The Silicon Detector Concept Taipei ACFA Meeting November 9, 2004 John Jaros

Taipei ACFA Jaros2 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 Jaros3 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 BR 2 for particle flow, improve momentum resolution for tracker, reduce backgrounds for VXD Use Si microstrips for precise tracking

Taipei ACFA Jaros4 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  M$) Cost [M$] Fix BR 2 =7.8, tradeoff B and R  Stored Energy [GJ] Delta M$ vs B, BR 2 =7.8 [Tm 2 ]

Taipei ACFA Jaros5 Result: SiD Design Starting Point B = 5T R ecal = 1.25m Z ecal = 1.74m

Taipei ACFA Jaros6 Critical Questions for Calorimetry Can this Si/W ECAL be built? What is the expected performance? Physics Performance vs BR 2 ? Is BR 2 = 7.8 right? R ecal = 1.25m; Z ecal = 1.67m; B=5T Is that really optimal? Ecal and VXD These and other subsystem design questions motivate the SiD Design Study

Taipei ACFA Jaros7 ECAL

Taipei ACFA Jaros8 Si Detector/ Readout Chip Readout ~1k pixels/detector with bump-bonded ASIC Power cycling – only passive cooling required Dynamic range OK ( mip) Pulse Height and Bunch Label buffered 4 deep to accommodate pulse train Engineering underway (U Oregon, BNL, SLAC)

Taipei ACFA Jaros9 HCAL Inside the coil R in = 1.42m; R out = 2.44m 4 Fe (or W, more compact) 2cm Fe, 1cm gap Highly segmented 1x1 cm 2 – 3x3 cm 2 ~ 40 samples in depth Technology? RPC Scint Tile GEM S. Magill (ANL) …many critical questions for the SiD Design Study: thickness? Segmentation? Material? Technology?

Taipei ACFA Jaros10 Silicon Tracking Why silicon microstrips? SiD starting point Robust against beam halo showers Thin, even for forward tracks. Won’t degrade ECAL Stable alignment and calibration. No wandering T to D. Excellent momentum resolution (  p/p 2 ~2 x )

Taipei ACFA Jaros11 But is pattern recognition robust? 5 Layer Pixel VXD fully efficient, even with backgrounds. N. Sinev, Victoria ALCPG 04  = 99.9% for p t >.18 GeV/c VXD vector + 5 axial layer barrel tracker fully efficient, even with backgrounds. S. Wagner, Paris LCWS04  > 98 %, more to come ECAL helps recognize K 0 ’s and  ’s or exotic particle decays mid-tracker. E. von Toerne, Victoria ALCPG 04  under study

Taipei ACFA Jaros12 VXD Tesla SiD Shorten barrel, add endcaps.  Shorten Barrel CCDs to 12.5 cm (vs. 25.0cm) supporting disk endcaps (multiple CCDs per disk)  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 Jaros13 ECAL Finds K 0 ’s von Toerne and Onoprienko (KSU) use track segments found in the ECAL, then extrapolate back to tracker Design Study Questions: K 0 efficiency? Impact on calorimetry? KS0 decay radius in XY plane (cm)

Taipei ACFA Jaros14 Moving beyond the starting point Options 1 & 2 B. Cooper, FNAL Support Si on C fiber/Rohrcell sandwich cylinders and disks (X=.002X 0 ) Whole assembly rolls out along beamline VXD/beampipe access Very forward tracking system mounted on beam pipe Stagger layers to avoid material overlap Pattern recognition questions remain Barrel: axial only? A + S ? Endcap: ~radial only? R + S? XUV?

Taipei ACFA Jaros15 Solenoid Specs: B = 5T; R in = 2.5m;  R =.85m; L = 5.4m Stored Energy = 1.1 GJ (!!!) Concept: Based on CMS 4T. Saclay team helping with conceptual design. B T /B < ? Field homogeneity not critical for SiD tracking. X-angle: Dipole compensation for crossing angle must be considered B r

Taipei ACFA Jaros16 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 Catcher B field homogeneity for forward ecal? Longitudinal segmentation? Technology? Very Forward Tracking Pixels or strips? Very Forward Cal (huge and active area!) Active masks and vetoes Lumcal Beamcal (pair monitor)

Taipei ACFA Jaros17 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 Jaros18 Come to the SiD re-launch Meeting! Today at 17:30 -19:00 here in R204 Everybody welcome! Individuals and R&D groups can participate in several design studies. Broad, interregional participation in the design studies is a necessity. Program Today Design Study Goals Harry Weerts SiD’s Critical Questions Jim Brau Computing/Simulation Norman Graf Discussion/Questions/ All Expressions of interest Interested? Sign up here: SiD web page: