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Cosmic Ray Test of GEM-MPI/TPC in Magnetic Field. Hiroshima University Kuroiwa CDC Group. Mar. 4. 2005. MPGD-Readout TPC. TPC MWPC (Multi Wire Proportional Chamber) readout Two-track separation capability > 1cm MPGD (Micro Pattern Gas Detector) readout GEM , MicroMEGAS
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Cosmic Ray Test of GEM-MPI/TPC in Magnetic Field Hiroshima University Kuroiwa CDC Group Mar. 4. 2005
MPGD-Readout TPC • TPC • MWPC (Multi Wire Proportional Chamber)readout • Two-track separation capability > 1cm • MPGD (Micro Pattern Gas Detector) readout • GEM , MicroMEGAS Performance test of GEM-TPC by cosmic ray
GEM as the Readout MPGD • Almost no E×B effects ⇒ good spatial resolution • Fast and spatially narrow induced signals ⇒ good two-track separation • No wire ⇒ thin sector boundaries • Suppression of positive ion feedback
GEM-MPI/TPC • MPI/TPC • Field cage : Maximum drift length = 27cm • Pad plane : 10cm×10cm • Gas : TDR (Ar : CH4 : CO2 = 93 : 5 : 2) • Readout : MWPC ⇒ GEM
GEM-MPI/TPC • GEM • 10cm×10cm • Cu electrodes 5μm thick • Bi-conical holes due to chemical etching (CERN) • 3 GEM plane • VGEM : 320V
6mm 2mm 0.3mm 0.3mm GEM-MPI/TPC • Pad • Pad plane : 12×64 pads cover 10cm×10cm • Pad size : 2mm×6mm (0.3mm gap) • Readout channels : 7 pad rows×12 pads
Experimental Setup • Setup • Trigger : scintillation counter×3 , 10×27cm • E-field : 300V/cm • B-field : 1T • VGEM : 320V • Gas : TDR
Result • X resolution (Row 1) nominal residual (σn.r.) from track without self info Row 1 has the worst tracking error in all rows geometric mean σ = sqrt(σn.r.・σfull) σfull : from track with self info
Result • X resolution (Row 6) nominal residual tracking error is small in the middle row geometric mean σ shows almost same behavior as the row 1 Effect of large-pad size
Pad Size • Change the pad width Pad width : 2mm Pad width : 1mm produced by the end of March Beam test at KEK-PS in April and June
Summary and Plan • Summary • Geometric mean of row 1 and row 6 show almost same behavior. • Effect of large-pad size • Plan • 1mm pad • Cosmic ray test • Beam test at KEK-PS in April and June • GEM , MicroMEGAS