Latest developments in technologies for detectors

1. Latest developments in technologies for detectors • Outline: • Some general remarks – identifying the areas where new ideas are being implemented • Address various “technologies” – trying to focus on new (or not yet fully applied detector system concepts) • Summary and conclusions • Disclaimer and thanks: • Personal view, so lots of room for biases and mistakes • Many thanks to the people who really do the work, and have generally provided the information in these slides

2. New detector ideas/concepts • The major R&D drivers are Linear Collider detectors and upgrade of LHC detectors – but there are many other detector systems (neutrino – lower rate ad energy, flavour studies – high intensity and lower energy, heavy ion physics – high occupancy, astroparticle systems – low rate and low noise, etc) being planned, investigated or implemented. • Silicon systems • Vertex systems and Large silicon strip systems • Gas detector systems • Micropatterns systems in particular • Calorimeter systems • Particle flow measurements (fine granularity) • Dual mode measurements (scint and cherenkov) • Photo-readout (SiPM) • Electronics, control and readout • Submicron electronics and improved power distribution systems – (the latter possibly our weakest point) • Trigger and data-analysis • Trigger and Data Acquisition – not to mention computing and software – crucial but I have not included here • Also missing are particle identification systems > 100 Million Electronics Channels, 40 MHz ---> hundreds of Hz

3. Vertex detectors • Lots of development activities –focus on material, granularity, radiation hardness, integration … • Motivation is to develop new pixel systems • Radiation hardness improvement • Decrease fabrication cost of pixel detector • Develop thinner pixel systems • New interconnect methods (3D, bonding and vias) • Easy fabrication of large area devices • For example – wishes for a Linear Collider system: • Superb impact parameter resolution ( 5μm ⊕ 10μm/(p sin3/2θ) ) • Excellent space-point precision ( < 4 microns ) • Transparency ( ~0.1% X0 per layer ) • Track reconstruction ( find tracks in VXD alone ) • Requires good angular coverage with several layers close to IP • Sensitive to acceptable number of bunch crossings ( <150 BX = 45 μsec) • Power Constraint (< 100 Watts) – low mass

4. CCD based • Charge-Coupled Devices (CCDs) • Demonstrated in large system (307Mpx) at SLD, but slow ⇒ Column Parallel CCDs (CPCCC) being developed • FPCCD (Fine Pixel CCD) – fully depleted epi-layer to suppress diffusion • Image Sensor with In-Situ Storage (ISIS) • Combines CCDs, active pixel transistors and edge electronics in one device • Charge collected under a photo-gate • Charge is transferred to 20-pixel storage CCD in situ, 20 times during the ~ 1 ms long bunch train

5. MAPS and DEPFET • Monolithic Active Pixel Sensors use the epi-layer of commercial processes for signal formation • Radiation tested with NIEL and gamma, promising • Parallel R&D: FAPS -10~20 storage capacitors/pixel • DEPFET • Fully depleted sensitive volume • Electrons  are  collected  in  ”internal  gate“ and  modulate  the  transistor‐current • Radiation hardness tested

6. Chronopixel and SOI • Double CMOS Pixel • Macro (50 μm pitch) for timing • Micro (5 μm pitch) for precise position • Buffer data during ~3000 bunches in a train and readout between bunch trains • SOI detectors are a first step toward 3D integration since it uses many of the same processes as 3D integration (oxide bonding, wafer thinning, via formation) • Thin top layer with silicon islands in which PMOS and NMOS transistors are built. • A buried oxide layer (BOX) which separates the top layer from the substrate. • High resistivity substrate which forms the detector volume. • Diode implants are formed beneath the BOX and connected by vias.

7. 3D integration Figures from Ray Yarema, talk in Paris 2007

8. High Power consumption Low Power consumption Short Connection Long Connection Low Density High Density Poor Heat Dissipation Good Heat Dissipation RC Delays Reduced RC Delays High Impedance Low Impedance Source : Fraunhofer-IZM Large Area Smallest Area James Lu, RPI, Peaks in Packaging, 2003 Challenging Interposers Simple Interposers Less I/O Pitch limitations I/O Pitch limitations Industry Vision 3D will be used for: memories (memory cards), optical sensors (CMOS), smart cards

