Tracking Challenges at Future Hadron Colliders Micro-Pattern Gas and Silicon Detectors for Tracking Jose E. Garcia Université de Genève 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions

Super LHC 2 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Next generation of Trackers comes with SLHC. Same machine but a whole new environment. LHC - Conditions in Phase 2 Increase luminosity by a factor of 10 BX of 50ns or 25 ns Pile-up can be up to 400 events per crossing SLHC parameters 20 interactions / BX interactions / BX 403

Super LHC 3 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Current CMS/ATLAS detectors are designed to withstand 300 fb -1. SLHC will accumulate around 3000 fb -1. ATLAS and CMS will need new trackers Completely new technology needed to withstand the radiation level (increased by up to 10 times). New layouts to fulfill the new requirements: – Occupancies – Material effects – Track reconstruction performance No physics reason yet identified to improve spatial and momentum measurement precision Goal maintain tracking and vertexing performance

Fermilab 4 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking CDF DØ b-layer and outer sensors work fine - even beyond design Single and double sided strip sensors Electronics has adequate high rate performance Chips SVX3 Cooling Water cooled Tracker is included in trigger SVT Sensors working fine even beyond design Single and double sided strip sensors Electronics Chips SVX-IIe Chips SVX4 (recent upgrade) b-layer installed (recent upgrade) Including tracker on trigger (recent upgrade) Operational faced issues: Wire bond resonances SEU on crates Blocked cooling lines Coolant degradation Operational faced issues: Limited trigger rate SVXIIe non expected “features” Grassy noise on sensors DVDD wire bond failures

LHC 5 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking ATLAS ID CMS Tracker Current CMS/ATLAS detectors are being commissioned. No hard tests for electronics and/or sensor resistance yet performed. Checks done on beam-tests and during installation/commissioning. Most of the issues so far related with infrastructures - to be solved during the shutdown: Cooling systems needed training. Compressors, heaters,… need to be repaired for normal operation Cabling. Huge amount of cables requires a large effort to properly map the system

SLHC (phase I) 6 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking The closest future comes with LHC Phase I in Expected 2xLHC luminosity Both experiments will need the innermost layer to be replaced. The problem has been addressed and work started. CMS is evaluating several scenarios is quite soon a simple upgrade planned: compatible with existing services & infrastructure no change in module count, number or radii of the layers minimal disturbance to physics output could include a material reduction by cooling improvement take advantage of barrel mechanics constructed for quick insertion or deinstallation ATLAS created the b-layer task force. Some of the conclusions are: B-Layer cannot be replaced in a 8 months long shutdown Other options as a simpler 2 hit system with present technology (case of disaster) not realizable (collaboration to make, spares not available) Recommended solution: inserted b-layer with new (module) technology. Studies and solutions should be defined soon (end of 2009 – begin 2010). Material budget is critical for this solution. Innermost layer(s) replacement will be a good test bench and a first step for future tracker technologies. S.Koenig

Sensors specs 7 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Innermost layer(s)  High radiation level needs  thinner layers - reduce depletion voltage  Decrease cooling temperature and/or use diamond/gas - reduce radiation damage Intermediate and Outer layers  Radiation is less an issue  Long pixels, short strips an option in this range. Different layouts studied A whole silicon pixel system will give a good performance (occupancy, pattern recognition,…) drawbacks: powering, material budget increase, costs,…

Sensors Layout 8 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Layout for a new tracker (example straw-man) ATLAS Radiation Taskforce Mix of neutrons, protons, pions depending on radius Long and short strips - damage largely due to neutrons Pixels - damage due to neutrons and pions Design fluences for sensors (include 2x safety factor) Fluence (n eq /cm 2 )Technology Innermost Pixel Layer1× D, Diamond, thin-Si, Gas,… Outer Pixel Layers3*×10 15 n + – p pixels Short strips1×10 15 n + – p Long strips4×10 14 present p + – n or n + – p

Technologies (short) 9 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking 3D silicon Harshest radiation environment for innermost layer (R~4 cm) – need new technologies 3D silicon Uses MEMS (Micro Electro Mechanical Systems) technology to engineer structures. Both electrode types are processed inside the detector bulk instead of being implanted on the wafer's surface Electric field between electrodes - shorter signal collection distances compared with planar devices: Lower depletion voltage (and therefore power) Faster and more efficient charge collection. CVD Diamond Tested at small scale applications (eg beam conditions monitoring) Large band gap and strong atomic bonds give excellent radiation hardness Low leakage current and capacitance = low noise Large band gap means ~2 less signal than Si for same X 0 Gas GOSSIP (micromegas) low mass and could get to good radiation resistance. See H. Van der Graaf talk Large scale production? Timescale? Cost ?

