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DCH: What We Know DCH: What We Want The BABAR DCH worked well for almost 10 years • A lighter structure, all in Carbon Fiber (CF) • because we know this can be done • investigate possible options • A faster detector, with faster R.O. electronics • because we know life will be tougher @ SuperB • Simulations, R&D studies with prototypes • Lighter FEE (including shielding & cooling) • because we may want to place detectors behind the DCH backward endplate now
Spherical Carbon-Fiber end-plates PRELIMINARY! Minimize thickness at fixed deformation Thickness O(4mm), or 0.015 X0 compare 0.13 X0 in BABAR Concave Convex shape could fit better e.g. with forward PID device Convex
A possible occupancy issue High background rates expected in the forward region • to be quantified with detailed simulations • high occupancy in innermost cell layers, possibly tamed with: • tapered endplates • screening the sense wire • discussed in next slides
plastic collar sense wire 80 mm inner Ø, 120 mm outer Ø ~10cm long peek tube “good physics track” 30 mm W (Au-plated) wire ionization in very forward region Screening the sense wire • Prevent electron multiplication in selected regions along sense wire • To test the idea: we built drift tubes, with part of the sense wire ‘screened’.
No source Free wire Further down the plastic tube Start of plastic tube End plug “B” End plug “A” Scan the wire with a 90Srsource:Current vs. source position • Preliminary tests indicate that screening the sense wire works as expected • e.g. current drops to half the value when 90Srsource exactly placed beginning of screen • Next step is measuring charge and time-to-distance with MIPs. • Need also to consider carefully: • Long-term behavior/aging (Modify the wire diameter instead?) • Stringing issues
Re-commissioning of DCH prototype Started re-commissioning of small DCH prototype Wires OK Electronics OK Gas tightness OK Read out few channels Signals look good Need more electronics to read out all underway Can easily replace bolted end plates with new ones with different cell geometries Re-commissioning of precision tracker • First pass with coarse space-time relations achieved resolution of 120mm • on-board electronics for all 52 channels being designed, to be ready after Summer 30-May-2008 Elba Super-B Workshop 7
Summary and Outlook Evaluating different solutions with an all-Carbon-Fiber structure Perform test of wire screening with MIP’s Completing set up of all necessary tools for our R&D plan Proceed with Garfield simulations of various cell geometries to select few solutions to test Build new prototype’s end plates with different cell geometry solutions Prepare for test beam
PID R&D- USA Whether there is, or is NOT, a forward PID system depends on there being a clear, strong physics case. If there is such a case, the technology chosen for a forward PID system depends on # physics requirements on which momentum region is most useful; # photo-detector choice; # engineering issues; # background resistance; # cost. Adequate backward PID may be obtained by a fast backward EMC instead of a separate detector. This option should be carefully explored Ongoing R & D includes work on Photon detectors, fast timing, and Aerogel radiators Even without the EC PID devices, major effort is required to design and construct the new SOB and DIRC photon detection system. New groups/individuals interested in PID design and R&D are strongly encouraged to join the effort. See JJV talk
counts Distance ~200 cm sigma 1.8 ns Distance ~200 cm sigma 1.3 ns MPPC SiPM 1.5 p.e. Cut pedestal 2 p.e. 1 p.e. adc channels ADC spectrum for MPPC IFR: R&D status Present baseline configuration: Scintillator:1.5cm thick with embedded hole /surface groove Fiber:One Saint-Gobain BCF92 1.0 mm diameter Readout: Geiger mode APDs from Hamamatsu or IRST-FBK Average number of p.e.:~ 9 at maximum distance (~4m) Efficiency better that 95% Detailed study of SiPM and MPPC signal characteristics: a lot has been done, still more to do The time resolution is < 2 ns and is better with SiPM (IRST) than with MPPC (Hamamatsu)
Simulation • A first description of the IFR is ready for Geant4 simulation. • First events have been generated and analyzed for consistency checks. • Further validation will be done with more statistics. Need full reconstruction to obtain a fine detector optimization. The plan is to use the BaBar framework + SuperB background events. Fast simulation: plan to release a preliminary version useful for physics by the end of June Then improve the parameterization according to the detector optimization.
SuperB IFR path to TDR For the TDR: • Simulation requested detector performance • Detector Design • Scintillator • Fiber • Photodetector: time resolution, afterpulses, noise, radiation hardness • Electronics + DAQ • Preliminary Detector Layout, including preliminary mechanics/detector integration (Summer09) • Prototype Design Construction (starting Sept09) • Prototype Beam Test (Spring 2010) • Final Layout for TDR (Summer/Fall 2010) At present:Ferrara, Padova, Roma1 Institutions A lot of work to be done for TDR,additional forces very helpful and welcome!
Computing Developments since Elba Summer! Formation of the computing planning group - Gregory Dubois-Felsman (chair) - David Brown - Peter Elmer - Fabrizio Bianchi - Roberto Stroili - Mauro Morandin (ex-officio) Still need contributions from detector community Status report at R&D meeting tomorrow
Summary of BaBar Reuse, Transport,& SuperB Home-Bill • BaBar Disassembly starts soon; lasts ~4 years. • Components for re-use in SuperB, namely the EMC Barrel, DIRC bar boxes and support structure, and coil and cryostat with support systems, are removed from the barrel steel for move to SuperB in mid-2010. • EMC Barrel transfer Tor Vergata: hope to ship as a unit, preferably by air. Engineering is needed to determine if this is feasible. If not, disassembly of the barrel down to 280 modules (each typically 21 crystals) and support cylinder structures will add considerable time until the installation of the EMC Barrel into SuperB. Additional environmentally conditioned assembly space would be required in the disassembly case. • DIRC transport as a single structure is not practical: structures are too big and require vertical transport due to bar box construction. It is best if bar boxes are removed and shipped separately. • Magnet cryostat has been shipped from Ansaldo to SLAC by air, providing proof of principle for return to Italy. • Steel will arrive somewhat later, by boat, after the sextants are separated from each other and split in two.
BaBar Reuse, Transport, SuperB Home Site of SuperB hall will provide a spacious home, properly sized from experience at IR2, for these systems. Coexistence with the embedded accelerator final focus cryostats promises to be challenging.
Summary • We are beginning to develop beyond our conceptual design (as presented in the SuperB CDR) for the SuperB detector, based on BaBar. • Substantial Planning, Design, and Physics and Detector simulation studies are needed to continue the process.The individual Subsystems need R&D and appropriate software tools to develop the best detector components within this overall design. • Impressive progress on software and simulation tools • We hope to move to a high quality technical design and TDR within ~ 2 years. • All areas need more people. Many opportunities exist to get (even more?) involved in the detector, including subsystem R&D and general detector systems, software, physics simulation, and design. 22