The Detector F.Forti, INFN and University, Pisa Pisa, 5 maggio 2007

F.Forti - SuperB Project2 May 5, 2007 Outline Detector requirements and considerations The SuperB Baseline Detector  SVT  DCH  PID  EMC  IFR  Trigger/DAQ  Computing Budget and Schedule

F.Forti - SuperB Project3 May 5, 2007 Experimental considerations Babar and Belle designs have proven to be very effective for B-Factory physics  Follow the same ideas for SuperB detector  Try to reuse same components as much as possible Shifted physics emphasis  Rare decays   physics  Decays involving ’s. Additional emphasis on:  Angular coverage Improve reconstruction  Resolution&efficiency Tracking & vertexing Energy resolution Particle ID Muon ID Often more relevant for background rejection than for signal reconstruction

F.Forti - SuperB Project4 May 5, 2007 SuperB Detector Main issues  Machine backgrounds Higher than and different from PEP-II/KEKB  Beam energy asymmetry Smaller: 7+4 GeV   =0.28  Strong interaction with machine design Of course, as in Babar and Belle Impact on  Detector segmentation  Radius of beam pipe and first sensitive layer  Radiation hardness Aging  Several components are not reusable because of aging, even if the design would be ~OK.

F.Forti - SuperB Project5 May 5, 2007 Detector Layout – Reuse parts of Babar (or Belle) BASELINE OPTION

F.Forti - SuperB Project6 May 5, 2007 SuperB Layout with dimensions

F.Forti - SuperB Project7 May 5, 2007 Backgrounds More details in Gianni’s talk Dominated by QED cross section  Low currents / high luminosity Beam-gas are not a problem SR fan can be shielded

F.Forti - SuperB Project8 May 5, 2007 Pair production Huge cross section (7.3 mbarn) Produced particles have low energy and loop in the magnetic field Most particles are outside the detector acceptance

F.Forti - SuperB Project9 May 5, 2007 Need serious amount of shielding to prevent the produced shower from reaching the detector. We have an IR design coping with main BKG source Radiative BhaBha

F.Forti - SuperB Project10 May 5, 2007 Backgrounds SuperB beam currents (2A) are similar to PEP- II/KEKB Background is not too much larger than what with have today  Except for SVT Layer0  Detailed simulations ongoing, especially for radiative Bhabhas and Touschek backgrounds  Need to design a robust detector with the enough segmentation and radiation hardness to withstand surprises (x5 safety margin) IR design is critical Shielding More studies needed

F.Forti - SuperB Project11 May 5, 2007 Beam Pipe Radius and Detector Separation significance Proper time difference resolution 7+4GeV Boost  =.28 Instead of 0.56 Small beam pipe radius possible because of small beam size  Studied impact of boost on vertex separation (B   )  Rest of tracking is Babar  Beam pipe needs to be cooled.Study is in progress to keep total thickness low in the order of % of  rad

F.Forti - SuperB Project12 May 5, 2007 Beam pipe 1.0 cm inner radius Be inner wall  ≈ 4um inside Au coating 8 water cooled channels (0.3mm thick)  Power ≈ 1kW Peek outer wall Outer radius ≈ 1.2cm Thermal simulation shows max T ≈ 55°C Issues  Connection to rest of b.p.  Be corrosion Outer wall may be required to be thermally conductive to cool pixels

F.Forti - SuperB Project13 May 5, 2007 SVT Baseline: use an SVT similar to the Babar one, complemented by one or two inner layers.  Question on whether it would possible/economical to add a layer between SVT and DCH, or move L5 to larger radius Cannot reuse because of radiation damage Beam pipe radius is paramount  inner radius: 1.0cm,  layer0 radius: 1.2cm,  thickness: 0.5% X0 40 cm 30 cm 20 cm Layer0

F.Forti - SuperB Project14 May 5, 2007 SVT Layer 0 Depends critically on background level  Striplet solution (baseline) Basically already available technology but more sensitive to background. OK for 1MHz/cm 2 Some margin to improve background sensitivity  Monolithic Active Pixel Solution solution (option) R&D is still ongoing but giving a big safety margin in terms of performance and occupancy Cooling and mechanical issues need to be addressed See talks in the afternoon V U 1.35 cm 7.7 cm

F.Forti - SuperB Project15 May 5, 2007 Striplets detector concept

F.Forti - SuperB Project16 May 5, 2007 DCH Basic technology adequate. Cannot reuse BaBar DCH because of aging  Faster gas and smaller cell would be beneficial Baseline:  Same gas, same cell shape Some gas improvement possible (order 20%) Reducing cell dimension deteriorates resolution  Carbon fiber endplates instead of Al to reduce thickness  Backgrounds simulated, dominated by radiative Bhabhas Depend critically on shielding About 7% occupancy with current solution, could be reduced to 1.5% Options/Issues to be studied:  Miniaturization and relocation of readout electronics Critical for backward calorimetric coverage  Conical, Carbon fiber endplate  Further optimization of cell size/gas

F.Forti - SuperB Project17 May 5, 2007 DCH Gas and Cell Size

F.Forti - SuperB Project18 May 5, 2007 Particle ID Barrel PID essential for hadron PID above ~0.7GeV. DIRC baseline  Quartz bars are OK and can be reused Almost irreplaceable  PMTs are aging and need to be replaced  Keep mechanical support Barrel Options  Readout options motivated by reduction of background generated in SOB  SOB: Faster PMTs using the standoff box and water coupling  Smaller SOB: Pixilated MaPMTs and fused silica coupling  No SOB: Focusing readout with pixilated MaPMTs

