The Micromegas TPC: achievements and plans for future beam test Paul Colas, CEA/Irfu, U. Paris-Saclay

MM TPC achievements and plans Achievements so far PHASE 1 with single modules (2008-2010). Test various resistive coverlays (not resistive, ink, Carbon loaded kapton, and later Diamond-like Carbon); measure point resolution. PHASE 2 multi-module (2011-2015). Miniaturize electronics, work out the whole chain demonstrate 0.25 X0 module thickness. Experience quasi-industrial production of 9 modules +2 more in 2014, and their readout Begin the study of alignment and distortions Test CO2 cooling 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans Z resolution 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans DISTORTIONS at B=O Beam test data with alignement 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans DISTORTIONS at B=1T 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans PLANS FOR A 3rd PHASE This must be at minimum cost (no funding before the green light from Japanese gov.) and with cost reduction in mind. 3 or 4 new modules Solve connection pb Cooling: 1 loop ‘GEM’ backframes NEW GROUNDING SCHEME Adaptable GEM gate 06/12/2016 MM TPC achievements and plans

New voltage distribution to avoid distortions Grounded mesh In contact with backframe Resistive layer - 380 V High eR insulator Pads grounded through electronics Such a scheme has already been used elsewhere and found to be good for noise suppression The ‘insulator’ might require R&D This scheme allows re-using most components (GEM back-frames, AFTER TPC electronics, etc…) 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans 2P CO2 cooling Go to 1 loop for 3 to 4 modules (avoids ‘clarinettes’ which were there for robustness in case of leak on one module) 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans Adapt a GEM gate Learning from our Japanese colleagues, we plan to adapt a GEM gate on top of the modules Two options : simple frame glued on top of the module (but this gives radial cracks), or two stiff supports tied to the inner and outer circular boundaries of the module (à-la-Saga) 06/12/2016 MM TPC achievements and plans

MM TPC achievements and plans Conclusion A new phase is starting for MM tests, adapted to continue the developments while expecting the green light for the ILC construction. We are open to a broad collaboration Last step before a large module with new electronics Thanks to D. Attié, S. Ganjour (Saclay), D.S. Bhattacharya, S. Mukhhopadhyay (Kolkata), A. Bellerive, R. Mehdiyev (Carleton)… and many others Thanks for support from CEFIPRA project 4801 and E-JADE. 06/12/2016 MM TPC achievements and plans