regina demina, hadron collider workshop, fnal, october 16-18, 20031 slhc tracking issues regina...

Regina Demina, Hadron collider workshop, FNAL, October 16-18, 2003 1

SLHC tracking issuesSLHC tracking issues

Regina Demina, University of Rochester

International Workshop on Future Hadron Colliders:Physics, Detectors, Machines


OutlineOutline

• Accelerator upgrade stages• Requirements on tracking• Radiation hard R&D• Electronics issues• System integration issues• Summary

• AI=action item (to be addressed in future workshops)


LHC upgrade stagesLHC upgrade stages

• LHC performance:• 7 TeV beam• Beam-beam tune spread 0.01• 1.1 E11 p/bunch• L= 1E34 cm-1 s-1

• Phase 0: max performance w/o hardware changes to the LHC• Increase B to 9 T E to 7.54 TeV• Increase bunch intensity to 1.7E11p/bunch L=2.3E34

• O. Brüning et al., “LHC Luminosity and Energy Upgrade: a Feasibility Report”, LHC Project Report


LHC upgrade stagesLHC upgrade stages

• Phase 1: max performance while keeping the LHC arcs• * = 0.5 0.25 m• Crossing angle 300 rad425 rad (essential at decreased b* to

minimize long range collisions)• Bunch intensity at 1.7 E11 L =3.3 E34 cm-2 s-1

• Bunch crossing interval 25 12.5 ns• Increased intensity and other modifications L=4.7 E34 cm-2 s-1

• Phase 2: max performance with major hardware changes to LHC• Modify injectors• Superconduct magnets for SPS (injection E1TeV)• Mech and dynamic aperture changes x2 in L • L= 1.0 E35 cm-2 s-1 by 2015• New superconducting dipoles E14 TeV (a lot more R&D is

needed) – not considered in this discussion


Tracking in SuperLHCTracking in SuperLHC1. Radiation damage1. Radiation damage

• Design luminosity =10xLHC• Running time = ½ LHC (5 years)• Radiation dose = 5xLHC• Inner layers of SiTrk (r=20cm) are expected

to be operated at bias voltage 600V after 10 years of LHC

• SuperLHC 3kV (?!)1. Need replacement2. Need improved more rad hard technology3. The goal is to maintain tracking and b-

tagging performance


Tracking in SuperLHC Tracking in SuperLHC 2. Granularity2. Granularity

With collider energy and/or luminosity increase the emphasis shifts towards higher energy jets.

Energetic jets are more collimated need higher granularity

A.I. Local occupancy is more critical. Need to understand for typical jet E for objects at the threshold of sensitivity (e.g. use 7th heavy quark MQ production model)

ADCStrips

R=20 cm

7% of tracks in 500 GeV jets have merged hits

2.5% of tracks in 100 GeV jets


Possible detector configurationPossible detector configuration

• What to replace?• Most likely 100% of the tracking system

• Lifetime (no relation to radiation damage) of Si systems so far <~3-4 years, LHC=8-10 years

• Increase granularity• Electronics compatibility• To fix all the problems that are not known now

• Scaling law radiation 1/r2

• R<20 cm – new technology • 20<R<60 cm – pixels• R>60 – microstrips (with some technology pushing)


Directions in Tracking R&DDirections in Tracking R&D

• Use of defect engineering silicon• E.g. DOFZ is now used for ATLAS pixels, possibility for

CMS• 3D and new biasing schemes• New sensor materials

• Significant success with CVD diamonds• Cryogenic Silicon Tracker development

• Lazarus effect – x10 increase in rad hardness• Monolithic pixel detectors

• Sensor+readout on the same silicon substrate (no bump bonding)


Why now?Why now?