F.Forti - SuperB Project19 May 5, 2007 Forward/Backward PID option Extending PID coverage to the forward and backward considered Possibly useful, physics case needs to be established quantitatively Serious interference with other systems  Material in front of the EMC  Needs space cause displacement of front face of EMC require miniaturization and displacement of DCH electronics  TOF seems the only viable option Technologies Aerogel-based focusing RICH  Working device  Requires significant space (>25 cm) Time of flight  Need about 10ps resolution to be competitive with focusing RICH  15-20ps OK. 10ps seems to be achievable, although not easy

F.Forti - SuperB Project20 May 5, 2007 EMC Barrel CsI(Tl) crystals  Still OK and can be reused (the most expensive detector in BaBar)  Baseline is to transport barrel as one device Various other transportation options  Background simulation indicates the need for a careful shielding design dominated by radiative Bhabha’s Forward Endcap EMC  BaBar crystal are damaged by radiation and need to be replaced  Occupancy at low angle makes CsI(Tl) too slow  No doubt we need a forward calorimeter Backward EMC option  Because of material in front will have a degraded performance Maybe just a VETO device for rare channels such as B  .  Physics impact needs to be quantitatively assessed  DIRC bars are necessarily in the middle  DCH electronics relocation is critical for the perfomance

F.Forti - SuperB Project21 May 5, 2007 EMC Backgrounds Integrated over  120 crystals in the barrel, 100 in the forward Limit for CsI(Tl) at about 1MeV/us/crystal More detailed studies and optimization are needed

F.Forti - SuperB Project22 May 5, 2007 Forward EMC crystals Both pure CsI and LSO could be used in the forward EMC LSO more expensive, but more light, more compact, and more radiation hard  Now LSO is available industrially  Cost difference still significant, but not overwhelming. Use LSO as baseline  Gives better performance  Mechanically easier to assemble  Leaves PID option open CsI option still open  in case of cost/availability issues

F.Forti - SuperB Project23 May 5, 2007 Crystal properties

F.Forti - SuperB Project24 May 5, 2007 IFR and steel BaBar configuration has too little iron for  ID  > 6.5 I required; 4-5 available in barrel Fine segmentation overdid K L efficiency optimization  Focus on  ID : fewer layers and more iron   Is it possible to use the IFR in K L veto mode ? Baseline:  Fill gaps in Babar IFR with more iron  Leave 7-8 detection layers  Need to verify structural issues  Scintillator bars à la MINOS Cost effectiveness of steel reuse needs to be fully assessed

F.Forti - SuperB Project25 May 5, 2007 IFR Backgrounds Rates in the range of a few x 100Hz/cm2

F.Forti - SuperB Project26 May 5, 2007 Electronics and Trigger/DAQ L1 Trigger rate of KHz  Unless a hardware Bhabha rejector is developed  Up from 5KHz current Babar rate Some electronics could be reusable  Especially front-end cards, maybe power supplies The bulk of the electronics is obsolete and unmaintainable  Should be remade with state-of-the- art technology Clearly a major cost driver  Costed using recent experiments experience (LHC)

F.Forti - SuperB Project27 May 5, 2007 Computing Computing model extrapolated from Babar  Scales with luminosity Requires distributed computing on the grid

F.Forti - SuperB Project28 May 5, 2007 Cost estimate A full cost estimate of the SuperB project has been done  Based on Babar/PEP-II actual costs  Escalated from 1995 to 2007  Bottom-up for almost all elements Separate new components from reused elements  Replacement value of reused components = how much would it cost today to rebuild those components (extrapolated from Babar/PEP-II costs)  New costs: everything that’s needed today, including refurbishing  Transport is not included, but disassembly and reassembly is. Keep separate categories:  EDIA: engineering, design, inspection and administration (man- months)  Labour: technicians (man-months)  Materials and Services: 2007 Euros. All details available in the CDR  We have not tried to fully optimize the cost yet. Some reduction might be possible

F.Forti - SuperB Project29 May 5, 2007 Detector cost Note: options in italics are not summed. We chose to sum the options we considered most likely/necessary.

F.Forti - SuperB Project30 May 5, 2007 Computing costs Computing depends critically on the time scale  Moore’s law Evaluated in two scenarios:  startup in 2011 or 2012 Not included in basic detector budget  LHC model:  distributed computing resources  provided by many partners The on-site computing center is included in the estimates  should probably called out as a separate entity

F.Forti - SuperB Project31 May 5, 2007 Schedule Overall schedule dominated by:  Site construction  PEP-II/Babar disassembly, transport, and reassembly We consider possible to reach the commissioning phase after 5 years from T0.

F.Forti - SuperB Project32 May 5, 2007 The Università di Roma Tor Vergata Site Area available Strong interest of University and INFN Tunnel at about -12m Synergy with approved FEL (SPARX) Engineering group created Issues: water, power 750m

F.Forti - SuperB Project33 May 5, 2007 Summary and outlook A SuperB detector based on Babar has been developed  It could be based on Belle as well Technology is available  Some areas require focused R&D to be finalized (see David’s talk)  Final technology choices will need to be made Main goals for the workshop  Understand the needed R&D effort  Create some structure to move forward Longer term  Arrive to a Technical Design Report in 1-2 years

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F.Forti - SuperB Project35 May 5, 2007 Accelerator and site costs Note: site cost estimate not as detailed as other estimates.