Calorimetry and Muons Summary Talk Andy White University of Texas at Arlington LCWS05, SLAC March 22, 2005

 Physics processes driving calorimetry and muon systems designs  Calorimeter system design  Different approaches to LC calorimetry  Integrated detector design issues  Electromagnetic Calorimeter Development  Hadron Calorimeter Development  Muon system/tail-catcher  Timescales - where we go from here! Overview of talk Note: Simulation and algorithm work reviewed in next talk.

Physics examples driving calorimeter and muon system design Jet energy resolution Muon From M.Battaglia – Large Detector Meeting/Paris 2005

Physics examples driving calorimeter design Higgs production e.g. e + e - -> Z h separate from WW, ZZ (in all jet modes) Higgs couplings e.g. - g tth from e + e - -> tth -> WWbbbb -> qqqqbbbb ! - g hhh from e + e - -> Zhh Higgs branching ratios h -> bb, WW *, cc, gg,  Strong WW scattering: separation of e + e - -> WW -> qqqq e + e - -> ZZ -> qqqq and e + e - -> tt Missing mass peak or bbar jets

Physics examples driving calorimeter design -All of these critical physics studies demand:  Efficient jet separation and reconstruction  Excellent jet energy resolution  Excellent jet-jet mass resolution + jet flavor tagging Plus… We need very good forward calorimetry for e.g. SUSY selectron studies, and… ability to find/reconstruct photons from secondary vertices e.g. from long-lived NLSP ->  G

Calorimeter system/overall detector design Initially two general approaches: (1)Large inner calorimeter radius -> achieve good separation of e, , charged hadrons, jets,… Matches well with having a large tracking volume with many measurements, good momentum resolution (BR 2 ) with moderate magnetic field, B ~2-3T But… calorimeter and muon systems become large and potentially very expensive… However…may allow a “traditional” approach to calorimeter technology(s). EXAMPLES: Large Detector, GLD

Large Detector GLD Detectors with large inner calorimeter radius

Calorimeter system/overall detector design (2) Compact detector – reduced inner calorimeter radius. Use Si/W for the ECal -> excellent resolution/separation. Constrain the cost by limiting the size of the calorimeter (and muon) system. This then requires a compact tracking system -> Silicon only with very precise (~10  m) point measurement. Also demands a calorimeter technology offering fine granularity -> restriction of technology choice ?? To restore BR 2, boost B -> 5T (stored energy, forces?) EXAMPLE: SiD

SiD Compact detector

Area of EM CAL (Barrel + Endcap) –SD: ~40 m 2 / layer –TESLA: ~80 m 2 / layer –LD: ~ 100 m 2 / layer –(JLC: ~130 m 2 / layer) How big ?? Very large number of channels for ~0.5x0.5cm 2 cell size!

Can we use a “traditional” approach to calorimetry? (using only energy measurements based on the calorimeter systems) 60%/  E 30%/  E H. Videau Target region for jet energy resolution

Results from “traditional” calorimeter systems - Equalized EM and HAD responses (“compensation”) - Optimized sampling fractions EXAMPLES: ZEUS - Uranium/Scintillator Single hadrons 35%/  E  1% Electrons 17%/  E  1% Jets 50%/  E D0 – Uranium/Liquid Argon Single hadrons 50%/  E  4% Jets 80%/  E Clearly a significant improvement is needed for LC.

A possible approach to enhancing traditional calorimetry The DREAM (“Dual REAout Module)project – high resolution hadron calorimetry: Use quartz fibers to sample e.m. component (only!), in combination with scintillating fibers Structure How to configure for a LC detector?

The Energy Flow Approach Energy Flow approach holds promise of required solution and has been used in other experiments effectively – but still remains to be proved for the Linear Collider! -> Use tracker to measure Pt of dominant, charged particle energy contributions in jets; photons measured in ECal. -> Need efficient separation of different types of energy deposition throughout calorimeter system -> Energy measurement of only the relatively small neutral hadron contribution de-emphasizes intrinsic energy resolution, but highlights need for very efficient “pattern recognition” in calorimeter. -> Measure (or veto) energy leakage from calorimeter through coil into muon system with “tail-catcher”.

Don’t underestimate the complexity!

What is a jet?

Note: - It is popular to quote the averages of these distributions, however -there are wide variations, and we will have to develop efficient procedures for events with e.g. 25% neutral hadrons, 40% EM (all photons?), 35% Charged hadrons > Challenging task to find all neutral clusters (and not mis-associate them with a track!)

Integrated Detector Design Tracking system EM Cal HAD Cal Muon system/ tail catcher VXD tag b,c jets

Integrated Detector Design So now we must consider the detector as a whole. The tracker not only provides excellent momentum resolution (certainly good enough for replacing cluster energies in the calorimeter with track momenta), but also must: - efficiently find all the charged tracks: Any missed charged tracks will result in the corresponding energy clusters in the calorimeter being measured with lower energy resolution and a potentially larger confusion term.

