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E-Flow Optimization of the HCAL for a LC Detector – ANL Status Report

E-Flow Optimization of the HCAL for a LC Detector – ANL Status Report. S. Magill , A. Bamberger*, S. Chekanov, G. Drake, S. Kuhlmann, B. Musgrave, J. Proudfoot, J. Repond, R. Stanek, R. Yoshida Argonne National Laboratory. ANL R&D Goals E-flow Optimization Progress RPC Readout R&D

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E-Flow Optimization of the HCAL for a LC Detector – ANL Status Report

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  1. E-Flow Optimization of the HCAL for a LC Detector – ANL Status Report S. Magill, A. Bamberger*, S. Chekanov, G. Drake, S. Kuhlmann, B. Musgrave, J. Proudfoot, J. Repond, R. Stanek, R. Yoshida Argonne National Laboratory • ANL R&D Goals • E-flow Optimization Progress • RPC Readout R&D • Summary * Permanent address – Freiburg University

  2. LC HCAL R&D Goals at ANL - Motivation Physics Requirement : separate W, Z using dijet mass in hadronic decay mode (~70% BR) Detector Goal : measure jets with energy resolution /E ~ 30%/E • Optimize HCAL to be used with ECAL and Tracker in E-flow jet reconstruction – • Charged particles ~ 60% of jet energy -> Tracker • Photons ~ 25% of jet energy -> ECAL • Neutral Hadrons ~ 15% of jet energy -> HCAL Calorimeter challenge : charged/neutral shower separation requires high granularity, both transverse and longitudinal, to reconstruct showers in 3-D

  3. LC HCAL R&D Goals at ANL – Scope of Work • Optimize, in simulation, the design for an HCAL which, when used in an E-flow jet reconstruction algorithm, can reconstruct jets with /E ~ 30%/E. • study absorber type/thickness with JAS, standalone GEANT3 program • tune transverse granularity and longitudinal segmentation in JAS • test both analog and digital readout techniques • optimize E-flow algorithm • Investigate the feasibility of using Resistive Plate Chambers (RPCs) as the active media in the HCAL. • avalanche vs streamer mode • noise reduction, signal optimization, readout schemes • Develop electronics readout schemes for the optimized HCAL. • digital vs multi-threshold analog • efficient data compression

  4. Towards HCAL Optimization   Jet E Resolution (% x E)  Digital Analog Readout Log10 Cell Size (cm2) • How we will optimize HCAL : • Cell size determination • Separation of charged/neutral clusters in 3-D • Cluster algorithms • E-weighted cell association to clusters (analog readout) • Tracking clusterer (digital readout) • Fine tuning of absorber type density : W/Pb/U vs SS/Cu and thickness

  5. Java Analysis Studio (JAS) e+e- ZZ (500 GeV CM) • SD Detector : • ECAL • 30 layers • W(0.25 cm)/Si(0.04 cm) • ~20 X0, 0.8 I • ~5 mm X 5 mm cells • HCAL • 34 layers • SS(2.0 cm)/Scin(1.0 cm) • ~40 X0, 4 I • ~1 cm X 1 cm cells • Modified SD A: • ECAL • 30 layers • W(0.25 cm)/Si(0.04 cm) • ~20 X0, 0.8 I • ~1 cm X 1 cm cells • HCAL • 60 layers • W(0.7 cm)/Scin(1.0 cm) • ~120 X0, 4.5 I • ~1 cm X 1 cm cells • Modified SD B: • ECAL • 30 layers • W(0.25 cm)/Si(0.04 cm) • ~20 X0, 0.8 I • ~1 cm X 1 cm cells • HCAL • 60 layers • W(0.7 cm)/Scin(1.0 cm) • ~120 X0, 4.5 I • ~3 cm X 3 cm cells Soon to come – 5 cm X 5 cm HCAL cells -> ECFA/DESY HCAL

  6. JAS Example – Neutral Particles in CAL • Charged particles in tracker • Neutral particles in CAL • -  in ECAL • - KL0, n, nbar in HCAL

  7. Photon Analysis Analog Readout /mean ~ 15% Analog Readout – perfect Gamma cluster

  8. Photon Analysis Digital Readout non-linear behavior for dense showers /mean ~ 24% Digital Readout – perfect cluster Digital worse than analog readout

  9. KL0 Analysis – SD Detector Analog Readout /mean ~ 30% Compare to digital 

  10. linear behavior for hadron showers KL0 Analysis – SD Detector Digital Readout /mean ~ 26% Average : ~43 MeV/hit Analog EM + Digital HAD x calibration

  11. KL0 Analysis – Modified SD • Analog Readout SD B (3 cm X 3 cm) SD A (1 cm X 1 cm) /mean ~ 35% /mean ~ 26%

  12. KL0 Analysis – Modified SD • Digital Readout SD B (3 cm X 3 cm) SD A (1 cm X 1 cm) /mean ~ 25% /mean ~ 20%

  13. HCAL (only) Digital Results SD B SD 1 cm X 1 cm /mean ~ 28% SD A /mean ~ 32% 3 cm X 3 cm /mean ~ 28% 1 cm X 1 cm

  14. E-Flow Algorithm Systematic Approach : Tracks first (60%), Photons next (25%), Neutral hadrons last (15%) • 1st step -Track extrapolation thru Cal – substitute for Cal cells in road (core + tuned outlyers) – Cal granularity optimized for separation of charged/neutral clusters • 2nd step - Photon finder (use shower shape info) • 3rd step -Neutral hadron clusterer • 4th step –Jet Algorithm on E-flow objects • or • 3rd step -Jet Algorithm on Tracks and Photons • 4th step –include remaining Cal cells in jet (cone?)

  15. RPC Readout Development         • Using RPC from FNAL (P. Mazur) : • size: 25 x 25 cm2 • gas gap 2 mm • glass plates 2 mm thickness • resistive electrodes 40 kOhm/square • pad readout behind the anode electrode • gas: Ar 30% Isob. 8% Freon 62% (a la BELLE) • pad structure of 4x4 cm2, 2x2 cm2, 1x1cm2 • coupled to to give configurations • all pads + frame • all pads • 5(4x4)+2(2x2) cm2  • 4x4+2(2x2) cm2  

  16. Chamber Operation • avalanche mode observed for HV < 8.2 kV, few pC charge • change to streamer mode HV > 8.5 kV few 100pC • streamer mode has multiple streamers as HV increases, charge of a streamer is a slow function of the HV • streamers are seperated in time, but merge at HV > 9.2 kV • efficiency > 95% • single rate compatible with cosmics

  17. Readout of pads • size of the pad is varied for finding the spatial extension of the induced charge • effective size has a radius of about 6 cm • known to depend on the resistivity of the HV electrodes, here: 40 kOhm/square • measure charge of streamers for events at readout pad, compare with those taken at a distance of ~ 6 cm Cross talk (intergration time here: 100 ns) Next steps : higher resistivity of electrodes reduces lateral coupling of the pads.

  18. Summary • Starting studies of HCAL optimization for E-Flow jet analysis • optimal transverse cell size and longitudinal segmentation • optimal absorber material/thickness • analog vs digital readout • Starting development of E-Flow analysis tools • cluster algorithms for analog/digital modes • separation algorithms for clusters • Studying characteristics of RPC readout for HCAL

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