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Stato del progetto RICH di LHCb

Stato del progetto RICH di LHCb. CSN1 Lecce, 24 settembre 2003. LHCb RICH detectors. Particle ID over 1 – 100 GeV/c provided by 2 RICH detectors. RICH2: No major changes since RICH TDR. PRR in february 2003 Superstructure ordered The first 10 mirrors accepted

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Stato del progetto RICH di LHCb

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  1. Stato del progetto RICH di LHCb CSN1 Lecce, 24 settembre 2003 CSN1, Lecce 24/9/2003

  2. LHCb RICH detectors Particle ID over 1 – 100 GeV/c provided by 2 RICH detectors RICH2: No major changes since RICH TDR PRR in february 2003 Superstructure ordered The first 10 mirrors accepted Exit window being assembled RICH1: major design changes included in new TDR Motivated by : the requirements for improved L1 trigger (0.15 Tm in tracking region) Reduce material in the spectrometer acceptance CSN1, Lecce 24/9/2003

  3. Rich-2 exit window CSN1, Lecce 24/9/2003

  4. Rich-2 exit window CSN1, Lecce 24/9/2003

  5. Impegni italiani nel RICH-2 Genova : supporti fotorivelatori Milano: schermo magnetico consegna al CERN ottobre 2004 ottica (test, allineamento) CSN1, Lecce 24/9/2003

  6. RICH-1 Reoptimization Reduced material within spectrometer acceptance: • Light spherical mirrors • Mirror supports outside acceptance • RICH-1 entrance window removed, sealed directly to the VELO tank 14% radiation length in TDR design < 8% B field for L1: • Shielding of photon detectors 600  25 G CSN1, Lecce 24/9/2003

  7. RICH-1: Material Budget Item % X0 % lI Entrance window 0.0 0.0 Aerogel 3.3 0.7 C4F10 2.6 1.6 Spherical mirror 0.8 0.7 Exit window 0.6 0.3 Total 7.3% 14% in TDR design 3.3% 5% in TDR design CSN1, Lecce 24/9/2003

  8. The vertical RICH-1 CSN1, Lecce 24/9/2003

  9. The vertical RICH-1 The optics CSN1, Lecce 24/9/2003

  10. The radiators of RICH-1 • Gas system (85 cm) • C4F10no more available commercially • mix C3F8 and C5F12 • (increase cost) 2. Aerogel (5 cm) milestone LHCC in september 2003 CSN1, Lecce 24/9/2003

  11. Aerogel radiator : the final detector A LHCC milestone (september 2003) Parameters n=1.030 (± 0.0002) thickness 5 cm (tolerance 4 mm) in 1 layer or 2.5+2.5 cm clarity C< 0.0065 mm-4 (<0.0050) transversal dimensions : 80x60 cm Container very light box (carbon fiber entrance + 0.1 mm D263 exit window) 2 parts splitting vertically 0.2 + 3.3 + 0.08 about 3.5 % X0 total weight ~ 4 Kg Integration in RICH1 structure to be finalized (supported by the superstructure) within the drawings of Imperial College CSN1, Lecce 24/9/2003

  12. Aerogel radiator : the final detector A LHCC milestone (september 2003) The tiles will be produced in Novosibirsk (from June to December 2004) tested (in parallel) and mounted in 2004-2005 in Milano detector ready as sealed boxes in June 2005 CSN1, Lecce 24/9/2003

  13. RICH-1 Mirrors • Spherical mirrors • 82 cm x 60 cm, R=240 cm: 1 per quadrant • 2 technologies under study (decision by end 2003) • Carbon fibre: 2 mm thick • ¼-scale prototype satisfies optical quality • Stability in fluorocarbon gas undergoing tests • Beryllium: 3 mm thick, with 0.3 mm glass coating • ¼-scale prototpye satisfies optical quality • Compatible with flurocarbon gas • Higher cost than carbon fibre • Secondary plane mirrors (outside acceptance) • 37 cm x 39 cm: 4 per quadrant • Glass: 6 mm thick CSN1, Lecce 24/9/2003

  14. RICH-1: Performance Number of photoelectron hits per ring Cherenkov angle precision Number of photon hits per trigger In BB event Contributions to Cherenkov angle precision CSN1, Lecce 24/9/2003

  15. Photodetector Technology choice Pixel HPD: LHCb development (+DEP,VTT) 83 mm diameter hybrid photodiode array Silicon pixel sensor, bump-bonded to 40MHz readout chip encapsulated in vacuum tube Effective pixel size: 2.5mm x 2.5 mm 2 technologies considered: MaPMT: Hamamatsu M64 multianode PMT Coupled to BEETLE r/o electronics (similar to LHCbSi trackers) 1760 tubes required in RICH-1 Quartz lens on each MaPMT to increase active area (48%) Less stringent reduction of field (25 gauss instead of < 10 Gauss) Magnification x 1.5 and effective pixel size is 3mm x 3mm Switch to MaPMT baseline in June 2003 Final Decision for october 2003 CSN1, Lecce 24/9/2003