Integrated Detector Design - provide excellent two track resolution for correct track/energy cluster association -> tracker outer radius/magnetic field size – implications for e.m. shower separation/Moliere radius in ECal. - Different technologies for the ECal and HCal ?? - do we lose by not having the same technology? - compensation – is the need for this completely overcome by using the energy flow approach?

Integrated Detector Design - Services for Vertex Detector and Tracker should not cause large penetrations, spaces, or dead material within the calorimeter system – implications for inner systems design. - Calorimeters should provide excellent MIP identification for muon tracking between the tracker and the muon system itself. High granularity digital calorimeters should naturally provide this – but what is the granularity requirement? - We must be able to find/track low energy ( < 3.5 GeV) muons completely contained inside the calorimeter.

Calorimeter System Design  Identify and measure each jet energy component as well as possible Following charged particles through calorimeter demands high granularity… Two options explored in detail: (1) Analog ECal + Analog HCal - for HCal: cost of system for required granularity? (2) Analog ECal + Digital HCal - high granularity suggests a digital HCal solution - resolution (for residual neutral energy) of a purely digital calorimeter??

Calorimeter Technologies Electromagnetic Calorimeter Physics requirements emphasize segmentation/granularity (transverse AND longitudinal) over intrinsic energy resolution. Localization of e.m. showers and e.m./hadron separation -> dense (small X 0 ) ECal with fine segmentation. Moliere radius -> O(1 cm.) Transverse segmentation  Moliere radius Charged/e.m. separation -> fine transverse segmentation (first layers of ECal). Tracking charged particles through ECal -> fine longitudinal segmentation and high MIP efficiency. Excellent photon direction determination (e.g. GMSB) Keep the cost (Si) under control!

SLAC-Oregon Si-W ECal R&D Readout development – M.Breidenbach

CALICE – Si/W Electromagnetic Calorimeter Wafers: Russia/MSU and Prague PCB: LAL design, production – Korea/KNU Evolution of FE chip: FLC_PHY3 -> FLC_PHY4 -> FLC_TECH1 New design for ECal active gap -> 40% reduction to 1.75m, R m = 1.4cm

CALICE-ECal - results Move (completed) module to Fermilab test beam late 2005

ECal work in Asia Rt= a layer / tungsten = 15.0/3.5 = 4.8 (CALICE ~ 2) Eff. Rm = 9mm * (1 + Rt) = 52mm Total 20 layers = 20 X0, 30cm thick 19 layers of shower sampling Si/W ECal prototype from Korea Results from CERN beam tests 2004: 29%/  E (vs. 18%/  E for GEANT4) S/N = 5.2 Fit curve of 29%/√E

ECal work in Asia (Japan-Korea-Russia) Fine granularity Pb-Scintillator with strips/small tiles and SiPM New GLD ECal design Previous Pb/Scint module with MAPMT readout Study covering Laser hitting area (9 pixels) ECal test at DESY in 2006? YAG - 2  m precision

Scintillator/W – U. Colorado Half-cell tile offset geometry Electronics development is being pursued with industry

Hybrid Ecal – Scintillator/W with Si layers – LC-CAL (INFN) The LCcal prototype has been built and fully tested. Energy and position resolution as expected:  E /E ~ % /  E,  pos ~2 mm 30 GeV) Light uniformity acceptable. e/  rejection very good ( <10 -3 ) 45 layers 25 × 25 × 0.3 cm 3 Pb 25 × 25 × 0.3 cm 3 Scint.: 25 cells 5 × 5 cm 2 3 planes: ×.9 cm 2 Si Pads at: 2, 6, 12 X %  E Low energy data (BTF) confirmed at high energy !!! e -  =2.16 mm  =2.45 mm  =3.27 mm Si L1 Si L2 Si L3

Calorimeter Technologies Hadron Calorimeter Physics requirements emphasize segmentation/granularity (transverse AND longitudinal) over intrinsic energy resolution. - Depth  4 (not including ECal ~ 1 ) -Assuming EFlow: - sufficient segmentation to allow efficient charged particle tracking. - for “digital” approach – sufficiently fine segmentation to give linear energy vs. hits relation - efficient MIP detection - intrinsic, single (neutral) hadron energy resolution must not degrade jet energy resolution.

