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The Silicon Detector Concept. Taipei ACFA Meeting November 9, 2004 John Jaros. Calorimetry drives the Detector Design.
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The Silicon Detector Concept Taipei ACFA Meeting November 9, 2004 John Jaros
Calorimetry drives the Detector Design W’s, Z’s, top, H’s,… are the quanta we must identify, and missing energy is the critical signature. All depend on calorimetry. Need to measure jet four-momenta well enough to identify and discrimminate W’s, Z’s, top, H’s,… Need ~4 acceptance for good efficiency with multi-jet final states SiD starting assumptions…particle flow calorimetry will deliver the best possible performance Si/W is the right technology for the ECAL Taipei ACFA Jaros
The SiD Rationale Premises: Excellent physics performance, constrained costs Si/W calorimetry for excellent jet resolution therefore… • Limit Si/W calorimeter radius and length, to constrain cost • Boost the B field to recover BR2 for particle flow, improve momentum resolution for tracker, reduce backgrounds for VXD • Use Si microstrips for precise tracking Taipei ACFA Jaros
Cost (and physics) balance R and B High Field Solenoid and Si/W Ecal are major cost drivers. Magnet Costs Stored Energy (SiD ~1.1GJ 80-100 M$) Cost [M$] Fix BR2=7.8, tradeoff B and R Stored Energy [GJ] Delta M$ vs B, BR2=7.8 [Tm2] Taipei ACFA Jaros
Result: SiD Design Starting PointB = 5T Recal = 1.25m Zecal = 1.74m Taipei ACFA Jaros
Critical Questions for Calorimetry • Can this Si/W ECAL be built? • What is the expected performance? • Physics Performance vs BR2?Is BR2 = 7.8 right? • Recal = 1.25m; Zecal = 1.67m; B=5T Is that really optimal? Ecal and VXD These and other subsystem design questions motivate the SiD Design Study Taipei ACFA Jaros
ECAL Taipei ACFA Jaros
Si Detector/ Readout Chip Readout ~1k pixels/detectorwith bump-bonded ASIC Power cycling – only passive cooling required Dynamic range OK(0.1 - 2500 mip) Pulse Height and Bunch Label buffered 4 deep to accommodate pulse trainEngineering underway(U Oregon, BNL, SLAC) Taipei ACFA Jaros
HCAL • Inside the coil • Rin= 1.42m; Rout= 2.44m • 4 Fe (or W, more compact)2cm Fe, 1cm gap • Highly segmented1x1 cm2 – 3x3 cm2~ 40 samples in depth • Technology?RPCScint TileGEM S. Magill (ANL)…many critical questions for the SiD Design Study: thickness? Segmentation? Material? Technology? Taipei ACFA Jaros
Silicon Tracking Why silicon microstrips? SiD starting point Robust against beam halo showers Thin, even for forward tracks. Won’t degrade ECALStable alignment and calibration. No wandering T to D. Excellent momentum resolution (p/p2~2 x 10-5) Taipei ACFA Jaros
But is pattern recognition robust? 5 Layer Pixel VXD fully efficient, even with backgrounds. N. Sinev, Victoria ALCPG 04 = 99.9% for pt > .18 GeV/cVXD vector + 5 axial layer barrel tracker fully efficient, even with backgrounds. S. Wagner, Paris LCWS04 > 98 %, more to comeECAL helps recognize K0’s and ’s or exotic particle decays mid-tracker. E. von Toerne, Victoria ALCPG 04 under study Taipei ACFA Jaros
VXD Tesla SiD Shorten barrel, add endcaps. Shorten Barrel CCDs to 12.5cm (vs. 25.0cm) add 300 m Si self-supporting disk endcaps (multiple CCDs per disk) This extends 5 layer tracking over max , improves forward pattern recognition. improve Coverage, improve impact param 5 CCD layers .97 (vs. .90 TDR VXD) 4 CCD layers .98 (vs. .93 TDR VXD) Readout speed and EMI are big questions. Taipei ACFA Jaros
ECAL Finds K0’s von Toerne and Onoprienko (KSU) use track segments found in the ECAL, then extrapolate back to tracker Design Study Questions: K0 efficiency? Impact on calorimetry? KS0 decay radius in XY plane (cm) Taipei ACFA Jaros
Moving beyond the starting point Options 1 & 2B. Cooper, FNAL Support Si on C fiber/Rohrcell sandwich cylinders and disks (X=.002X0) Whole assembly rolls out along beamlineVXD/beampipe access Very forward tracking systemmounted on beam pipe Stagger layers to avoid materialoverlap Pattern recognition questions remainBarrel: axial only? A + S ?Endcap: ~radial only? R + S? XUV? Taipei ACFA Jaros
Solenoid Specs: B = 5T; Rin = 2.5m; R = .85m; L = 5.4m Stored Energy = 1.1 GJ (!!!) Concept: Based on CMS 4T. Saclay team helping with conceptual design. BT/B < ? Field homogeneity not critical for SiD tracking. X-angle: Dipole compensation for crossing angle must be considered Br Taipei ACFA Jaros
SiD Subsystems So far, we’ve concentrated on calorimetry, tracking, and magnet, since they define SiD architecture. Other subsystems need development & integration. • Flux Return/Muons/Had Tail CatcherB field homogeneity for forward ecal?Longitudinal segmentation?Technology? • Very Forward TrackingPixels or strips? • Very Forward Cal (huge and active area!)Active masks and vetoesLumcalBeamcal (pair monitor) Taipei ACFA Jaros
SiD Design Study The SiD concept is being developed in a Design Study.“Blessed” by WWS OC“Launched” by Harry Weerts and John Jaros (still looking for that bottle of champagne…)“Announced” at Victoria ALCPG, Durham ECFA, and now Taipei ACFA. We are looking for colleagues in all regions to transform the SiD starting point into a real design. The study needs the full range of HEP expertise:physics analysis, detector simulation, pattern recognition/particle flow code development, detector R&D, mechanical design. Our goals: conceptual design, demonstrated physics performance, defined R&D path, cost estimate. Taipei ACFA Jaros
Come to the SiD re-launch Meeting! • Today at 17:30 -19:00 here in R204 • Everybody welcome! Individuals and R&D groupscan participate in several design studies. • Broad, interregional participation in the design studies is a necessity. • Program TodayDesign Study Goals Harry Weerts SiD’s Critical Questions Jim Brau Computing/Simulation Norman Graf Discussion/Questions/ All Expressions of interestInterested? Sign up here:SiD web page:http://www-sid.slac.stanford.edu Taipei ACFA Jaros