1. CERN September 29, 20041W.H.Trzaska HIP Jyväskylä 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

2. CERN September 29, 20042W.H.Trzaska HIP Jyväskylä Experimental set-up 6 m of cable 25 m of cable PMTs Shoebox Main electronics Main electronics  TRD

3. CERN September 29, 20043W.H.Trzaska HIP Jyväskylä Typical TOF spectrum obtained with a pair of identical detectors FWHM = 94 ps

4. CERN September 29, 20044W.H.Trzaska HIP Jyväskylä Measured time resolution Radiator diameter FWHM TOF Sigma PMT 30 mm 122 ps  140 ps 37 ps  42 ps 26 mm 112 ps  128 ps 34 ps  39 ps 20 mm 94 ps  115 ps 28 ps  35 ps * With shoebox (worsens resolution by   20 ps)

5. CERN September 29, 20045W.H.Trzaska HIP Jyväskylä 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

6. CERN September 29, 20046W.H.Trzaska HIP Jyväskylä 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

7. CERN September 29, 20047W.H.Trzaska HIP Jyväskylä T0 Efficiency in p – p collisions Radiator diameter T0 configuration 12 - 1212 – 24 30 mm 53 % 20 mm 36 % 49 %

8. CERN September 29, 20048W.H.Trzaska HIP Jyväskylä 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

9. Calculations by Alla Maevskaia9 Backsplash in 200 PYTHIA events backsplash Alla Maevskaia, INR RAS,Moscow FWD meeting 21.09.2004 T0-CT0-A

10. CERN September 29, 200410W.H.Trzaska HIP Jyväskylä 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

11. CERN September 29, 200411W.H.Trzaska HIP Jyväskylä 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

12. CERN September 29, 200412W.H.Trzaska HIP Jyväskylä 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

13. CERN September 29, 200413W.H.Trzaska HIP Jyväskylä T0 electronics milestones 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) Shoebox Main electronics Main electronics

14. CERN September 29, 200414W.H.Trzaska HIP Jyväskylä 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

15. CERN September 29, 200415W.H.Trzaska HIP Jyväskylä T0 cost estimate: 318 kCHF

16. CERN September 29, 200416W.H.Trzaska HIP Jyväskylä Referee question: delay vs. HV 1.5 ps / V