Testbeam Requirements for LC Calorimetry S. R. Magill for the Calorimetry Working Group Physics/Detector Goals for LC Calorimetry E-flow implications for.
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Testbeam Requirements for LC Calorimetry S. R. Magill for the Calorimetry Working Group Physics/Detector Goals for LC Calorimetry E-flow implications for CAL Design/Testing Optimization for E-flow Testbeam Goals Hardware/Readout mode tests E-flow/Detector simulation validation/verification Test Beam Programs and Venues Summary
Physics/Detector Goals for LC Calorimetry -> higher statistics physics analyses Physics Requirement : separately id W, Z using dijet mass in hadronic decay mode (~70% BR) -> higher statistics physics analyses Detector Goal : measure jets with energy -> /E ~ 30%/ E resolution -> /E ~ 30%/ E Calorimeter challenge : match tracks to charged hadrons – requires separation of charged/neutral hadron showers in Cal, and isolation of photons –> E-flow approach -> high granularity, both transverse and longitudinal, to reconstruct showers in 3-D W, ZW, Z 30%/ M 75%/ M For example, explore EWSB thru the interactions : e + e - -> WW and e + e - -> ZZ -> Requires Z,W ID -> Can’t always use (traditional) constrained fits
E-Flow Implications for Calorimetry Traditional Standards Hermeticity Uniformity Compensation Single Particle E measurement Outside “thin” magnet (~1 T) E-Flow Modification Hermeticity Optimize ECAL/HCAL separately Longitudinal Segmentation Particle shower reconstruction Inside “thick” coil (~4 T) Optimized for best single particle E resolution Optimized for best particle shower separation/reconstruction
ECAL E-flow Optimization For good isolation of photon showers : -> small r M (Moliere radius) – dense calorimeter -> If the transverse segmentation is of size r M, get optimal transverse separation of electromagnetic clusters -> If X 0 / I is small, then the longitudinal separation between starting points of electromagnetic and hadronic showers is large All of the above help to separate hadron showers as well Some examples : Material Z A X 0 / I Fe 26 56 0.0133 Cu 29 64 0.0106 W 74 184 0.0019 Pb 82 207 0.0029 U 92 238 0.0016 Priorities : 1)Measure (isolated) photon energy 2)Separate charged/neutral hadron showers A dense ECAL with high granularity (small transverse size cells), high segmentation (many thin absorber layers), and with X 0 / I small is optimal for E-Flow. -> 3-D shower reconstruction
HCAL E-flow Optimization To optimize the HCAL for E-Flow requires : full containment of (neutral) hadronic showers good precision on energy measurement high segmentation in transverse and longitudinal directions in order to separate in 3-D close-by clusters in jets Integrated approach including other detector sub- components in the design phase, with E-Flow algorithms Assume a tracking system optimized for, e.g., di-lepton measurements Assume a dense ECAL optimized for photon reconstruction Vary HCAL parameters, e.g., absorber material, thickness, size of readout cells in both transverse and longitudinal directions, to determine optimal performance in an E-Flow Algorithm. Priorities : 1)Measure neutral hadron energy 2)Separate charged/neutral hadron showers
Testbeam Goals for Calorimetry Test detector hardware technologies and readout configurations -> flexible configurations of absorber type and thickness, active media types -> linearity, uniformity, signal response, energy resolution, analog/digital readout schemes Study reconstruction algorithms -> flexible configurations of transverse granularity, longitudinal segmentation -> E-flow properties, particle shower shapes -> beam particle tracking? Validate/verify MC simulation -> shower libraries
Calorimeter Hardware/Readout Schemes ECAL Si pixel/W sandwich Analog “SD Detector” Scin Tile/W sandwich Analog Si-Scin/W hybrid Analog Dense Crystals Analog Cerenkov compensated Analog HCAL Scin Tile/SS sandwich Analog “CALICE” Scin “pixels”/SS Digital RPC/SS Digital GEM/SS Digital Same absorber – hanging file configuration at Testbeam?
E-flow/Simulation validation Testbeam Requirements Design of CAL relies on simulation for E-flow algorithm applications Simulations need to be verified in testbeam at particle shower level Ultimate goal is jet energy/particle mass resolution - not possible in test beam So, since EFAs require separation/id of photons, charged hadrons, and neutrals - Verify photon shower shape in ECAL prototype (Si/W with fine granularity - 1X1 cm**2 or better – see plot) Verify pion shower probability in ECAL as function of longitudinal layer Verify pion shower shapes in ECAL/HCAL prototype (must be able to contain the hadron shower both transverse and longitudinally – see plot) Try to get beams with particle energies as in Z jets from e+e- -> ZZ at 500 GeV ->
3 GeV e- in SD Cal Layer Shower Radius (black) Ampl. Fraction (red) 70% of e- energy in layers 3-9 2.6,3.1 13,15.5 5.2,6.2 cm (front,back) ECAL ECAL/HCAL Boundary
10 GeV - in SD Cal Need all 34 layers 20 cm X 20 cm X 30 layer ECAL 80 cm X 80 cm (min.) X 34 layer HCAL Shower Radius (red) Ampl. Fraction (blue) 3.1,5.2 7.8,12.6 15.5,26 cm (front,back) HCAL
Summary of SD Calorimeter Properties On average, 94% of pion energy is contained within an ECAL area of 20 X 20 cm 2 -> 20% of 10 GeV pions appear as MIPS throughout the entire ECAL volume, therefore are 100% contained In the SD CAL, 95% of pion energy is contained for 35% of 10 GeV pions in a 20 X 20 cm 2 ECAL coupled with an 80 X 80 cm 2 HCAL (90% containment for 66% of these pions) -> important to tag leakage from ECAL/HCAL in all directions In a digital SD HCAL, 90% of pion hits are contained in a 90 X 90 cm 2 area -> again, important to tag leakage from ECAL/HCAL in all directions Readout Channels for Testbeam CAL : 30 X 30 cm 2 SD ECAL (0.5 cm X 0.5 cm pixels in 30 layers) -> 108K channels!!! 1 X 1 m 2 SD HCAL (1 cm X 1 cm cells in 40 layers) -> 400K channels!!!
Tagging scintillator paddles surround CAL modules HCAL ECAL Beam halo veto scintillator paddles Beam Wire Chambers (3-views) Scintillator hodoscopes Dead material LC CAL Testbeam Configuration HCAL : 1 X 1 X 1 m 3
Testbeam Programs Several scenarios suggested so far :
Testbeam requirements : a. Electron and photon beam b. Pion and other hadron beam c. Energies of EM and Hadrons: 5 - 150 ~ 250 GeV (If possible as low energies as possible, down to 1~2 GeV) d. Muon beam at energies 1-100 GeV or so --> This is for calorimeter tracking algorithm studies. Testbeam Venues
Summary The Calorimeter Working Group has begun to think about testbeam programs – first working document written which addresses : -> Compatibility of various hardware configurations in the same testbeam area -> Challenge of testbeam programs for E-flow calorimetry -> Challenge of several readout configurations, large number of channels -> First look at possible venues -> Cooperation with European (CALICE) colleagues