Detector R&D towards the Technical Design Report

1. Detector R&D towards the Technical Design Report DRD2TDR Francesco Forti University and INFN, Pisa SuperB International Review Laboratori Nazionali di Frascati November 12-13, 2007

2. Scope • We have a SuperB detector concept based on Babar • Still, a significant amount of work is needed to turn this concept into a full detector design and write a Technical Design Report in about 2 years: • Physics studies to optimize overall detector geometry • Background studies to optimize Machine-Detector-Interface design, detector space-time granularity and verify radiation levels • Detector subsystem physics-engineering studies to produce a sound subsystem design • Technology development for some specific subsystem components to improve performance • For each subsystem this talk will try to report where we stand in this process and present the plans for the future • Including some indication of who’s doing the work F.Forti - DRD2TDR

3. Outline • Computing • Backgrounds • Silicon Vertex Tracker • Drift Chamber • Particle Identification Detector • Electromagnetic Calorimeter • Instrumented Flux Return • Trigger, DAQ, Electronics • Manpower F.Forti - DRD2TDR

4. Computing • Computing “in” the TDR will be based on Babar+LHC experience: solvable problem • Fully detailed Computing TDR may come even a bit later than the detector TDR • Computing “for” the TDR is instead essential from now to the TDR • Collaborative tools • Web, Code and document repository, Wiki, mailing lists, etc. • Simulation tools • Physics studies, Background simulation, Detector studies • Mostly used Babar-derived tools so far, but a more flexible and varied simulation infrastructure will be needed Bologna, Ferrara, Padova, Pisa, Torino, SLAC F.Forti - DRD2TDR

5. Simulation tools used • Beamline and backgrounds • MAD: established FORTRAN code for beamline sim. • BDSIM: Geant4-based beamline sim. • G4-based magnet and detector sim. to track particles in detector volume • Geometry initially hardcoded. • Started using GDML = Geometry Description Markup Language • SuperB Detector and Physics • Generator level studies • Full G4 Babar simulation with minor geometry changes • Babar/Pravda/Trackerr fast simulations: • replace Babar tracker with simple conical-cylindrical detector • realistic fit with material, but no pattern recognition • Subsystem specific code • What next: • Develop a fast simulation tool based on Babar existing code, but allowing easy change of detector geometry and performance • Integrate with background simulation • Benefit from ILC developments F.Forti - DRD2TDR

6. Background • Sources (a re-evaluation is needed for TDR) • Beam-gas: ok because of low current • SR fan: can be shielded (see IR talk) • Touschek: delicate, see next slides • QED cross section Frascati, Pisa, SLAC F.Forti - DRD2TDR

7. Background sources • Radiative Bhabhas • Beamline and shielding design are paramount • Showering and backscattering extends to large radius Rate 100kHz/cm2 @ R=1.2 cm • Pair production • Low Pt make magnetic shielding effective • Issue for first layer of SVT • Rate 15MHz/cm2 @ 1.2cm 5MHz/cm2 @ 1.5cm Pt accept. @ 1.5 T , 1.2 cm ~Angular acceptance F.Forti - DRD2TDR

8. Touschek Background • Intrabeam scattering produces Touschek particles all along the ring, depending on emittance and bunch volume • Beam optics and collimator setting essential in controlling this background • Two-step simulation: • estimate primary Touschek particles hitting the B.P. in the I.R. with dedicated code • track the particles in the detector volume with G4 simulation • New lattice and collimators VERY effective • Not an issue anymore • Need to be carefully verified with final design F.Forti - DRD2TDR

9. Silicon Vertex Tracker • The Babar SVT technology is adequate for R > 3cm: use design similar to Babar SVT • Layer0 is subject to large backround and needs to be extremely thin: > 5MHz/cm2, 1MRad/yr, < 0.5%X0 • Striplets option: mature technology, not so robust against background. • Marginal with background rate higher than ~ 5 MHz/cm2 • Moderate R&D needed on module interconnection/mechanics/FE chip (FSSR2) • CMOS MAPS option • new & challenging technology: • can provide the required thickness • existing devices are too slow • Extensive R&D ongoing on 3-well devices 50x50um2 • Hybrid Pixel Option: tends to be too thick. • An example: Alice hybrid pixel module ~ 1% X0 • Possible material reduction with the latest technology improvements • Viable option, although marginal F.Forti - DRD2TDR

