Francesco Forti SuperB Workshop LNF, 16-18 March, 2006 Detector WG Francesco Forti SuperB Workshop LNF, 16-18 March, 2006

A SuperB Detector Basic conclusion from December Workshop: It is possible to reuse large parts of Babar and Belle with relatively minor technology changes Detector components Silicon vertex, with small radius pixels, essential for reduced boost. Drift chamber DIRC style PID, with improved readout CsI(Tl) calorimeter in barrel, something faster (LYSO) in endcap Existing coil LST style muon detectors March 17, 2006 F.Forti - Detector WB

Issue number 0 Beam parameters Current and Collision frequency vary wildly in different designs Was mA and 1MHz in december Raimondi – Round with extraction: 100 mA and 10 MHz Raimondi – Flat(3) uncompressed: 1600mA and 500 MHz Seeman – 4500 mA and 68 MHz Different options have very large impact on technology choices and on the reusability of Babar and Belle components. March 17, 2006 F.Forti - Detector WB

Collision frequency With 0.1-1MHz fc one could exploit the beam crossing time structure to relax detector constraints Drift time Electronics shaping time Crystal decay time One the other hand a low fc implies overlapping events (mainly Bhabha) The 10-50MHz regime is the LHC electronics area It might be possible to exploit the bx time structure, but is it useful ? At high fc (>100MHz) back to current BFactories operation mode Continuous beam, no bx information no pileup March 17, 2006 F.Forti - Detector WB

Current Two consequences of higher currents: higher background in the detector occupancy radiation damage power dissipation in the beampipe requires water cooling more material larger radius March 17, 2006 F.Forti - Detector WB

Types and level of backgrounds Beam gas Synchroton radiation  Both proportional to current Should not be a problem at Superb They become a problem at higher currents Luminosity sources (eg radiative Bhabhas) Careful IR design. Bhabhas into the detector are there. Beam-beam interactions Potentially important Touschek background 1/E2. Improves with smaller asymmetry. But, much higher beam density Thermal outgassing Due to HOM losses. Not an issue with small currents Injection background Not an issue because of damping rings scheme Maybe not true anymore with the 1 collision/turn scheme Bursts Due to dust. No real cure. Need robustness of detector March 17, 2006 F.Forti - Detector WB

Background bottom line Probably reasonable to assume background is not larger than what with have today Cannot claim a large background reduction with present schemes Need to design a robust detector with the enough segmentation and radiation hardness to withstand surprises (x5 safety margin) IR design is critical Radiative Bhabhas Syncrotron radiation shielding Shielding from beam-beam blow up March 17, 2006 F.Forti - Detector WB

Issue number 1 Boost lower boost advantegeous for machine design Babar: 9 + 3.1 βγ=0.56 Belle: 8 + 3.5 βγ=0.45 SuperB?: 7 + 4 βγ=0.28 we can afford to have a lower boost only if the vertexing resolution is good: small radius beam pipe very little material in b.p. and first layer if not, then we should stay with higher boost (0.45) March 17, 2006 F.Forti - Detector WB

Separation significance <Dz>/s(Dz) vs bg March 17, 2006 F.Forti - Detector WB

Detector components Vertexing Intermediate tracking Central tracking Thin pixel layer glued on beam pipe Good aspect ratio for small radius (compared to strips) Improves patter recognition robustness needs R&D Intermediate tracking Strip detectors More or less like the current detectors Reduction in thickness would be desirable, but not essential Central tracking Drift chamber Solid state tracking not performant at low momentum Need to optimize cell size against occupancy Belle has developed a fast gas small cell DCH, but with a degraded resolutions March 17, 2006 F.Forti - Detector WB

Detector components PID Calorimeter Muon Trigger/DAQ Čerenkov based PID – like DIRC Need development on readout Fast focusing DIRC TOP Endcap region requires special study Calorimeter Barrel part could be reused (see other talks) In the endcaps require smaller Moliere radius and faster crystals  LYSO Higher currents and smaller Bhabha pileup may change this conclusion Muon It doesn’t seem to be a problem Trigger/DAQ Calorimeter and/or tracking information Not substantially different from current schemes. March 17, 2006 F.Forti - Detector WB