Readout at SLHC 10 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Occupancy increases: o more channels are needed to decrease the occupancy o maximum trigger rate for a fixed bandwidth decreases (event size increases) Higher number of channels o Increase of the number of ASICs o Increase of power needed  Front-End has to be improved Effective reduction of trigger rate  Needed a reduction of data transferred  Implementation of tracking at Level 1 ~400 interactions / BX (50 ns) CMS

Front-End 11 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking 0.13 µm technology would allow bigger chips, smaller pixels and higher output speeds. Goals driving the new FE chip design: material reduction and module live fraction increase. power reduction Requirements: SEU (Single Event Upset) protection and radiation hardness are crucial. Implementation of an on-chip shunt regulation to allow any powering scheme (Serial or DC-DC) Desirable: store all the information as long as possible locally

Trigger at SLHC 12 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking o The trigger will have to deal with the higher occupancies and data rates u Single µ and e L1 trigger rates will exceed 100kHz u Increase thresholds on electrons, photons, muons, jets and use of less inclusive triggers. u There may not be enough rejection power using the muon and calorimeter triggers to handle the higher luminosity conditions at SLHC u Need to compensate for larger interaction rate & degradation in algorithm performance due to occupancy u Adding tracking information at Level 1 gives the ability to adjust P T thresholds Level 1 trigger has no discrimination for p T  30GeV/c CMS

Tracker readout 13 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Number of hits in tracking devices on each trigger is enormous. Data reduction (or selective readout) essential, some options: Perform simple clustering on chip (send cluster center) Reduce number of bits per hit … Need of faster decisions. No time to transfer all data o ff -detector. Decision logic could be fast on-detector Combine tracker information to form tracks. Problems: The hit density means high combinatorial background Trigger functions must not degrade tracking performance

Track Trigger 14 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking High momentum tracks are straighter so pixels line up Pairs of stacked layers can give a P T measurement Geometrical p T - cut Topic requiring substantial R&D Compare pattern of hits in contiguous sensor elements in closely spaced layers Stub angle defines p T cut “Stacked” layers which can measure p T of track segments locally FTK (LVL1.5) Complete pattern recognition on the fly  hit data from silicon tracker is compared to a pattern bank with all possible hit patterns CDF 32k patterns per phi sector two orders of magnitude less than in SLHC experiments J. Jones et al (CMS) M. Shochet et al (ATLAS) off-detector on-detector

Infrastructure 15 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Important part of a tracking system contributing in a large share of the material budget. - Power and power cables - Reduce supplied voltage - Use DC-DC converters or Serial powering to reduce material - Cooling - CO 2 cooling, other cooling schemes - Structures and cables (slow control) - not in this talk - Most of present services (cables, fibers and cooling tubes) will have to be re-used. The least appealing part of a detector development (not many R&Ds are used to improve this). A perfect tracker will not work without cooling, power… If something can fail it will and there is a lot to fail in here

Infrastructure : Power 16 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Some of the challenges for an upgraded system: – High cable density, not much space left for cables – Heat load of cables must be removed – Cable voltage drops exceed ASIC supply voltages Serial DC - DC Minimize current through cables by: Serial Powering or DC - DC conversion Reducing the current to be fed by a factor of 5-to-10 minimum is reachable with both solutions DC-DC converters offer some interesting flexibility – Can separate different supplies easily Analog - digital saving in overall power Serial powering – Several options under study Both options open

Infrastructure : Cooling 17 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking  Avoiding thermal runaway becomes a big challenge for SLHC with its larger, higher granularity silicon system.  CO 2 cooling is widely perceived as a better alternative to the current C x F X cooling systems and already chosen as baseline for strip detector upgrade. High efficiency heat transfer with smaller pipes for reduced material.  Also a more environment friendly solution. H. Kästli 1g of -25ºC ~280 J (Where for C3F8 it is 100 J/g)

Infrastructure : Cooling 18 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking Allows long cooling loops (~2-3m) with very small diameter pipes (~1mm) for thermal loads of ~100 W CO 2 allows serialized pipes without pressure drop problems and therefore reduces resident cooling liquid by large factor. Density of liquid CO 2 is ~ 1.03 g/cm 3 compared to 1.76 g/cm 3 of C 6 F 14 and 1.35 g/cm 3 of C 3 F 8 Needs considerable engineering support from CERN. Cooling plant must withstand larger pressure (up to 100 bar). C 6 F 14 cooling CO 2 cooling Material budget for 3 barrel layers H. Kästli

Material Budget 19 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking ILC target material budget is ~0.1% X 0 per layer CMS In very central region ~0.4 X 0. Support structure has a large contribution Large amount of material from cables in forward region. Paths to reduce material: – Support : thermal Conductive Carbon foams: very low density, acceptable thermal performance. – Cooling : lower (than C X F X ) temperature coolant (CO 2 ): -35º, smaller pipes, lower fluid mass. – Sensitive : thinner layers. – Cables : services sharing between different modules/staves. SP or DC-DC powering – Electronics : Integration with sensors (3D architecture) and use of 0.13  m technology

Outlook 20 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking M. Weber

Conclusions 21 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking -Super LHC will arrive gradually starting Detectors will have to be ready before Phase II in A factor 10 on luminosity increase will be a big challenge for the detectors in the LHC tunnel - Increase of occupancy and radiation damage imposes requirements on the tracking systems. New tracking systems will have to be built. - A large list of problems will have to be addressed: - Radiation hard detectors - Reduce the occupancy by increasing channel number - Introduce tracking information at LVL1 - Reduce material budget - Reuse of existing services

and beyond… 22 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking

More… 23 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions 7.More Info Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking

More… 24 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions 7.More Info Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking P. Dervan

More… 25 1.Tracking systems 2.Sensors 3.Readout 4.Infrastructure 5.Material Budget 6.Conclusions 7.More Info Jose E. Garcia Micro-Pattern Gas and Silicon Detectors for Tracking