SiD Tracker Concepts M. Breidenbach History Evolution 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach Design Drivers Excellent momentum measurement E-Flow calorimetry costs push towards modest(??!!) radius – nominally 1.25 m E-Flow and momentum measurement both push BR2 – nominally 5 T. Ergo want tracker with excellent φ measurement- Si Strip Detectors! Excellent multiparticle resolution Seems hard to beat Si Strips with ~50 μ pitch. Jets and backgrounds pretty dense. 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach More Design Drivers Robustness in a linear collider environment. “This (a linear collider) aint LEP!” John Jaros, circa early 2000’s. SLC/SLD experience indicates that Si leads directly to peaceful sleep at night. CCD’s were fine, wire and gas detectors were sensitive to beam blasts (that could not happen). Keep the detector thin. Experience indicates that endplates of barrel systems ruined forward tracking. (Even SLD!) Experience indicates that measured stuff (from multiple scattering) much greater than early drawings. Note that cable have to exit some place. We acknowledge that a profound physics case for thin in the LC context has probably not yet been made – so keep working at it! 6 February 2004 SiD Tracker Concepts M. Breidenbach

Tracker Layout Choice Un-simulated and Un-engineered 6 February 2004 SiD Tracker Concepts M. Breidenbach

Find tracks from Vertex Detector Find tracks from 5 layer CCD VXD. SLD was quite successful with 3 layers. Should extrapolate well into Tracker (Momenter?) Demo in progress – e.g. Steve Wagner. 6 February 2004 SiD Tracker Concepts M. Breidenbach

Make Structure of Long Ladders Readout half ladders from ends. Wire bond 10 cm square detectors in daisy chain as in GLAST. Minimal electronics and power pulsing make gas cooling easy. No liquids, leaks, or associated mass. 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach What's Wrong? We have no support to do anything, except maybe think a little bit. The outer barrel half length is (nominally) 17 detectors. This is a lot of capacitance. S/N is problematic. Timing tag is hopeless. Detectors thinner than ~300 μ ~hopeless. The detectors are wire bonded on a (almost) massless spaceframe. A wirebonding machine for this needs to be invented. 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach What else is wrong? Forward Disks are quite problematic: Occupancy too high. Mechanics of making long multi-detector trapezoidal segments ugly. Timing tag ~necessary. 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach Evolve Ditch (romantic) notion of long ladders and read out each detector. Detector has signals routed to rectangular grid for bump bonding to detector, analogous to design for Si-W Calorimeter. Strip Detector Bypass Caps Thin Kapton Cable Readout Chip 6 February 2004 SiD Tracker Concepts M. Breidenbach

Space Frame “Sketches” 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach Si-W Calorimeter 1024 channels of: Threshold Gain Sense VCal Cf Ccal Range Bit Cfl Ref Reset End of Conversion Convert Integrate Hold Discharge Current Source Reset (before train) Si-W Calorimeter Analog Section February 2004 6 February 2004 SiD Tracker Concepts M. Breidenbach

Proposed Tracker Electronics 2048 Channels of: Threshold VCal Cf Ccal Reset End of Conversion Convert Integrate Hold Discharge Current Source Reset (before train) SiD Tracker Analog Section February 2004 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach Advantages Higher modularity & improved occupancy Improved S/N Easy time tag No wire bonding Very modular assembly Possibility of thinner detectors. Stereo (even large angle) is easy. Most of these particularly advantageous for forward disks. 6 February 2004 SiD Tracker Concepts M. Breidenbach

SiD Tracker Concepts M. Breidenbach More Barrel is ~7000 detectors. @40 mW (average, probably generous) per ROC, total power is 280 watts. Endcaps should be less. OK for gas cooling? Put data concentrator on end of ladder, accept connector (!!) from detector cable. Concentrator output is on optical fiber. Cable is kapton w copper traces. 20 micron copper 3 mm wide seems ok for chip power; other traces narrower. 6 February 2004 SiD Tracker Concepts M. Breidenbach

Thickness Budget (Rough!) Material Thickness (Microns) Thickness Radiation Lengths (%) Silicon 300 0.32 Kapton 70 0.02 Copper 20 0.14 Carbon (Structural support) 500 (average) 0.27 Total 0.75 6 February 2004 SiD Tracker Concepts M. Breidenbach

(Tentative) Conclusions Simple is better Need to evaluate occupancy forward (and lots of other stuff) 6 February 2004 SiD Tracker Concepts M. Breidenbach