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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, - PowerPoint PPT Presentation
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LAST 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 LAL Orsay
K. Sachs, Carleton University Ottawa,
Ph. Rosier, J. Pouthas, T.Zerguerras, IPN Orsay
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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chamber diameter 50 cm length 50 cm
Berkeley Saclay Orsay
mesh
50 m pitch
50 m gap
readout anode pad plane
1024 pads
2x10 mm2pads
CHAMBER DESIGN AND PAD LAYOUT
1x10 mm2pads
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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new data acquisition in April-May 2004:
superconducting magnet runs at 0.1, 0.3, 0.5, 0.7, 1, 1.5 & 2 Tesla
trigger: 2-3 fold scintillator10 – 50 % efficiency (lower at high fields)
gases: Ar + CF4 / CH4/ iso-C4H10
10% 3% 5%
data acquisition: X20
2004 COSMIC RAY RUN
online event display
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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GOOD NEWS GOOD NEWS
0
100
200
300
400
500
600
0 0,5 1 1,5 2
Ar CF4
Ar Iso
Ar CH4
Magnetic field (T)
Ave
rage
am
plit
ude
sum
after investigation…
it was due to an error in the analysis !!!
no effect of B on the amplitude!
wrong!!!
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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dE/dX vs particle momentum10 cm Ar-
5%isobutane
momentum distribution
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
relativistic rise clearly visible
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effect of the transverse diffusion
z= 45cmz= 39cmz= 33cm
z= 25cmz= 18cmz= 12cm
P10 gas@ 0.5T
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
σ2 (width) increasing with drift distance
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track width vs zP10 [email protected]
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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track width vs zAr-3%CF4 gas
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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Ar+3% CF4 results
track width vs drift distance
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
B=0.3 T
0.5 T
0.7 T
1.0 T
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transverse diffusion: 10-15% less measured diffusion than calculated by Magboltz B measurement calculationP10@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 8680 86
Ar-5%iso @221V/cm
0.1T 388 449
0.3T 308 355
0.5T 254 284
1T 177 193
1.5T 131 146Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
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transverse diffusion: 10-15% less measured diffusion than calculated by Magboltz B measurement calculationP10@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 8680 86
Ar-5%iso @221V/cm
0.1T 388 449
0.3T 308 355
0.5T 254 284
1T 177 193
1.5T 131 146Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
200μm @4T @1m!
potential transverse point resolution of 25μm
at 1m
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CONCLUSIONS
Vincent Lepeltier ILCD Collaboration meeting January 14th 2005
the Berkeley-Orsay-Saclay Micromegas TPC has been working well and has taken good data last Springanalysis 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.