9. 3D sensors and Diamonds • Today oxygenated n on n sensors are used in some of the most critical areas of the LHC detectors. Upgrade of some LHC pixels layers nevertheless needed 2012-13 – need very high radiation hardness. • In addition to planar sensors one could consider: • 3D silicon sensors (fig). These have proven to be very radiation hard, depletion thickness depends on p+ and n+ electrode distance, not on the substrate thickness  • Can operate at very low voltages, • Very radiation hardness and fast, • can be active almost to the edge, • Being tested with LHC pixel electronics - promising • Need to prove reliable production • Chemical Vapor Deposition (CVD) Diamond detectors, already being used in all LHC detectors and many other places as beam condition monitors • Signal somewhat lower (bandgap wider), very fast • Radiation hardness also good • Can work at room temperature • See talk of W. Trischuk in parallel session

10. Large silicon strip systems

11. Large scale silicon systems • The most critical parts are the sensors, ASICs and system engineering (mechanics, power, cooling, assembly, etc) • To develop and buy silicon sensors for several hundreds of m2 silicon sensors is not an easy task, for example (from a CMS presentation about upgrade R&D – Gino Bolla): • Extend previous Multi-Geometry studies to substrate thickness less than or equal the pitch • Strip/Pixel capacitance (back-plane, inter-strip/pixel & total) • Critical fields, depletion and break-down voltage • Sensor functionality (charge collection efficiency etc) • Detailed design parameters for masks • Extend previous studies from LHC to SLHC fluence – large irradiation programs needed • Extend previous studies to include MCZ and Epitaxial substrates • Extend previous studies to include n-on-p • Re-produce complementary sets of measurements and simulation • Study biasing, guard rings, isolation methods

12. Micropattern Gas Detectors (MPGD) • Arrived slightly late for LHC – now being considers for almost any area one can imagine, tracking, TPC readout, calorimeter active layers, muon chamber upgrades at LHC … • Focus needed on large systems, reliable operation (gas, materials, construction methods, integration with electronics, etc) … • Gaseous trackers (proportional wire chambers) are limited in • granularity • counting rate (ion tail) • ageing • robustness (broken wires, sparks) • After 1985-90: Gaseous Inner trackers replaced by Si for many applications • 1995 -1996 Invention of Micromegas and GEM solving granularity & counting rate & robustness • Now pushing granularity (pixel-anode readout) – but still not a lot of experience in large experiments

13. MPGDs Slide from Hwanbae Park, Kyungpook Nat’l Univ, LP 2007

14. Gossip: replacement of Si tracker • For tracking, gas is potentially a better detection material than Si : • it is light • primary electrons can simply be multiplied: gas amplification • high electron mobility: fast signals, high count rates are possible • gas can be exchanged: no radiation damage • gas has a low εr: with small voxels the source capacity can be small (10 fF) • allowing fast, low-noise, and low-power preamps • gas is usually cheap • can run at room temperature • BUT • ageing: must be solved and must be understood / under control • discharges/sparks: readout system should be spark proof • diffusion: limits max. drift length • little experience with large systems in high radiation environment • - gas distribution needed Slide(s) from Harry Van Der Graaf

15. Muon systems • Covered partly by micropattern discussion earlier • Trigger chambers in particular for new experiments are not easy • Successful construction for LHC experiments, let us now await operation experience • In general for gas based systems: • In addition to new technologies as MPGD also adaption and improvements of existing ones, improved operation experiences and understanding of ageing, gas mixtures and materials

16. Calorimeters Particle flow: • Need to measure 4-vectors of jets with excellent precision. Physics program relies heavily on final states with (several) bosons: W,Z,H. Necessary to reconstruct W,Z through their hadronic decay modes. Jet energy resolution very important for this multi-jet spectroscopy. • In jet measurements, use the excellent resolution of tracker, which measures bulk of the energy in a jet • Particle Flow Calorimetry requires fine grained EM calorimeter to separate neutral EM clusters from charged tracks entering the calorimeter • Jet resolution goal is 3-4% above 100 GeV Plots and tables on next slides from Wigman, Brau and presentations of Bailey and Lindner in ICHEP parallel sessions

17. ECAL CALICE prototype (1cm2 cell) beam test • Particle Flow Calorimetry requires fine grained EM calorimeter to separate neutral EM clusters from charged tracks entering the calorimeter • One technology choice – Si/W calorimeter (Small Moliere radius) • High granularity (~1cm2 or less) and stable gain. • Small sampling gaps – so not to spoil RM • Separation of charged tracks from jet core helps • Good success using Si/W for Luminosity monitors at SLD, DELPHI, OPAL, ALEPH • Cost : $2-3/cm2 for Si. How far can it go down? Silicon wafer (4x4mm2)

