My personal Resumé Very interesting work-shop, stimulating atmosphere and very good discussions. Accommodation is excellent. For the Straw Project we have accomplished quite a bit. – Many decisions – Many points clarified, and brought forward Not complete, not objective

Operation test-beam/simulation Very encouraging results MC studies (gas versus missing mass) are very instructive My conclusion: – Baseline gas mixture is preferred, but both gas mixtures could be used. – High Rate measurements are very encouraging – For Peter L. close exchange with Sergei, Anatoli and Dimitri will clarify several points...

Electronics Electronics: – Many interesting points raised by Peter: falling edge -> trigger X-talk, termination, impedance matching,... – DAQ : 3 options presented Need clarification of requirements: monitoring signals, separation DAQ/DCS, central or local (Peter discuss with Marco, Valeri, Hans...) Comparison of cost and effort for options considered Time line (1 year for PCB development) ??

Straw Mounting End plugSpacerComment Endplug mounted during straw production Mylar foilEnd plug assembly accuracy insufficient. Mounting during straw installation Mylar foilMylar support σ≈100μm No full size prototype yet Humidity -> Mylar ? Endplug mounted during straw production Wire-Ultem ringIncompatible Mounting during straw installation Wire-Ultem ringUltem spacer σ≈50μm End plug σ≈100μm Decision: option 4 is not ideal, but is adopted because of tight schedule. End plugs and Straw supports (spacers)

Straw Mounting Accuracy ArgumentRequired limitPossible mitigations Straw Operation Properties < 500 μm Hermiticty of Detector< 200 μm (with respect to neighbouring straw) higher straw density Electrostatic Forces< 100 μm (?) (with respect to wire centre) Individual wire alignment or wire supports (?) Action list: 1.MC study efficiency impact.. For 2two different R eff = 4.7 and 4.5 ?? Simulate prototype -> understand difference inR eff ???? 2.Check drop off of efficiency (measured with 1 Straw only). Note: change of layout means a significant design effort. Decision: no design change (if not strong evidence from MC for inefficiency ) => Hans confirmed assembly accuracy limit (±100μm Peak to peak) Decision: no design change (if not strong evidence from MC for inefficiency ) => Hans confirmed assembly accuracy limit (±100μm Peak to peak)

Orientation of Stations Decide to swap the views.. – 1 st u-v – 2 nd x-y

Frame OptionAction items Assembled frameMechanical calculations tbd. Massive aluminium frame Machining precision cost Mech. calculations Decision: 1.Study both options 2.Chamber layout should be kept unchanged for both versions Decision: 1.Study both options 2.Chamber layout should be kept unchanged for both versions Remarks from closed session: Decide on Assembled or monolithic option by Feb Integration issues (Solution A or B) to be decided before Feb Dummy chambers are needed by end of 2011.

Welding Welding procedures improved (QC) – Progress for failure rate in pressure test (10 to3%) – Environmental conditions: keep dry Need to improve further the correlation of welding parameters with solidity of joint. – Tensile tests suggested by Stefano (very important). – Consider to replace pressure test by other parameters. – Target failure rate < 1‰ during 4 years at operation pressure. – Non straight straws (what selection criteria ?) Improve welding machine: – Polishing, form, material of anvil – Friction of machinery, scratches, Most critical in my view

Material Specify properties (requirements) for base material, treatment – 2 sided perhaps better for welding – 1 sided visibly better for coating – Treatment required for gluing side (end plug) Surprise: raw PET factor 100 higher permetaion than coated material ???? Coating what, how many layers ? – Related to permeation, welding, x-talk Time line ?

Time Plan for 1 st Chamber Material + Coating Welding param. Straw Prod. Order 15/03 /10 Order 15/03 /10 Start May 10 Start May 10 Straw /Wire Assembly Frame Chamber Design May 10 End Nov. 10 End Nov. 10 Chamber construct. End April 11 End April 11 Start Oct. 10 Start Oct. 10 PermeationElectronics Proposal

Thank You very much DUBNA.