  16. Status of HPDs Bump-bonding problem SOLVED 8 new assemblies delivered end of may tested with Sr90, baked out and re-tested No bump-bonding degradation 2 assemblies mounted at DEP in two 40 MHz HPDs tubes and delivered 5/8/03 No bump-bonding degradation,chip operation OK, tubes operated at 20 kVNO PROBLEM CSN1, Lecce 24/9/2003

  17. Status of HPDs • VTT informed on 20.5.2003 about the presence of a crust on the bumps’ top prior to flip-chip assembly. This most probably explains why the above assemblies were not optimal. The crust problem is understood and solved. After before CSN1, Lecce 24/9/2003

  18. Status of HPDs first of the two 40 MHz HPDs tubes installed in T9 (PS beam) on 19/8/03 Cerenkov rings were recorded the same day Both tubes successfully tested on the beam preliminary laboratory tests, ageing tests also OK (detection efficiency 87%) CSN1, Lecce 24/9/2003

  19. Cherenkov air rings • CO2 counter @ 2.0bar CSN1, Lecce 24/9/2003

  20. Rings diameters • 2D histogram sliced at weighted center • Gaussian fits to the y axis histograms • Internal ring and external ring diameters on sensor are determined • Int diam= 9.28 mm • Ext diam= 7.52 mm CSN1, Lecce 24/9/2003

  21. 40MHz HPD: preliminary lab. tests • LED measurements started (50ns strobe), back-pulse visibility • decreased (larger detector!, ie larger capacitance) • Detection efficiency (first estimate): ~87% • (includes correction for long (250ns) back-pulse shaping time, LED tail (4%) and non- working pixels (2%)) CSN1, Lecce 24/9/2003

  22. mounting holes for mount to vessel grounding points 5x boardBeetle with Beetle 1.2 8-dynode stage MaPMT slits to access potentiometers Cambridge bleeder board mounting holes for lens mount base plate for mounting and grounding Status of MaPMT Cluster Setup HV point rotation of 4 bleeder chains CSN1, Lecce 24/9/2003

  23. First Spectra with boardBeetle before CM correction after CM correction Beetle 1.2: 800V =1.02 Beetle 1.2MA0: 800V =0.55 Beetle 1.2: 800V =0.77 Beetle 1.2MA0: 800V =0.51 Beetle 1.2: 900V =0.78 Beetle 1.2: 900V =1.06 Beetle 1.2MA0: 900V =0.55 Beetle 1.2MA0: 900V =0.53 Saturation at half the dynamic range: present before the FED! CSN1, Lecce 24/9/2003

  24. First Cherenkov Light • 8 MaPMTs • no lenses • HV = 800 V • Cherenkov Ring • Air 960 mbar • 3.6 pixels / event with 5 sigma cut • from raw data CSN1, Lecce 24/9/2003

  25. Cherenkov Rings • Cherenkov photons, CF4 800mbar: 8-stage MaPMT, Beetle1.2; with lenses, -900V from raw data with cross-talk cut on left or right neighbour 10.3 photons/evt 6.5 photons/evt beam: -10 GeV  mostly - CSN1, Lecce 24/9/2003 Test will go on in october

  26. RICH project costs (kCHF) CSN1, Lecce 24/9/2003

  27. Sharing of RICH cost After reoptimization Before reoptimization CERN 1016 ITALY 1000 UK 5674 9566 Total cost 7690 CSN1, Lecce 24/9/2003

  28. PROVISIONAL CSN1, Lecce 24/9/2003

  29. PROVISIONAL CSN1, Lecce 24/9/2003

  30. Spare slides CSN1, Lecce 24/9/2003

  31. The LHCb Detector Reduced number of layers for M1 (4  2) Reduced number of tracking stations behind the magnet (4  3) No tracking chambers in the magnet No B filed shielding plate Full Si stationReoptimized RICH-1 design Reduced number of VELO stations (25  21) Changes were made for material reduction andL1 trigger improvement CSN1, Lecce 24/9/2003

  32. VELO • 19 stations needed to cover the LHCb acceptance ( > 3 stations / track)+ 2 stations for robustness = 21 stations Track loss for 2521= 0.1%, 2120 = 0.5% CSN1, Lecce 24/9/2003

  33. Prototype work advancing Al window CSN1, Lecce 24/9/2003 EDR planned for June 2004

  34. Cost of the experiment cf. MoU VELO 4.82 IT 2.47 TT 3.40 OT 6.23 RICH 9.57 Calo 15.06 Muon detect. 6.93 Muon Fe 4.00 L0 Trig 2.26 DAQ&CPU farm 5.71 ECS&TFC 1.58 Computing infra. 0.71 Experiment infra. 4.00 Magnet 6.00 MoU included VETO -0.28 +0.72 Now all Si TT*) -3.86 10  3 stations*) +1.87 New RICH1*)&MaPMT analogue cost -0.30 -0.52 +0.06 With VETO *) due to reoptimization Increase of RICH1 mechanics from TDR = 492kCHF:  B field shielding box, Be mirror, superstructure, etc. CSN1, Lecce 24/9/2003 Total cost = 72.74 MCHF (-2.31 MCHF from the MoU cost)

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