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D3: Vertex Vertex Detectors Detectors for the Linear Collider

Jim Brau Univ. of Oregon

LCWS 2000 Fermilab October 28, 2000

J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Physics Opportunities of the Linear Collider
· Premier physics goals of linear collider characterized by heavyquark decays and small cross sections ­ eg. Higgs branching ratios tt (usually 6 jets, 2 b) tth (usually 8 jets, 4 b jets) AH (12 jets with 4 b jets) and other reactions
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Requirements of the Vertex Detector
· Highly efficient and pure b and c tagging, including tertiary vertices (bc) · Charge tagging (eg. b/b discrimination) · These goals are achieved by optimized impact parameter performance:
­ ­ ­ ­ point resolution < 4 µm detector thickness < 0.2% X inner radius < 2 - 3 cm good central tracker linking
0

· Also must take care with timing and radiation hardness
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

SLD has demonstrated the power of a PIXEL detector in the LC environment
· 307,000,000 pixels · 3.8 µm point resolution · pure and efficient flavor tagging at the Z-pole
­ ~ 60% b eff with 98% purity ­ > 20% c eff with ~ 60% purity

· We need a pixel solution
­ decision on option can wait ­ optimize options based on active R&D program
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Options under development
· CCDs
­ system level demonstration with SLD (307,000,000 pixels) ­ R&D to advance performance

· Hybrid Active Pixels (HAPDs)
­ fast, rad-hard

· Monolithic APDs
­ fast, rad-hard

We need to pursue all of these options vigorously to ensure the best possible vertex detection at the LC
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Session D3
· CCDs
­ C. Damerell (system development) ­ K. Stefanov (mech./ rad-hard devel.)

· Hybrid APDs
­ M. Caccia (prototype, charge sharing) ­ G. Alimonti ("3-D" detectors, bmp bnd)

· Monolithic APDs
­ G. Deptuch (prototype, beam test)

· Performance studies
­ ­ ­ ­ ­ ­ T. J. S. B. M. A. Abe (heavy jet tagging) Brau (Higgs BRs) Xella (flavor tagging) Schumm (aggressive scenarios) Battaglia (3 Tev - CLIC) Miyamoto (flavor tagging)
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Charge Coupled Devices (CCDs)
· Chris Damerell
­ system development
· build on SLD experience with years of operation with 307,000,000 pixels

­ 5 barrel, 799,000,000 pixels with beampipe radius of 14 mm and 3 hit coverage to cos = 0.96 ­ thinning ladders to 0.06% X0 ­ Readout architecture
· column-parallel readout for TESLA

· Konstantine Stefanov
­ investigating near Troom use ­ mechanical design studies ­ rad-hard devel. to reduce CTI
· improves 60-100 times · "will survive 10 years"
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Hybrid APDs (Active Pixel Devices)
· Massimo Caccia
­ readout pitch > pixel pitch ­ prototype tested ­ charge sharing efficiency demonstrated ­ next step beam test of improved device

· Gianluca Alimonti
­ first "3-D" detectors fabricated
· leakage currents 1/4-1 nA/mm3 (Troom) · low depletion voltage · active edges

­ Rad-hard XTEST2 ­ bump bond yields good ­ next year prototype system
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Monolithic APDs (CMOS)
· G. Deptuch
­ prototype tested with beam
· 64 x 64 pixel arrays

­ next year increase size
· ~ 10 cm

­ outstanding potential
· · · · rad-hard high precision ultra thin low cost

­ issues to address
· expand to system · power

J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Performance studies
· Bruce Schumm
­ aggressive scenarios (just to see)
· · · · improved resolution ( 1 µm) smaller beampipe ( 0.5 cm) greater radial extent ( 11 cm) thinner layers (and pipe) ( 0.06% X0)

­ conclusions:

· good central tracking vital · spatial resolution and beampipe radius lead to substantial improvements

· Akiya Miyamoto
­ flavor tagging ­ conclusion:
· significant improvement with inner radius of 1.2 cm vs. 2.4 cm

J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Performance studies
(continued)
· Toshi Abe
­ heavy jet tagging ­ ZVTOP installed into LCD simulation

· Stefania Xella
­ flavor tagging with neural net including ZVTOP ­ update for new TESLA geometry ­ future ZVTOP3, vertex charge, dipole charge

· Jim Brau
­ detector parameters and Higgs BRs

J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Performance studies
(continued)

· Marco Battaglia
­ 3 Tev - CLIC ­ extreme energies lead to some very long decay lengths (several cm) ­ proposes counting tracks with pulse height information ­ demonstrates viability with simulation of (e+ e- b b) determination

J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Summary of LCWS2000
· Progress continues to advance on many fronts ­ CCDs · R&D to advance the already demonstrated exceptional system-level performance ­ Hybrid APDs · prototypes with charge sharing understood · "3-D" detectors fabricated ­ Monolithic APDs · effort to capitalize on industry standards · first chip shows extraordinary promise ­ Performance simulations · tradeoffs becoming clearer
J. Brau, LCWS 2000, October 28, 2000


D3: Vertex Detectors

Future Directions
· Continue progress on all fronts
· CCDs · Hybrid APDs · Monolithic APDs

· Performance simulations
· Refine our understanding of the impact of detector trade-offs on physics performance

· We will be able to exploit the exceptional physics opportunities of the LC
J. Brau, LCWS 2000, October 28, 2000