Updates on the Micromegas + GEM prototype Fri, 21st August 2009 – CERN Marco Villa Athanasios Chouliaras Sinem Salva

Detector schematic GEM specifications: Micromegas specifications: Drift mesh 10x10 cm2 3.25 mm Standard GEM foil 2.2 mm Micromegas mesh 0.128 mm Anode Micromegas specifications: 45 µm mesh pitch 18 µm mesh wire diameter 2.5 cm pillar pitch 300 µm pillar diameter GEM specifications: hexagonal hole geometry biconical holes 140 µm hole pitch 70 µm hole outer diameter 50 µm inner diameter 50 µm kapton thickness 5 µm copper thickness

Energy resolution Gas mixture Ar/CF4 90/10 drift field 0.62 kV/cm GEM voltage 325 V transfer field 1.25 kV/cm

Gain Gas mixture Ar/CF4 90/10 drift field 0.62 kV/cm GEM voltage 325 V transfer field 1.25 kV/cm

Alphas current Gas mixture Ar/CF4 90/10 drift field 0.62 kV/cm GEM voltage 325 V transfer field 1.25 kV/cm

New detector schematic Drift mesh 10x10 cm2 3.3 mm Micromegas mesh 0.128 mm Anode Micromegas specifications: 45 µm mesh pitch 18 µm mesh wire diameter 2.5 cm pillar pitch 300 µm pillar diameter

Energy resolution Gas mixture Ar/CF4 90/10 drift field 1.25 kV/cm