1. Mark ThomsonLCUK Meeting, Oxford CALICE STATUS Mark Thomson University of Cambridge  Overview  UK Hardware  UK Simulation  UK Reconstruction  Conclusions For the CALICE-UK groups: Birmingham, Cambridge, Imperial, Manchester, RAL, UCL

2. Mark ThomsonLCUK Meeting, Oxford Calorimetry at a Future LC  Much LC physics depends on reconstructing invariant masses from jets in hadronic final states  Kinematic fits don’t help – Beamstrahlung, ISR  Jet energy resolution is of vital importance 62 % charged particles : 27 %   : 10 % K L,n : 2 % The Energy Flow/Particle Flow Method The energy in a jet is: Reconstruct momenta of individual particles avoiding double counting Charged particles in tracking chambers Photons in the ECAL Neutral hadrons in the HCAL (and possibly ECAL)  need to separate energy deposits from different particles

3. Mark ThomsonLCUK Meeting, Oxford Calorimeter Requirements ECAL granularity more important than energy resolution, i.e. $$$  e K L,n   Separation of energy deposits from individual particles  Discrimination between EM and hadronic showers small X 0 and R Moliere : compact showers small X 0 / had high lateral granularity : O(R Moliere ) longitudanal segmentation  Containment of EM showers in ECAL Energy flow drives calorimeter design:

4. Mark ThomsonLCUK Meeting, Oxford Calorimeter Concept  ECAL and HCAL inside coil  Better performance – but impacts cost ECAL: silicon-tungsten (SiW) calorimeter: Tungsten : X 0 / had = 1/25, R Moliere ~ 9mm (gaps between Tungsten increase effective R Moliere ) Lateral segmentation: 1cm 2 matched to R Moliere Longitudinal segmentation: 40 layers (24 X 0, 0.9 had ) HCAL: digital vs. analogue (major open question): Tile HCAL (Analogue readout) Steel/Scintillator sandwich Lower lateral segmentation 5x5 cm 2 (motivated by cost) Digital HCAL High lateral segmentation 1x1 cm 2 but digital readout RPCs, GEMS…

5. Mark ThomsonLCUK Meeting, Oxford CALICE Collaboration  Study calorimetry for a future linear collider  Proposed high-granularity ECAL/HCAL $$$ need to fully justify/optimize the calorimetry for FLC  Testbeam studies of ECAL and HCAL ECAL studies of Si-W calorimeter HCAL studies of both analogue and digital options GOALS:  Demonstrate technical feasibility of ECAL  Validate MC simulation (particularly hadronic showers ) vital for optimisation of final design  Study digital vs analogue HCAL PEOPLE:  177 people, 27 institutes (including DESY)  23 UK collaborators ! AIMS

6. Mark ThomsonLCUK Meeting, Oxford UK Contribution  Readout and DAQ for test beam prototype Provide readout electronics for the ECAL (Possibly use UK boards for some HCAL options) DAQ for entire system  Simulation studies ECAL cost/performance optimisation Impact of hadronic/electromagnetic interaction modelling on design. Comparisons of Geant4/Geant3/Fluka  Reconstruction/Energy Flow Started work towards ECAL/HCAL reconstruction Ultimate goal – UK Energy flow algorithm  Luminosity spectrum from Bhabha acolinearity (UCL)

7. Mark ThomsonLCUK Meeting, Oxford HCAL ECAL 1m Beam monitor DAQ Test Beam and Prototype Moveable table  Combined ECAL & HCAL  Engineering Run late 2004 in e - beam at DESY (ECAL only)  Physics Run in 2005 p/  beam at FNAL (TBC)  HCAL: 38 layers Fe  Insert combinations of:  “digital” pads (350k, 1x1cm 2 pads)  GEM  RPC  “analogue” tiles (8k, 5x5cm 2 )  Scintillator tiles

