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This Year – RICH,TOF Patch,SVT,FTPC. RICH and TOF: Increase K identification in p t over a limited geometric acceptance Centered at mid-rapidity they provide complimentary pt coverage TOF patch 0.3< p t <1.5 GeV/c RICH 1.1 < p t < 3.0 GeV/c
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This Year – RICH,TOF Patch,SVT,FTPC RICH and TOF: Increase K identification in pt over a limited geometric acceptance Centered at mid-rapidity they provide complimentary pt coverage TOF patch 0.3< pt <1.5 GeV/c RICH 1.1 < pt < 3.0 GeV/c Overlaps with the TPC kink and dE/dx measurement kink pt < 5 GeV, dE/dx pt < 0.8 GeV SVT: Increased efficiency for all strange particles and resonances due to improved tracking Should measure spectra for all particles this year. HBT with strange particles Exotica FTPC: Strange particles at high y
SVT STAR detector gets new silicon heart – CERN Courier SVT installed and operational April 2001!! 91% live (out of 103,680 channels) 6% of the detector read out if set noise level to 4 mV
SVT details Radiation Length 1.5%/layer (including Electronics+Cooling) 216 wafers on 36 Ladders 0.7m2Silicon Radii – 5,10 15 cm Length ±12.4 cm ± 18.6 cm ± 21.7cm (-1 < h < 1)
Principle of Operation Ionizing particle Y-position from readout anode number SDD X-position from drift time X Electron cloud SDD gives unique position in X-Y * 6.3 cm x 6.3 cm area * 280 mm thick n-type Si wafer * 20 mmposition resolution
SVT Performance Noise 1ch=2mV Cosmic Ray Event–L3 Trigger Threshold at 4mV 6% live Hits from Au-Au Event
Drift Velocity Calibration SDD’s modeled using 2 drift velocities. One in the drift region and one in the focusing region There is a temperature dependence across the wafer which must be accounted for. Residuals as a function of drift distance from E896 data Haven’t quite got focusing region correct
Calibrations - Pedestals First Time bucket Other 127 Time buckets Anode You can see the edges of the 15 PASA’s and more obviously the 3 analogue buffers where the multiplexing occurs M.Munhoz
Calibrations – Pedestals(2) Have noise at 1st capacitor and in 1st time bucket 1st capacitor is more of a“problem” because it is in a random position each event. 1st time bucket doesn’t contain data You can see the first time bucket noise and the first capacitor glitch M. Munhoz
The PASA response function After passing through the PASA the signal in the time direction is no longer gaussian, the Laplace transform of the response function is: Where ts~11.5ns, tl ~500ns In the time domain this has the extended form: Where a = 1/ts and b =1/ tl, and c = b-a Peaking time 100ns Width 50 ns
Fitting the PASA response fn(2) Fitting the PASA response function to real (many times) MIP hits. You can see a) the fit is good b) the broadening of the hit as the drift time increases. E896 – G Lo Curto