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T0 – TDR. 22 nd LHCC meeting; Open Session CERN, September 29, 2004 W.H.Trzaska (for T0 collaboration). Results and conclusions from the June 2004 comprehensive test run Milestones Cost estimate. Experimental set-up. PMTs. 25 m of cable. Main electronics. 6 m of cable.
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T0 – TDR 22nd LHCC meeting; Open Session CERN, September 29, 2004 W.H.Trzaska (for T0 collaboration) Results and conclusions from the June 2004 comprehensive test run Milestones Cost estimate CERN September 29, 2004
Experimental set-up PMTs 25 m of cable Main electronics 6 m of cable TRD Shoebox CERN September 29, 2004
Typical TOF spectrum obtained with a pair of identical detectors FWHM = 94 ps CERN September 29, 2004
Measured time resolution * With shoebox (worsens resolution by 20 ps) CERN September 29, 2004
Amplitudes • For easier comparison the areas under the peaks were normalized to 10000 • The amplitudes were taken with the same PMT and at the same HV, just the radiators were changed CERN September 29, 2004
Efficiency as function of threshold • At very low threshold values registration efficiency for particles entering perpendicular to the front surface of the radiator is simply proportional to the area of that surface: 100,75, 44% • If the threshold value has to be raised (noise from other detectors, deterioration of detectors or electronics, etc.) the 20 mm radiator may turn out to be the best choice due to its excellent response function CERN September 29, 2004
T0 Efficiency in p – p collisions CERN September 29, 2004
Backsplash spectrum (20 mm quartz) • The efficiency for backward particles is the same as for forward particles but they can be efficiently separated by adjusting the threshold value CERN September 29, 2004
backsplash Backsplash in 200 PYTHIA events T0-A T0-C Alla Maevskaia, INR RAS,Moscow FWD meeting 21.09.2004 Calculations by Alla Maevskaia
Conclusions I (physics) • For all reasons except the efficiency in p-p collisions the 20 mm radiator is by far the best choice. • excellent pulse shape • 1/4 MIP resolution! • The efficiency can be restored, for instance, by increasing the number of detectors in T0-A (next T0 upgrade) • Decision expected on Nov 2004 TB CERN September 29, 2004
Conclusion II (electronics) • We have prototype of the shoebox and of all key electronics (Vertex, MPD, MT, VDU, QTC) • shoebox should work for V0 as well • work on DCS in progress • readout test (full chain) in 2005 • Better pulse shape (20 mm radiator) reduces the dynamic range • use of off-the-shelf CFDs becomes possible • high threshold setting possible • stable performance CERN September 29, 2004
T0 mechanics milestones • No concern: • T0-C prototype ready • Integration completed • Waiting for freezing of RB24 parameters to complete the design and order the production • Production cycle 3-6 months • Should be completed in 2005 CERN September 29, 2004
T0 electronics milestones Main electronics Shoebox • No major concern: • Prototypes of all dedicated T0 electronics build and tested • Excellent test results • Close collaboration with V0: • PMT, front-end (next meeting 10/04) • trigger-specific electronics (11/04) • HV, LV, DCS? • T0 will use TOF readout(slightly modified) CERN September 29, 2004
Some solid dates for T0 • Nov 2004: Freezing radiator size • Dec 2004: Electronics Design Review (joint with V0) • Feb 2005: Detector module frozen; mechanics PRR • Sep 2005: Full chain readout test • Dec 2005: T0 Mechanics ready • Feb 2006: Electronics PRR • Jun 2006: T0-C ready for installation in ALICE; installation of electronics at CERN; tests of the installed T0-C • Dec 2006: T0-A ready for installation in ALICE; tests of the installed T0-A CERN September 29, 2004
T0 cost estimate: 318 kCHF CERN September 29, 2004
Referee question: delay vs. HV 1.5 ps / V CERN September 29, 2004