Post on 30-Mar-2015
Cosmic Ray Test of Cosmic Ray Test of GEM-MPI/TPC in Magnetic FieldGEM-MPI/TPC in Magnetic Field
Hiroshima UniversityKuroiwa
CDC Group
Mar. 4. 2005
MPGD-Readout TPCMPGD-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
Requirement
Spatial resolution
σx < 150μmσz < 1mm
Two-track sep.
Δ2hit < 2mm
GEM as the Readout MPGDGEM 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/TPCGEM-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/TPCGEM-MPI/TPC GEM
– 10cm×10cm– Cu electrodes 5μm thick– Bi-conical holes due to chemical etching (CERN)– 3 GEM plane– VGEM : 320V
GEM-MPI/TPCGEM-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
6mm
2mm
0.3mm0.3mm
Experimental SetupExperimental Setup Setup
– Trigger : scintillation counter×3 , 10×27cm– E-field : 300V/cm– B-field : 1T– VGEM : 320V
– Gas : TDR
ResultResult X resolution (Row 1)
nominal residual (σn.r.) from track without self info
Row 1 has the worst tracking error in all rowsgeometric meanσ = sqrt(σn.r.・ σfull) σfull : from track with self info
ResultResult 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 SizePad Size
Change the pad width
Pad width : 2mm Pad width : 1mmproduced by the end of March
Beam test at KEK-PS in April and June
Summary and PlanSummary 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