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building a tracking calorimeter for the ILC

building a tracking calorimeter for the ILC. Valeria Bartsch University College London. CALICE - french for chalice -. We are searching for the holy grail in energy resolution. Outline. LHC detectors. ILC detector. LEP detectors. Energy Resolution. Particle Flow Algorithms.

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building a tracking calorimeter for the ILC

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  1. building a tracking calorimeter for the ILC Valeria Bartsch University College London

  2. CALICE- french for chalice - • We are searching for the holy grail in energy resolution

  3. Outline LHC detectors ILC detector LEP detectors Energy Resolution Particle Flow Algorithms Dual Readout Tests in testbeam Consequence on DAQ design

  4. A calorimeter for the ILC- comparison with the LHC - LHC & ILC provide a complementary approach • LHC pushes the energy frontier to 14TeV for proton-proton collisions (qq, qg, gg to 0.5-5TeV) • ILC optimised for precision measurements at an energy range 0.1-1TeV for electron-positron collisions • Physics cases for LHC and ILC and their interplay very well studied

  5. A calorimeter for the ILC- comparison with the LHC - LHC: pp  H + X ILC: e+e- H + Z • Electron-positron collider provide a cleaner environment than hadron colliders

  6. A calorimeter for the ILC- comparison with LEP - • LEP ran at 90-115GeV • e+e- Z and e+e- W+W- physics processes dominate • Lepton machine at low energies allow kinematic constraints for mass reconstruction • Energy resolution not vital • ILC is planned to run at the 0.5-1TeV range • Backgrounds dominate • Kinematic fitting not possible due to Beamstrahlung and final states with neutrinos ILC depends critically on the detector performance

  7. A calorimeter for the ILC- ILC machine - • Using superconducting accelerating structures • Collision energy between 0.2-0.5(1.0) TEV • Integrated luminosity 500 fb-1 in the first 4 years • Radiation hardness does not dictate detector design 109 n cm-2 year-1 compared to1014 n cm-2 year-1 at the innermost detectors of the LHC Physics drives the detector design

  8. A calorimeter for the ILC- physics at the ILC - ILC physics: • Higgs sector • SUSY particle spectrum • SM particle … Physics characterised by: • High multiplicity final states (6 - 8 jets) • Small cross sections • Detector optimised for multi-jet environment • sE/E = 30%/√E

  9. A calorimeter for the ILC- effect of energy resolution - sE/E = 30%/√E (0.5 * sE/E of LEP) Energy resolution directly impacts sensitivity (equates to an increase in luminosity) e.g. benchmark process: WW scattering • important to distinguish between: e+e-nnWWnnqqqq from e+e-nnZZ

  10. A calorimeter for the ILC- new approaches to calorimetry - • Particle Flow Algorithms • Approach of the CALICE collaboration • Proposed by 2 of the 3 detector concepts • DREAM concept (also called dual readout) • Proposed by 1 of the 3 detector concepts

  11. Outline LHC detectors ILC detector LEP detectors Energy Resolution Particle Flow Algorithms Dual Readout Tests in testbeam Consequence on DAQ design

  12. A calorimeter for the ILC- DREAM or dual readout approach - • Uses scintillation & clear fibers • Scintillating fibers respond to all charged particles • Clear fibers detect e-/e+ • Dual readout is able to detect fluctuations in the energy resolution due to different response for em and hadronic part of showers

  13. A calorimeter for the ILC- DREAM or dual readout approach - EM shower energy correction improves energy resolution: • Scintillator readout: 49%/√E • Cherenkov light: 86%/√E • combined: 41%/√E Can be further reduced: • in bigger prototypes • Measuring neutron depositions • Technology not yet advanced enough, however at high jet energies clearly a contender

  14. Outline LHC detectors ILC detector LEP detectors Energy Resolution Particle Flow Algorithms Dual Readout Tests in testbeam Consequence on DAQ design

  15. A calorimeter for the ILC- Particle Flow Algorithms (PFA) - • Traditional calorimetry limited by HCAL energy resolution • Use the information provided by the whole detector to improve the energy resolution

  16. A calorimeter for the ILC- Particle Flow Algorithms (PFA)- • Need to be able to match energy deposits and particle tracks • High granularity calorimeter supported by software • Problem: in a multijet environment energy from the same particle can be double counted or energy deposits from different particles not properly separated • Gives rise to the confusion term • Optimize lateral/longitudinal segmentation & software