8. Mark ThomsonLCUK Meeting, Oxford Prototype ECAL  3x10 layers, Si-W 0.4X 0, 0.8X 0, 1.2X 0  Each layer 3x3 wafers  Each wafer 6x6 pads 9720 channels total External Readout (VFE) Wafers Si/W/Si Sandwich Carbon Fibre/ Tungsten

9. Mark ThomsonLCUK Meeting, Oxford Readout Overview  CALICE ECAL has 9720 channels  Each gives analogue signal, 14-bit dynamic range  Very-front-end (VFE) ASIC (Orsay) multiplexes 18 channels to one output line  VFE-PCB handles up to 12 VFEs (216 channels)  Cables from VFE-PCBs go directly to UK VME readout boards, called Calice ECAL Readout Cards (CERCs)  Based heavily on CMS tracker readout Rutherford Laboratory –Adam Baird, Rob Halsall, Ed Freeman Imperial College London –Osman Zorba, Paul Dauncey University College London –Matt Warren, Martin Postranecky Manchester University –Dave Mercer

10. Mark ThomsonLCUK Meeting, Oxford Prototype design completed last summer Two prototype boards fabricated last year Arrived on November 21 at Rutherford Laboratory CERC status Currently under stand-alone tests in the UK Aim to test with a VFE-PCB in the UK very soon Move UK hardware to Paris (Ecole Polytechnique) for cosmic tests with fully populated VFE- PCB with Si wafers in Feburary Front End FPGAs Back End FPGA

11. Mark ThomsonLCUK Meeting, Oxford Outstanding Issues  Final path for data has several complex steps  FE digitises ADC data for each trigger  Automatically transferred to 8MByte memory  Memory read from VME when bandwidth available  Needs data transfer, memory control and VME interface  BE FPGA firmware not yet functional  Memory components delayed in delivery; not yet mounted on CERCs  Aiming for end of March for all this to be working !  Backup for VFE tests  Implement simple RS232 interface from PC to BE and hence to FEs  RS232 reads FIFO one word at a time directly to PC  8MByte memories bypassed, must read each event before next trigger  Rate is slow ~1Hz for events; sufficient for cosmics

12. Mark ThomsonLCUK Meeting, Oxford Schedule  VFE tests in Paris in February Essential test of prototypes before moving to production  Possible AHCAL test in April Need more information on what is required; number of channels, interface specification for VFE-PCB equivalent,…  Finalise redesign by end March  Re-layout/fabricate 9 production CERCs in April-May Simple fixes for the few known problems may be possible If so, maybe no need to re-layout; save a month Only have components for nine boards; need to know early if more wanted for HCAL Will need non-UK funds for HCAL readout  Full ECAL system tests from July onwards  On schedule for DESY ECAL test beam in Oct/Nov

13. Mark ThomsonLCUK Meeting, Oxford Test Beam Requirements  Use MC studies to study what data would be most useful in validating MC models (David Ward)  e.g. Compare samples of histo 5 GeV  + in Geant3 (histo) and Geant4 (points)  Significant differences seen at the level of 10 4 events  HCAL shows greatest discrepancies 5 GeV  +  What Data ? Proton/pion/muon ?  How much data ?

14. Mark ThomsonLCUK Meeting, Oxford Differences depend on Energy 1 GeV  + 50 GeV  +  Therefore scan over energies

15. Mark ThomsonLCUK Meeting, Oxford Protons vs Pions 5 GeV p 5 GeV  +  Need to understand beam ! i.e. pion/proton ratio  Find protons/neutrons v. similar (at least in MC)  Greater differences for Scintillator HCAL vs. RPC

16. Mark ThomsonLCUK Meeting, Oxford Test Beam : Conclusions  1% precision suggests >10 4 events per particle type and energy.  Would like energies from 1-80 GeV (~10-15 energy points?).  Pions and protons desirable (Čerenkov needed). +Electrons (+ muons?) for calibration.  Need to understand beam  Both RPC and Scintillator HCAL needed.  Position scan – aim for 10 6 events/energy point?  Also some data at 30-45 o incidence.