10. 50x50 um2 pixels 90Sr/Y electrons 3x3 Cluster signal Landau MPV: 700 e- Noise ENC = 50 e- S/N = 14 Noise mV MAPS R&D Extensive R&D ongoing (and needed): • Fast readout architecture • Digital to analog xtalk • Architecture scalability (4k64K) • Pixel cell optimization • Increase S/N (1530) • reduce power dissipation x2 • Radiation hardness • Not fully qualified yet. Irradiation program • Mechanical issues • sensor thinning, module design, low mass cooling • Test Beam foreseen in Sep 2008 • Prototype MAPS module + striplets SLIM5 Collaboration F.Forti - DRD2TDR

11. Radius, thickness, resolution • MAPS low mass solution would leave more flexibility for radius (ie background) and resolution • Hybrid pixels will force to use the smallest radius and/or better resolution • Striplets (same MAPS material) require larger radius, performance marginal • Technological solutions depend critically on L0 radius, thickness, resolution • Fast simulation studies for variousdecays have been performed • A full, more detailed reassessment is needed for the TDR. Dt resolution in Bpp decays vs L0 X0(%) 10mm resolution 5mm resolution BaBar • beam pipe material: 0.4% X0 • b. p. inner R 1cm, o.r. 1.1 cm • layer0 radii = 1.2, 1.5, 1.7 cm • material for L0 = [0.2-1.5] % X0 • hit resolution = [5-15] mm MAPS MAPS F.Forti - DRD2TDR

12. Bergamo, Bologna, Milano, Pavia, Pisa, Torino, Trieste SVT Activities • Strong Ongoing R&D • MAPS sensor chip development • Fast readout architecture • Pixel cell optimization • Radiation hardness • Mechanical issues • sensor thinning, module design, low mass cooling • striplets module • Simulation studies ongoing • Strongly connected with machine design and backgrounds simulation • Optimize detector geometry and granularity • Explore alternative technological solution • Test Beam foreseen in Sep 2008 (and probably 2009) • Prototype MAPS module + striplets F.Forti - DRD2TDR

13. Technology adequate, but 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 Possibility of fast waveform sampling electronics for cluster counting Conical, Carbon fiber endplate Further optimization of cell size/gas Activities Complete background simulation Test different gas mixtures on small DCH prototype Use the Frascati Beam Test Facility (e+/e- up to 500 MeV) Drift Chamber Frascati, SLAC F.Forti - DRD2TDR

14. Particle Identification Detector • DIRC Barrel • Working very well. Main limitation from background generated in SOB and aging of PMTs • Readout Options • SOB: Faster PMTs using the standoff box and water coupling • Smaller SOB: Multi Anode PMTs and fused silica coupling • No SOB: Focusing readout with Multi Anode PMTs F.Forti - DRD2TDR

15. Focusing DIRC Projected performance Concept Focusing readout for DIRC very promising. R&D ongoing on the mirror and photon detector Tests on possible photondetectors F.Forti - DRD2TDR

16. Forward/Backward PID option • Extending PID coverage to the forward and backward regions has been considered • Possibly useful, although the 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 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 already achieved. 10ps seems to be achievable, although not easy F.Forti - DRD2TDR

17. PID activities Cincinnati, Hawaii, Ljubljana, Novosibirsk,Padova, SLAC • R&D activity ongoing on many items • Photon detectors (MCP, PMTs, SiPM): uniformity, fast timing, cross talk, aging • Beam test of long bar focusing DIRC correcting chromaticity effects • Low power, fast timing electronics • Radiators: aerogel, NaF • Plan to produce realistic prototypes • Test beams desired, but precise plans still in preparation • Possibility of parasitic SLAC beam test in 2008 • Other possibilities being explored • Simulation studies to fully assess the benefits of the forward PID F.Forti - DRD2TDR