  17. A calorimeter for the ILC- Particle Flow Approach (PFA)- Optimise the detector for Particle Flow: ECAL • Lateral segmentation = Moliere radius = 1cm for Si/W ECAL • Longitudinal segmentation = about 1 radiation length (in total 30 layers = 24X0) HCAL: • Lateral segmentation less clear (about 1cm) • Longitudinal size limited by constraints that HCAL is inside the magnetic coil = 4-5 interaction lengths

  18. A calorimeter for the ILC- testing the PFA approach - • Behaviour in test beams needs to be tested  MC predictions can be related to real data  PFA predictions can be tested  new methods can be developed • several options for the detector technology possible • these options need to be investigatedin testbeams • High number of readout channels -> more pressure on DAQ  a reliable DAQ system needs to be tested • CALICE collaboration’s goal to test feasibility of PFA

  19. A calorimeter for the ILC- goals of the CALICE collaboration - To provide a basis for choosing a calorimeter technology for the ILC detectors To measure electromagnetic and hadronic showers with unprecedented granularity Physics prototypes Various technologies (silicon, scintillator, gas) Large cubes (1 m3 HCALs) Not necessarily optimized for an ILC calorimeter Technical prototypes Can be only partially equipped Appropriate shapes (wedges) for ILC detectors All bells and whistles (cooling, integrated supplies…) To advance calorimeter technologies and our understanding of calorimetry in general To design, build and test ILC calorimeter prototypes

  20. Outline LHC detectors ILC detector LEP detectors Energy Resolution Particle Flow Algorithms Dual Readout Tests in testbeam Consequence on DAQ design

  21. 0.5cmx0.5cm segmentation results in 100M channels with little room for electronics or cooling Triggerless ~250 GB of raw data per bunch train need to be handled 1st ECAL Module (module 0) HCAL ECAL “Final” Detector A calorimeter for the ILC- concept for the DAQ - ECAL Prototype

  22. A calorimeter for the ILC- time structure - • Interesting time structure, long gaps between bunch trains • In the order of 1000 bunch crossings / bunch train • Time structure heavily used in the design of the data acquisition system • all electronics will be powercycled to decrease cooling need • readout of the system between bunch trains

  23. A calorimeter for the ILC- Very Front End Electronics - ECAL Module-0 (reduced-Z octant) ASICS • Must share readout resource (daisy chain) • Bunch rate too high for instantaneous data transfer. • Too much chip resource to store all events SO: • ‘Auto-trigger’ – store only data over-threshold with pad id + (bunch-number) • <5kByte / bunch-train/ASIC L = 150 cm ASIC (>100 in total!)

  24. A calorimeter for the ILC- EUDET prototype - 38 layers 80000 tiles Typical layer 2m2 2000 tiles Detector Interface Boards Instrument one tower (e.m. shower size) + 1 layer (few 1000 tiles) • 3 different detector types: ECAL, AHCAL, DHCAL • study of full scale technological solutions • prototype expected end of 2009

  25. Host PC Host PC ODR ODR PCIe PCIe DIF DIF DIF DIF Detector Unit Detector Unit Detector Unit Detector Unit A calorimeter for the ILC- DAQ architecture- Detector Unit: ASICs DIF: Detector InterFace connects Generic DAQ and services LDA: Link/Data Aggregator – fanout/in DIFs and drives link to ODR ODR: Off Detector Receiver – PC interface for system. CCC: Clock & Control Card: Fanout to ODRs (or LDAs) CONTROL PC: DOOCS GUI (run-control) 50-150 Mbps HDMI cabling 1-3Gb Fibre LDA Counting Room C&C Detector Storage LDA 10-100m 0.1-1m

  26. A calorimeter for the ILC- DAQ architecture- it is a very important step toward a full detector design

  27. Outline LHC detectors ILC detector LEP detectors Energy Resolution Particle Flow Algorithms Dual Readout Tests in testbeam Consequence on DAQ design

  28. A calorimeter for the ILC- strategy for the testbeam analysis - Build up the analysis in the ECAL and HCAL: • Calibration • Detector stability • Energy resolution • Longitudinal + lateral profile • Comparison of distributions between hadrons and GEANT4 simulations • Detector optimisation • Before looking into PFAs check the fundamentals

