Oregon R&D for a Future Linear Collider

Oregon R&D for a Future Linear Collider Ray Frey DoE Review, Jan 6, 2004 • ALCPG leadership – Brau • Working group leaders: • New Physics - Strom • IPBI – Torrence • Vertex Detectors – Brau • Calorimetry - Frey • Context • Ongoing R&D • beam instrumentation • vertex detector • calorimeter M. Iwasaki DoE Review R. Frey

At the LC, the initial state is well defined… It has to be measured to be well defined ! • Luminosity and luminosity spectrum • Energy • Polarization

Oregon R&D on Energy measurement How this was done at SLC  At LC, precision driven by sharp thresholds (,resonances?) • e.g. top threshold m  100 MeV/c2 • Similar for SUSY states  E/E  few x 10-4

Oregon IPBI R&D: LC Energy Spectrometer Goals • Prepare module for End Station A beam test (ESA LoI) • Increase multi-PMT channels • Begin simulations of detector response • Combine with UMass beam simulations • Coordinate with worldwide efforts, cold and warm

At the LC, vertexing is (nearly) ideal • Tiny, stable interaction point • Small inner radius 1 cm • Clean events allow full reconstruction of secondary vertices  mass, charge, … • Beam duty cycle allows readout of slow pixels • Moderate radiation  Superior b,c (u,d) flavor tagging SLC/SLD success: CCDs the obvious default technology… • Thin • Industrialized • Main issue: radiation 100x worse than SLC (n,em)

Charge flushing shown to fill traps and ameliorate damage using spare VXD3 ladder. IEEE Trans. Nucl. Sci. 47, 1898 (2000) In 2003 VXD3 was disassembled for measurements. It was subjected to radiation from a beam accident in 1996 – was it due to neutrons or em radiation? Conclude that it was due to em radiation. Damage very similar to 1012 e/cm2 of 60 MeV energy electrons (NLCTA). Need to be aware of such events at LC.

Oregon vertex detector R&D status Near-term goals • physics simulations – detector thickness impact • continue radiation damage studies • mechanical engineering of support structure • study CMOS pixel option • conceptual design of readout • start detailed NLC/GLC design for CCDs

Dan Green, Calor2002 • LHC Study: Contributions to dijet mass resolution • Z -> JJ. dM/M ~ 13% without FSR. FSR is the biggest effect. The underlying event is the second largest error (if cone R ~ 0.7). Calorimeter resolution is a minor effect. • At the LC, the situation is reversed: Detection dominates. • Opportunity at the LC to significantly improve measurement of jets.

Physics: Jets! • Complementarity with LHC : • LC should strive to do well what • LHC finds problematic: • Measure ALL final states • Primary goal: Uncover the nature of electroweak symmetry breaking • e+e- → hZ → jets • e+e- → WW/ZZ (X)→ jets • Tau id. and pol. • Aid flavor id. (b/c) • Will get excellent results for e, mu, photons “for free” •  The “Particle Flow” paradigm →→+o DoE Review R. Frey

SLAC-Oregon Si-W ECal R&D • LC physics drives overall detector optimization • Multi-jet final states  “particle flow” • ECal which is dense and highly segmented (in 3-d) • “imaging” calorimeter: tau, photon, MIP, e, mu, hadron reconstruction • Expect >2x better jet-energy resolution than LEP (0.3/sqrt(Ejet) ) • Silicon-tungsten ECal is ideal realization • Our goal: How to make it practical while maintaining performance… • Highly integrated electronic readout (reduce cost and complexity) • Simple, robust silicon detector design (low cost) • Flexible design relative to eventual performance optimization • e.g. transverse segmentation nearly independent of cost • FY03 LCRD proposal was well received • Initial prototypes: • Pixels are 5 mm x 5 mm x 0.6 X0 • A detector element (wafer) is 800 pixels with one full readout chip • Readout includes 2000 dynamic range and timing at few ns level • Power off when no beams  simple, passive cooling

Wafer and readout chip DoE Review R. Frey

Oregon-SLAC Si-W Status • Technical tests of initial prototypes; ongoing simulations • Thermal, noise, resolution • Complete mechanical design of gaps (thickness!)  module • Construct a full-depth module: 15cm x 15cm x 30 X0 • Ready for test beam in 2005 • First prototype silicon detectors delivered Jan/04 • Electronics design converging for initial chip order early ‘04 • Tungsten for full prototype in hand – 1m pieces ok

Effective Moliere radius • Standard SD: 5x5 mm2 pixels with (1) 0.4mm or (2) 2.5mm readout gaps. • 10 GeV photons; look at layer 10 Looks like <1 mm readout gap is possible DoE Review R. Frey

Calorimeter R&D Overview • ALCPG Calor. WG: Active group – telecons every other week; fill up 4 2-hour parallel session agendas every 6 months; organized 2 sim. workshops (3rd in June). • Detector R&D making good progress – “on track” • Simulation effort needs to move forward – validate PFlow  detector optimization DoE Review R. Frey

Oregon R&D for a Future Linear Collider