17. Mark ThomsonLCUK Meeting, Oxford Study of hadronic models (G Mavromanolakis, N. Watson) Compare: (G Mavromanolakis) Geant 3 with Gheisha Geant 3 / Gheisha (SLAC version) Geant 3 / Fluka Geant 3 / Fluka / Micap (used for n < 20 MeV) Geant 4 / Mokka Also Studying:  Variations of Geant 3/Geant 4 cutoffs (G Mavromanolakis)  Geant 4 FLUKA (N.Watson) - Geant 3 version deprecated - Geant 4 implementation extremely interesting - tricky to get working, but making excellent progress

18. Mark ThomsonLCUK Meeting, Oxford Calorimeter Reconstruction  High granularity calorimeter – very different from previous detectors  `Tracking calorimeter’ Requires new approach to reconstruction Already a lot of good work on powerful energy flow algorithms Still room for new ideas/ approaches Current codes : inflexible UK Effort just starting (Chris Ainsley) Important for future analysis and `energy flow’ studies/detector optimisation

19. Mark ThomsonLCUK Meeting, Oxford ECAL Clustering  Aim – to produce a flexible algorithm, not tied to specific geometry/MC program. Algorithm needs to cope with tracks and clusters Sum hits within cell; apply threshold of ⅓ MIP Form clusters in layer 1 of ECAL. Associate each hit in layer 2 with nearest hit in layer 1 within cone of angle . If none, initiate new cluster. Track onwards layer by layer through ECAL and HCAL, looking back up to 2 layers to find nearest neighbour, if any.

20. Mark ThomsonLCUK Meeting, Oxford Example Events 15 GeV  - 15 GeV e - (Reconstructed clusters are colour-coded, black = highest energy cluster) Handles CLUSTERS and TRACKS

21. Mark ThomsonLCUK Meeting, Oxford Some more difficult examples 15 GeV  15 GeV  -  Separates nearby ECAL clusters  So far things look good, but this is just the first stage

22. Mark ThomsonLCUK Meeting, Oxford Conclusions  CALICE ECAL prototype progressing well - test beam before end of 2004 !  Confident that UK Electronics/DAQ will be ready  Work on Digitization simulation starting (D.Bowerman, C.Fry)  UK contributing significantly to understanding FNAL test beam requirements  On-going studies of hadronic models  UK reconstruction effort starting - important for analysis of test beam data - important for optimisation of ECAL design  Next 2 years are going to be very interesting  UK groups well placed to participate in analysis of test beam data

23. Mark ThomsonLCUK Meeting, Oxford

24. Mark ThomsonLCUK Meeting, Oxford RPC vs. Scintillator HCAL Scintillator RPC

25. Mark ThomsonLCUK Meeting, Oxford Neutrons vs Protons 5 GeV p 5 GeV n

26. Mark ThomsonLCUK Meeting, Oxford  Eight Front End (FE) FPGAs control all signals to front end electronics via front panel input connectors  Back End (BE) FPGA gathers and buffers all event data from FE and provides interface to VME  Trigger logic in BE for timing and backplane distribution; only active in one board  Each input is one full or two half-full VFE-PCBs; need 45 inputs = 6 CERCs  Based on CMS tracker readout (FED) CERC overview

27. Mark ThomsonLCUK Meeting, Oxford Readout Details  Based on CMS silicon tracker readout (FED) Will “borrow” a lot of firmware from them Unfortunately not yet as well-developed as hoped  Dual 16-bit ADCs and 16-bit DAC DAC fed back for internal as well as front end calibration ADC 500kHz; takes ~80ms to read and digitise event data from VFE-PCB  No data reduction in readout board ECAL event size: 3.5 kBytes per board, 20 kBytes total per event  On-board buffer memory; 8 MBytes No buffering available in ECAL front end; receive data for every trigger Memory allows up to ~2k event buffer on readout board during beam spill VME readout speed ~20 MBytes/s; several seconds readout after spill  Large amount of unused I/O from BE FPGA to backplane Will implement trigger logic and control/readout interface to VME in BE