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.

- gtth from e+ e- -> tth -> WWbbbb -> qqqqbbbb !- ghhh from e+ e- -> Zhh

Higgs branching ratios h -> bb, WW*, cc, gg, ττ

Strong WW scattering: separation of

e+e- -> ννWW -> ννqqqq e+e- -> ννZZ -> ννqqqq

and e+e- -> ννtt

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 -> γG

Calorimeter system/overall detector design

Initially two general approaches:

(1) Large inner calorimeter radius -> achieve good separation of e, γ, charged hadrons, jets,…

Matches well with having a large tracking volume with many measurements, good momentum resolution (BR2) 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 (~10μm) point measurement.

Also demands a calorimeter technology offering fine granularity -> restriction of technology choice ??

To restore BR2, boost B -> 5T (stored energy, forces?)

EXAMPLE: SiD

SiDCompact detector

SD: 1.27m

GLD: 2.1m

TESLA: 1.68

m

• Area of EM CAL (Barrel + Endcap)– SD: ~40 m2 / layer– TESLA: ~80 m2 / layer– LD: ~ 100 m2 / layer– (JLC: ~130 m2 / layer)

How big ??

Very large number of channels for ~0.5x0.5cm2

cell size!

Can we use a “traditional” approach to calorimetry? (using only energy measurements based on the

calorimeter systems)

60%/√E 30%/√E

H. VideauTarget 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!

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Electromagnetic

Neutral Hadrons

Charged Hadrons

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.

Electromagnetic

Neutral Hadrons

Charged Hadrons

25% neutral hadrons, 40% EM (all photons?), 35% Charged hadrons

> Challenging task to find all neutral clusters (and notmis-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 isthe 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 TechnologiesElectromagnetic 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 X0) 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 CalorimeterWafers:

Russia/MSU and Prague

PCB: LAL design, production –Korea/KNU

New design for ECal active gap -> 40% reduction to 1.75m, Rm = 1.4cm

Evolution of FE chip: FLC_PHY3 -> FLC_PHY4 -> FLC_TECH1

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) = 52mmTotal 20 layers = 20 X0, 30cm thick19 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 = 5.2Fit curve of 29%/√E

ECal work in Asia (Japan-Korea-Russia)Fine granularity Pb-Scintillatorwith 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 - 2μm 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:

σE/E ~11.-11.5% /√E, σpos ~2 mm (@ 30 GeV)• Light uniformity acceptable.• e/π rejection very good ( <10-3)

•45 layers

•25 × 25 × 0.3 cm3 Pb

•25 × 25 × 0.3 cm3 Scint.: 25 cells 5 × 5 cm2

•3 planes: 252 .9 × .9 cm2 Si Pads at: 2, 6, 12 X0

11.1%/√E

Low energy data (BTF) confirmed at high energy !!!

e-

σ=2.16 mm

σ=2.45 mm

σ=3.27 mm

Si L1Si L2

Si L3

Calorimeter TechnologiesHadron Calorimeter

Physics requirements emphasize segmentation/granularity (transverse AND longitudinal) over intrinsic energy resolution.

- Depth ≥ 4λ (not including ECal ~ 1λ)

-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 1m3 prototype stack – with SiPM readout. Goal is for Fermilab test beam exposure in Spring 2006

APD chips from Silicon Sensor used

AD 1100-8, Ø 1.1 mm, Ubias~ 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 30x30cm2 foilsRecent 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 1m3 stack assembly.

Joint development of ASIC with RPC

Hadron Calorimeter – CALICE/digital(2) Resistive Plate Chamber-based DHCAL

Pad arrayMylar sheet

Mylar sheet Aluminum foil

1.1mm Glass sheet

1.1mm Glass sheet

Resistive paint

Resistive paint

(On-board amplifiers)

1.2mm gas gap

-HVGND

Low noise

Tests Results

Charge Avalanche mode ~0.1 ÷ 5 pCStreamer mode 5 ÷ 100 pC

Efficiency Greater than 95 %Drops to zero at spacer

Streamer fraction Plateau of several 100 V whereefficiency > 95% and streamer fraction < few percent

1 – gas gap versus 2 – gas gap Larger Q with 1 – gas gapSimilar efficiency

Noise rate Small ~0.1 – 0.2 Hz/cm2

Different gases Best: Freon:IB:SF6 = 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 TechnologiesScintillator-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 TechnologiesEuropean – CaPiRe Collaboration

TB @ 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

20082007 2006 2005 2009 >2009

ILCD R&D, calibration

Phase I: Detector R&D, PFA Phase I: Detector R&D, PFA development, Tech. Choicedevelopment, Tech. Choice

Phase IIPhase IIPhase 0: Phase 0: Prep.Prep.

Timeline of Beam Tests

μ, tracking, MDI, etc

From Jae Yu

Timescales for LC Calorimeter and Muondevelopment

We 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 muonsystems 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)

TechnologyChoice

Acc.

2004 2005 2006 2007 2008 2009 2010

CDR TDR Start Global Lab.

Det. Detector Outline Documents

CDRs LOIs

R&D PhaseCollaboration Forming Construction

Detector R&D Panel

TevatronSLAC BLHCHERA

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

Calorimeter Technology Groups

Silicon-Tungsten BNL, Oregon, SLAC

Silicon-Tungsten UK, Czech, France, Korea, Russia

Silicon-Tungsten Korea

Electromagnetic Scintillator/Silicon-Lead Italy

Scintillator/Silicon-Tungsten Kansas, Kansas State

Scintillator-Lead Japan, Russia

Scintillator-Tungsten Japan, Korea, Russia

Scintillator-Tungsten Colorado

Calorimeter Technology Groups

Scintillator-Steel Czech, Germany, Russia, NIU

Scintillator-Lead Japan

GEM-Steel FNAL, UTA

RPC-Steel Russia

RPC-Steel ANL, Boston, Chicago, FNAL

Scintillator – Lead/Steel Japan, Korea, Russia

Scintillator – Steel Northern Illinois/ NICADD

Scintillator-Steel FNAL, Northern Illinois

RPC-Steel ItalyTail catcher

Hadronic (digital)

Hadronic (analog)From K.Kawagoe @ 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!