/9 meetings): study of feasibility of 3 rd 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 3 rd wall Presentation to LNGS SC, Oct 14

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 & 3 rd wall at Tuebingen meeting  Review WT/CT/3 rd wall design  Make sure that 3 rd wall has no impact on physics performance  Make sure that 3 rd wall has no/minimal impact on WT or CT  If flaws of design appear, still in time to fix  If possible, take decision for 3 rd 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/cm 3, 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?