Hadron Calorimeter – CALICE/analog Minical – results from electron test beam Full 1m 3 prototype stack – with SiPM readout. Goal is for Fermilab test beam exposure in Spring 2006 APD chips from Silicon Sensor used AD , Ø 1.1 mm, U bias ~ 160 V SiPM APD

Hadron Calorimeter – CALICE/analog Cassette production Support structure being provided by DESY for test beam at Fermilab

Hadron Calorimeter – CALICE/digital (1) Gas Electron Multiplier (GEM) – based DHCAL 500 channel/5- layer test mid -’05 30x30cm 2 foils Recent results: efficiency measurements confirm simulation results, 95% for 40mV threshold. Multiplicity 1.27 for 95% efficiency. Next: 1m x 30cm foil production in preparation for 1m 3 stack assembly. Joint development of ASIC with RPC

Hadron Calorimeter – CALICE/digital (2) Resistive Plate Chamber-based DHCAL Pad array Mylar sheet Aluminum foil 1.1mm Glass sheet Resistive paint (On-board amplifiers) 1.2mm gas gap -HV GND Low noise TestsResults ChargeAvalanche mode ~0.1 ÷ 5 pC Streamer mode 5 ÷ 100 pC EfficiencyGreater than 95 % Drops to zero at spacer Streamer fractionPlateau of several 100 V where efficiency > 95% and streamer fraction < few percent 1 – gas gap versus 2 – gas gapLarger Q with 1 – gas gap Similar efficiency Noise rateSmall ~0.1 – 0.2 Hz/cm 2 Different gasesBest: Freon:IB:SF 6 = 94.5:5:0.5

Muon System/Tail Catcher - Muon identification/measurement essential for LC physics program. - Role(s) of muon system/tail catcher: -> Identify high Pt muons exiting calorimeter/coil. But…how much can we do with calorimeter alone? -> ? Contribute to muon Pt measurement ? Poor hit position resolution, but long lever arm… -> Measure the last pieces of high energy hadron showers penetrating through the coil – but, this is really measuring the “tail of the tail”. -> ? Identify possible long-lived particles from interactions?

Muon Technologies Scintillator-based muon system development Extruded scintillator strips with wavelength shifting fibers. Readout: Multi-anode PMTs GOAL: 2.5m x 1.25m planes for Fermilab test beam U.S. Collaboration

Muon Technologies European – CaPiRe Collaboration Frascati

TCMT – CALICE/NIU Goal: Test Beam Fermilab/2005 SiPM location Extrusion Cassette

CALICE SiW ECAL CALICE TILE HCAL+TCMT Combined CALICE TILE OTHER ECALs CALICE DHCALs and others Combined Calorimeters PFA and shower library Related Data Taking >2009 ILCD R&D, calibration Phase I: Detector R&D, PFA development, Tech. Choice Phase II Phase 0: Prep. Timeline of Beam Tests , tracking, MDI, etc From Jae Yu

Timescales for LC Calorimeter and Muon development W e have maybe 3-5 years to build, test*, and understand, calorimeter and muon technologies for the Linear Collider. By “understand” I mean that the cycle of testing, data analysis, re-testing etc. should have converged to the point at which we can reliably design calorimeter and muon systems from a secure knowledge base. For the calorimeter, this means having trusted Monte Carlo simulations of technologies at unprecedented small distance scales (~1cm), well-understood energy cut-offs, and demonstrated, efficient, complete energy flow algorithms. Since the first modules are only now being built, 3-5 years is not an over-estimate to accomplish these tasks! * See talk by Jae Yu for Test Beam details

GDE (Design) (Construction) Technology Choice Acc CDR TDRStart Global Lab. Det. Detector Outline Documents CDRsLOIs R&D Phase Collaboration Forming Construction Detector R&D Panel Tevatron SLAC B LHC HERA T2K Done! Detector “Window for Detector R&D

Comment on R&D efforts - It is clear that there are a number of parallel/overlapping R&D efforts. - This was inevitable, and desirable, in the early LC R&D period. - R&D funding is generally limited – we must make optimal use of those resources we have. - A World Wide Study R&D panel has been formed. - Each detector concept will survey R&D activity, needs -> Hopefully this will provide a basis for more efficient use of limited R&D resources

CalorimeterTechnologyGroups Electromagnetic Silicon-TungstenBNL, Oregon, SLAC Silicon-TungstenUK, Czech, France, Korea, Russia Silicon-TungstenKorea Scintillator/Silicon-LeadItaly Scintillator/Silicon-TungstenKansas, Kansas State Scintillator-LeadJapan, Russia Scintillator-TungstenJapan, Korea, Russia Scintillator-TungstenColorado CalorimeterTechnologyGroups Hadronic (analog) Scintillator-SteelCzech, Germany, Russia, NIU Scintillator-LeadJapan Hadronic (digital) GEM-SteelFNAL, UTA RPC-SteelRussia RPC-SteelANL, Boston, Chicago, FNAL Scintillator – Steel Northern Illinois/ NICADD Scintillator – Lead/Steel Japan, Korea, Russia Tail catcher Scintillator-SteelFNAL, Northern Illinois RPC-SteelItaly From ACFA 07

CONCLUSIONS - A vigorous program of Linear Collider calorimetry and muon/tail catcher development is underway ! - Many results from prototypes – but we should avoid too much duplication. - A lot of work has been done with very limited detector R&D budgets. - It is critical to carry out an R&D survey and ensure that Detector R&D proceeds in a timely manner alongside Accelerator R&D. This is particularly critical for U.S.-based calorimeter development which faces significant financial hurdles, and a long test beam program!