  29. A calorimeter for the ILC- main CALICE test beams- DESY electrons 2006 Silicon-ECAL Scintillator ECAL Scintillator HCAL TCMT CERN electrons and pions 2006 and 2007 Silicon-ECAL Scintillator HCAL TCMT (complete) FNAL electrons and pions 2008 Silicon-ECAL Scintillator ECAL Scintillator HCAL TCMT (complete) ……… CERN 2007 14 TB

  30. A calorimeter for the ILC - CALICE Test Beam Activities - • Physics prototype • 30 ECAL layers • 30 HCAL layers • TCMT TCMT HCAL ECAL UK

  31. A calorimeter for the ILC - stability of detectors (e.g. ECAL)- • SiW Tungsten Ecal with up to 9400 cells operated successfully during testbeam campaigns 2006 to 2008 • Stable operation uniform response to MIPs, robust calibration • only 1.4/mill dead cells As expected, a PIN diode silicon detector is stable

  32. A calorimeter for the ILC - dead zones (e.g. ECAL)- E/GeV 2 32 • Need to take geometrical acceptance into account in analysis

  33. A calorimeter for the ILC - dead zones (e.g. ECAL)- • correction restores homogenous • response • energy loss due to acceptance • limits • not fully recovered • important issue for future R&D • requires close collaboration with suppliers 33

  34. A calorimeter for the ILC - linearity & resolution (e.g. ECAL) - Linearity with electrons Resolution with electrons • linearity better than 1% • energy resolution without PFA as expected

  35. A calorimeter for the ILC - shower profiles (e.g. ECAL) - • Transverse shower profile • Moliere radius RM contains • 90% of EM shower energy • independently of energy • RM (W) = 9 mm CALICE preliminary • Longitudinal shower profile • MC describes data very well • leakage energy, shower max can be extracted

  36. A calorimeter for the ILC- leakage energy of the ECAL - For the correct extraction of the leakage energy: • Low energy particles in showers interact differently • Sampling fraction depending on the age of the shower • Need to simulate energy deposition in active and passive layer to extract sampling fraction f: f = Epas/ Etot CALICE preliminary CALICE preliminary

  37. A calorimeter for the ILC- hadrons: resolution and long. Profile - • energy resolution without using PFA • this kind of measurements allows comparisons with GEANT4 • more comparisons especially of the lateral profile are underway 37

  38. A calorimeter for the ILC- overlay of showers - • pion sample with single events and large spread over detector front face • possible to select events with given distance • and overlay offline two showers • advantage  energy of single pion is known select events according to distance and overlay

  39. A calorimeter for the ILC- shower separation - CALICE preliminary efficiency of shower separation: • MC studies for AHCAL geometry optimization •  MC 1 charge + 1 neutral hadron simulated •  data 2 charged pions • MC with HCAL only • data contained showers in AHCAL but ECAL used as tracker

  40. A calorimeter for the ILC- shower separation - CALICE preliminary 3x3x1 qualitative good agreement Only distance <10cm probed by data MC

  41. A calorimeter for the ILC- summary & outlook - • ILC calorimetry can stretch energy resolution to the limit • Particle Flow concept adequate for ILC • Consequence on the calorimeter design: high granularity • CALICE collaboration’s goal is to invest R&D to test PFA idea

  42. A calorimeter for the ILC- outlook - • Test beams (checks alternative technologies, GEANT4 models, PFAs) • Performances well understood • Publications started • Technological prototypes test technical realisation of the needed functionality (including a new DAQ system) • Prototype built for 2010 • Ready for a module zero 2013

  43. A calorimeter for the ILC- spare slides -

  44. A calorimeter for the ILC- concept for the DAQ - • Utilise off the shelf technology • Minimise cost, leverage industrial knowledge • Use standard networking chipsets and protocols, FPGAs etc. • Design for Scalability • Make it as generic as possible • exception: detector interface to several subdetectors • Act as a catalyst to use commodity hardware • PC-based receiver card is a key component in the generic DAQ design

  45. A calorimeter for the ILC- CALICE & the ILC detector concepts-

  46. A calorimeter for the ILC- goal for the energy resolution - • Energy resolution should be in the order of the natural width of the bosons: sm/m  2.5/91 2.1/80.3  0.03 • sE/E  0.03 • Typical jet energies at the ILC: 100-300 GeV • sE/E  0.03/√E Traditional calorimetry limited by HCAL resolution of >50% /√E • new approach needed

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