18. Photo-readout - SiPM Resistor Rn= few MΩ • Silicon photomultipliers are semiconductor photon sensitive devices build from an avalanche photodiode matrix on common silicon substrate: • B-field proof, small, good timing resolution, affordable • Total quantum efficiency similar to a traditional PMT • Gain (G) is also similar to a PMT • G vs Vb curve is linear • Dimensions permits extremely compact, light and robust mechanical design • Being explored in many applications today – many companies offering various types • Lot of work ahead to understand for example radiation tolerances and operational parameters Depletion Region R 50 substrate ND280 has chosen to use MPPC as the photosensors for all scintillator detectors. – Need ~50,000 MPPCs for ND280; first large-scale use of these devices Pixel size: ~25 x 25 mm2 to ~100 x 100 mm2 Array size: 0.5 x 0.5 mm2 to 5 x 5 mm2 Hamamatsu MPPC Active area: 1.3x1.3 mm2 Number of pixels: 667

19. Dual readout of calorimeters • An attractive option for improving the quality of hadron calorimetry is the use of Cherenkov light. • Hadronic showers have an em component due to π0, and a non-em component (mostly soft p). The fem (fraction of em energy) varies significantly event by event and e/h is not 1. • Cherenkov light almost exclusively produced by em component. 80% of non-em energy deposited by non relativistic particles • DREAM (Dual REAdout Method) principle (Wigman et al): • Measure fem event by event by comparing Cherenkov and and dE/dx signals • Correct hadronic energy reconstruction, in an in instrument calibrated with electrons • Linearity for hadrons and jets • Gaussian response functions • Energy resolution scale with 1/√E

20. Crygenic liquids • Liquified Nobles and the Detection of WIMP Dark Matter • Cristiano Galbiati • Princeton University • ICHEP’08, Philadelphia, Aug 1 2008 • Scintillation + Ionization • Xenon (XENON, LUX, ZEPLIN) • Argon (WARP, ARDM) • Scintillation • Argon, Neon (CLEAN/DEAP)

21. Deep Sub Micron Electronics • DSM has been essential for the LHC experiments providig access to rad.tolerant reliable high yield processes • Expected to be sufficient for most future experiments moving from 0.25 um downwards – even for LHC upgrades with hundreds of Mrad close to the interaction region • ADCs are good indicators of circuit and technology progress in mixed-signal chips • Standard metric to characterize them is the: FOM=Power/(2Neff * fsample)which is constantly progressing: Plots from A.Marchioro

22. Deep Sub Micron Electronics Summary of talk given by Paul O’Connor in parallel session: • Power dissipation is the major obstacle to further CMOS scaling. • Foundry and mask costs going up as process options (multi-Vth, multi-tox, HBT, passives, etc.) added. • Analog design is compromised by the low supply rail. • NRE cost of ultra-scaled technologies becoming prohibitive for low-volume applications. • Plenty of opportunity to innovate in (n-4)-generation CMOS. Plot from A.Marchioro

23. Powering From F.Faccio • Need to supply ~ 50kW at 1-2 V – hugely inefficient with large losses in cables (P=RI2, so we end up introducing a large amount of copper) • New detectors – lower voltages in DSM processes, higher granularity – we need to change approach and think new

24. Powering solutions • Minimize current through cables by: • a) “recycling” current (Serial Powering) • b) “high-voltage” power lines and local DC-DC converters • Both can significantly reduce services and improve the power distribution schemes • Concerns about safety, stability, relibility, radiation hardness of the solutions – around 20 groups now studying this for LHC upgrades From F.Faccio

25. Powering solutions Interface PCB Cooling hoses with connector Module 0 Module 1 Hybrid 2 Module 3 Module 4 Module 5 Some issues: • radiation levels • magnetic field (no ferrites) • minimum size and mass (“no” shielding) • high currents • extreme reliability • silicon strips sensitive to “pick-up” From M.Weber

26. Summary and Conclusions • A large number of detectors being planned currently – to be constructed over the next 15 years (even more if one includes astroparticle, nuclear physics and synchrotron experiments that use more and more of the same technologies) • Very ambitious ideas out there ready to be used with the potential to provide significantly lower mass, higher granularity and resolutions than ever before • Good cooperation with industry in many areas • Let us not forget the integration – power, cooling, installation and access, radiation/activation issues, machine interface – it is pity that these issues have to re-learnt over and over again, and they might be the determining factors for the overall detector performance (and certainly for the large risk factors) • And don’t forget triggering and computing (even if not covered in this talk)

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