• CMS SiTrk detectors design time line• RD2 report – 1994• CMS technical proposal - 1994• RD20 report - 1995• RD48 report – 1997• Start construction phase 2003• Start data taking 2007 = 1994+13years

• SuperLHC start data taking 2015• RD?? report 2015-13=2001

• RD50 is formed 10/02 to address the needs of Super LHC


RD50RD50

• Approved by CERN 06/2002• 52 institutions, 5 from US (Fermilab, Purdue,

Rutgers, Syracuse, BNL)• Areas of research

• Material engineering• Oxygenation, si carbite

• Device engineering• Pad, 3D, thin detectors

• Rad hard technologies used for LHC are not completely characterized


RD50RD50


Radiation damage – microscopic Radiation damage – microscopic defectsdefects


Radiation damageRadiation damage

leakage currents at T=20C

1

10

100

1000

10000

100000

1E+09 1E+10 1E+11 1E+12 1E+13 1E+14 1E+15

10 MeV proton fluence 1/cm2

I_le

ak (

A/c

m3 ) HPK-L1-11

HPK-L1-12HPK-L2-059HPK-L2-62testdiodesROSE data

depletion voltage

050

100150200250300350400450500

1.0E+10 2.0E+13 4.0E+13 6.0E+13 8.0E+13 1.0E+14

10 MeV p fluence (1/cm2)

U_d

ep (V

)

HPK-L1-11HPK-L1-12Hamburg modelHPK-L2-059HPK-L2-062

Leakage current grows with rad doseP-type impurities concentration increases, sensor goes through np type inversion and then depletion voltage grows indefinitelyAnnealingReverse annealing


Oxygen enriched siliconOxygen enriched silicon

DOFZ (Diffusion Oxygenated Float Zone) O: 1016-1017 cm-3

• Introduced to HEP in 1999• Slows down V depl growth after type inversion

Reverse annealing delayed and saturated at high fluences


Device Engineering: 3D detectorsDevice Engineering: 3D detectors

Electrodes:Narrow columns along detector thickness 3DDiameter ~10 m, distance 50-100 mLower VdeplThicker detector possibleFast signal


CVD diamondsCVD diamonds

•Good progress lately Main issues charge collection distance reached 250 um •S/N = 8/1•Very radiation hard•Resolution improves (!) after 2E15 p/cm-2

•Pretty


Electronics issuesElectronics issues

•0.25 um 0.13 um• 0.25 um might not be

available on SLHC time scale or even worse only few vendors will be left

• 0.13 um – more rad hard

•Tracker in L1 trigger•Binary? – ATLAS experience will tell•Power supplies (why do they always become an issue)

•AI’s:•Cost of 0.13 um development is very high

• must managed cooperatively

•Power consumption at 80 MHz•Signal level

• At ~1V every welder in your neighborhood is your signal


System integration issuesSystem integration issues

•Large complex systems cannot be treated just as the sum of the parts•Installed in experiment detector systems exhibit features not present in laboratory testing•Commissioning is becoming a lengthy process 1-1.5 years•Why we are never able to get to b-tagging efficiency seen in Monte Carlo?


Examples of “integration issues”Examples of “integration issues”

•SuSy will jump at you after 2-3 weeks of LHC data taking

• Not the first two weeksSusy?No, calorimeter noise

•Silicon tracker (WSMT) calorimeter “cross talk”•Welders

DØ


Examples of “integration issues”Examples of “integration issues”

•CDF L00 – signal carried by analogue cables •Readout the whole L00•Fit pedestals with Chebyshev polynomials

•Another interesting story• Resonance Lorentz force

wirebond breaks


AI on integrationAI on integration

•A lot of experience gained by Tevatron • on integration and commissioning of large detector systems• Statistics of failure modes (e.g. 12% of a system lot due to poor

cable connection)• grounding

• Documentation• System integration is a worthy R&D project


SummarySummary

• LHC upgrades will deliver x10 in L and possibly x2 in energy

• Most likely entire tracking systems of both high Pt experiments will have to be replaced

• Requirements to tracking upgrades• Radiation hardness• Higher granularity• Fast response

• R&D program has started:• RD50 – silicon detectors• RD42 – good progress with CVD diamonds

• Electronics: 0.25 0.13 um transition • System integration must be given high priority


Action ItemsAction Items

• Understand local occupancy for typical jet E for objects at the threshold of sensitivity (e.g. use 7th heavy quark MQ production model)

• Electronics: • Cost of 0.13 um submissions • Power consumption• Signal and noise levels

• Integration• Documentation of Tevatron experience• R&D task

regina demina, hadron collider workshop, fnal, october 16-18, 20031 slhc tracking issues regina...

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