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L A ST RESULTS OF THE BERKELEY-SACLAY-ORSAY TPC COSMIC-RAY TESTS. P. Colas , C. Coquelet, E.Delagnes, A.Giganon, Y.Giomataris , J.-P. Robert, DAPNIA-CEA Saclay F. Bieser, M.Ronan LBNL Berkeley R. Cizeron, G. Guilhem, V.Lepeltier L AL Orsay K. Sachs, Carleton University Ottawa,
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LAST RESULTSOF THE BERKELEY-SACLAY-ORSAY TPC COSMIC-RAY TESTS P. Colas, C. Coquelet, E.Delagnes, A.Giganon, Y.Giomataris, J.-P. Robert, DAPNIA-CEA Saclay F. Bieser, M.RonanLBNL Berkeley R. Cizeron, G. Guilhem, V.LepeltierLAL Orsay K. Sachs, Carleton University Ottawa, Ph. Rosier, J. Pouthas, T.Zerguerras, IPN Orsay Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
CHAMBER DESIGN AND PAD LAYOUT Berkeley Saclay Orsay chamber diameter 50 cm length 50 cm readout anode pad plane mesh 1024 pads 2x10 mm2pads 1x10 mm2pads 50 m pitch 50 m gap Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
2004 COSMIC RAY RUN new data acquisition in April-May 2004: superconducting magnetruns at 0.1, 0.3, 0.5, 0.7, 1, 1.5 & 2 Tesla trigger: 2-3 fold scintillator 10 – 50 % efficiency (lower at high fields) gases: Ar + CF4 / CH4/ iso-C4H10 10% 3% 5% data acquisition: X20 online event display Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
GOODNEWS after investigation… it was due to an error in the analysis !!! no effect of B on the amplitude! Average amplitude sum wrong!!! Magnetic field (T) Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
momentum distribution relativistic rise clearly visible dE/dX vs particle momentum 10 cmAr-5%isobutane Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
effect of the transverse diffusion σ2 (width) increasing with drift distance z= 12cm z= 18cm z= 25cm P10 gas@ 0.5T z= 33cm z= 39cm z= 45cm Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
track width vs z P10 gas@0.3T Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
track width vs z Ar-3%CF4 gas Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
Ar+3% CF4 results B=0.3 T 0.5 T 0.7 T 1.0 T track width vs drift distance Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
transverse diffusion: 10-15% less measured diffusion than calculated by Magboltz B measurement calculation P10@140V/cm 0.3T 224 µmxcm-1/2 308 µmxcm-1/2 0.5T 171 229 1T 105 140 Ar-3%CF4 @200V/cm 0.3T 184 202 1T 80 86 Ar-5%iso @221V/cm 0.1T 388 449 0.3T 308 355 0.5T 254 284 1T 177 193 1.5T 131 146 Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
transverse diffusion: 10-15% less measured diffusion than calculated by Magboltz B measurement calculation P10@140V/cm 0.3T 224 µmxcm-1/2 308 µmxcm-1/2 0.5T 171 229 1T 105 140 Ar-3%CF4 @200V/cm 0.3T 184 202 1T 80 86 Ar-5%iso @221V/cm 0.1T 388 449 0.3T 308 355 0.5T 254 284 1T 177 193 1.5T 131 146 200μm @4T @1m! potential transverse point resolution of 25μm at 1m Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
CONCLUSIONS the Berkeley-Orsay-Saclay Micromegas TPC has been working well and has taken good data last Spring analysis will be finalized soon (spatial resolution) plans for the future: 1/ charge spreading with a resistive foil on Micromegas: resolution tests very soon with the IPN-Orsay point-like e- source tests are planed with the Carleton TPC next spring in the Saclay 2T magnet 2/ hadron beam tests at KEK with the MPI TPC equipped with a Micromegas @1.2T next Spring (or Autumn?) 3/ new cosmic-ray measurements with the large B-O-S TPC at 2T? 4/development and test of «bulk» Micromegas (with woven mesh) at Saclay. Vincent Lepeltier ILCD Collaboration meeting January 14th 2005