18. 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 • 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 • Use as a VETO device for rare channels such as Btn. • Physics impact needs to be quantitatively assessed • DIRC bars are necessarily in the middle • DCH electronics relocation is critical for the perfomance • Could be made with lead/scintillator fiber technology such as KLOE F.Forti - DRD2TDR

19. 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 • Leaves PID option open • CsI option still open • in case of cost/availability issues F.Forti - DRD2TDR

20. EMC Test beam preparation • LYSO Test beam foreseenin 2009 • Test crystal response • Mechanical support andeffect of dead material F.Forti - DRD2TDR

21. EMC Activities Caltech, Perugia, Roma • R&D ongoing on many items: • Crystals • uniformity, yield, performance characterization, radiation hardness • work with multiple vendors to improve price and performance • Readout: • opimize photon detector, design robust mechanical mount • Beam Test • develop mechanical support, data acquisition • define beam location and time • Simulation ongoing to: • Detector layout optimization (geometry, dead material, mechanical support, etc.) • Assess physics case for backward calorimeter • Testbeam foreseen in 2009 for 5x5 LYSO array F.Forti - DRD2TDR

22. Instrumented Flux Return • Use scintillator bars à la MINOS • FNAL-NICADD (produced the MINOS bars) contacted • Already provided some spares for R&D purposes • Technology established, but optimization is needed • Readout type: F.Forti - DRD2TDR

23. Fibers and readout F.Forti - DRD2TDR

24. IFR Activities Ferrara, Padova, Roma1 • Ongoing R&D Activities and studies: • SCINTILLATOR: • Shape, Number of fibers, time response, coating • WLS FIBERS: • diameter, dopant concentration, shape, response speed • Photodetectors: APD vs. geiger mode devices • cost effectiveness, S/N, time resolution, gain stability vs voltage and temperature, channell uniformity, aging • Readout electronics • ADC-TDC electronics (used for DIRC) vs Constant Fraction Discrimination-TDC • Plans for full system test • Detection efficiency, Time/space resolution • 2008 lab test with sources/cosmic rays • Beam test of a prototype module foreseen in 2009 • Simulation studies • Optimization of the detector layout (dimension of scintillator slabs, number of layers, ...) F.Forti - DRD2TDR

25. Electronics and Trigger/DAQ • Electronics and TDAQ based on Babar model • Areas of R&D / Studies • Per-channel requirements and channel counts • Detector occupancy estimates • Level-1 trigger tracking improvements • Bhabha veto at L1 • Study of target L1-accept capacity (100kHz vs. 150kHz if not Bhabha veto) • Virtually dead-time-free DAQ, overlapping events and/or triggers • Queue modeling of the system • Applicability of a BaBar-physics-filter-type filter in SuperB L3 • Applicability of alternative approaches (such as the ones used in LHC experiments) • Clearly a major cost driver • Several interested individuals, but core group not yet formed • Significant engineering will be needed to arrive at TDR F.Forti - DRD2TDR

26. Manpower • We are in the process of detailing the manpower needs to arrive at the TDR • Physicists, engineers, technicians • We estimate that a group of about 75 physicsts and about 30 engineers, technicians, and computing professionals would be required over the next 2 years to prepare the TDR • The SuperB community is large and active and should be able to take on this task: already about 30 physicists and 10 engineers are actively involved in detector R&D • More groups are joining and will join the effort if the project is approved • Some key roles, such as chief mechanical and eletrical engineer might require specific hiring F.Forti - DRD2TDR

27. Conclusions and outlook • We have a very sound detector concept • The R&D required to arrive at a technical design report is well defined and in most systems has already started • This R&D can be completed in 2 years • There are backup solutions for technical and cost risks • It is possible to build a detector that will deliver the SuperB physics F.Forti - DRD2TDR

28. BACKUP SLIDES

29. Pair Background vs. Radius F.Forti - DRD2TDR

30. 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 - DRD2TDR

31. Detector Layout F.Forti - DRD2TDR