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

The Silicon Detector Concept

Taipei ACFA Meeting

November 9, 2004

John Jaros

Taipei ACFA Jaros 2

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 3

The SiD RationalePremises: 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 4

Cost (and physics) balance R and BHigh 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]

Cost Partial, Fixed BR^2

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Taipei ACFA Jaros 5

Result: SiD Design Starting PointB = 5T Recal = 1.25m Zecal = 1.74m

Taipei ACFA Jaros 6

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 7

ECAL

Taipei ACFA Jaros 8

Si Detector/ Readout ChipReadout ~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 train

Engineering underway(U Oregon, BNL, SLAC)

Taipei ACFA Jaros 9

HCAL• Inside the coil• Rin= 1.42m; Rout= 2.44m• 4 Fe (or W, more compact)

2cm Fe, 1cm gap• Highly segmented

1x1 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 10

Silicon TrackingWhy 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/p2~2 x 10-5)


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


VXD Tesla SiD

Shorten barrel, add endcaps. Shorten Barrel CCDs to 12.5 cm (vs. 25.0cm)

add 300 m Si self-supporting disk endcapssupporting disk endcaps (multiple CCDs per disk) (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.

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ECAL Finds K0’svon 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)


Moving beyond the starting pointOptions 1 & 2 B. 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?


SolenoidSpecs: 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


SiD SubsystemsSo 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 TrackingPixels or strips?

• Very Forward Cal (huge and active area!)Active masks and vetoesLumcalBeamcal (pair monitor)


SiD Design StudyThe 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.


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: http://www-sid.slac.stanford.edu

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

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