The GLD Concept

MDI Issues Impact on Detector Design

L* Background (back-scattered e+- ,, n) into VTX, TPC Crossing angle Minimum veto angle for 2-photon process (imp

ortant for SYSY search), back-scattered e+- into VTX Pair background VTX radius Synchrotron radiation Beam pipe / VTX radius, background hit

s in trackers Muons Detector hit occupancy Neutrons from the extraction line Radiation damage on Si DID TPC resolution Anti-solenoid Design of very forward detectors Beam timing Readout scheme of VTX, etc. etc.

GLD detector concept study includes all these issues. The baseline design should be compatible with the most severe

case: High Lumi option

Requirement from Physics Impact parameter: b = 5 10/(psin3/2) m (c/b-tagging) Momentum: pt/pt2 = 5x10-5 /GeV (e.g. H recoil mass reconstruction from Zpairs) Jet energy: E/E = 30%/E1/2

(W/Z invariant mass reconstruction from jets) Hermeticity: =5 mrad (for missing energy signatures, e.g. SUSY) Sufficient timing resolution to separating events from different bunch-

crossings Must also be able to cope with high track densities due to high boost and/or

final states with 6+ jets, therefore require: High granularity Good pattern recognition Good two track resolution

General consensus: Calorimetry drives ILC detector design

Calorimetry at the ILC Much ILC physics depends on reconstructing invariant masses

from jets in hadronic final states Kinematic fits won’t necessarily help – Missing particles (e.g. ) +

Beamstrahlung, ISR Aim for jet energy resolution ~ Z for “typical” jets Jet energy resolution is the key to calorimetry The best jet energy resolution is obtained by reconstructing

momenta of individual particles avoiding double counting Charged particles (60%) by tracker Photons (30%) by ECAL Neutral hadrons (10%) by ECAL+HCAL

Particle Flow Analysis The dominant contribution to jet energy resolution comes from

“confusion”, not from single-particle resolution of CAL Separation of particles by fine segmentation / large distance from the IP

is important for CAL

Calorimetry: Optimization for PFA

To avoid the “confusion” and get good jet energy resolution, separation of particles is important for CAL: How? Fine segmentation of CAL High B field Large distance from the IP Large Detector

Often quoted “Figure of Merit”:

22

2

MR

BR

: CAL granularityRM: Effective Moliere length

Calorimetry: B or R? B-field just spreads out energy deposits from charged particles in jet

–not separating neutral particles or collinear particles Detector size is more important – spreads out energy deposits from

all particles R is more important than B

Dense Jet: B-field

neutral

+ve

- ve

Dense Jet: B=0

neutral

+ve

- ve

GLD Concept: Investigate detector parameter space with large detectorsize (R) and slightly lower magnetic field (B) and granularity

GLD Baseline Design Large gaseous central tracker: TPC Large radius, medium/high granularity ECAL: W-Scint. Large radius, thick(~6), medium/high granularity HCAL: Pb-Scint. Forward ECAL down to 5mrad Precision Si micro-vertex detector Si inner/forwad/endcap trackers Muon detector interleaved with iron structure Moderate B-field: 3T

VTX, IT not shown

Vertex detector Role: Heavy flavor tagging

Important for many physics analyses: e.g. Higgs branching ratio measurement

Efficient flavor tagging requires excellent impact parameter resolution:

Goal: = 5 10/(psin3/2) m Sensor technologies

Must cope with high background rate Readout 20 times/ train, or Fine pixel (20 times more pixels)

option : readout once/ train

Vertex detector Main design consideration

Inner radius: Beam pipe radius: Dense core of

pair background should not hit the beam pipe B-dependence not so large: ~B-1/2

Large machine-option dependence Back scattered e+- from BCAL (L

ow-Z mask in front of BCAL should cover down to R<RVTX )

Layer thickness: As thin as possible to minimize m

ultiple scattering I.P. resolution / tracking efficienc

y for low p particles GLD baseline design

Fine pixel CCD Inner/outer radius: 20(?) – 50 mm Angle coverage: |cos|<0.9/0.95

Si trackers

Role: Cover large gap between TPC and VTX Si Inner Tracker (IT) TPC and endcap ECAL Si Endcap Tracker (ET)

to get better Track finding efficiency Momentum resolution Track-cluster maching in ECAL (PFA)

Design optimization Number of layers and their position Wafer thickness Strip or pixel? for the very forward region

Main tracker: TPC

Performance goal: pt/pt2 = 5x10-5 /GeV combined with IT and VTX

Advantages of TPC Large number of 3D sampling

Good pattern recognition Identification of non-pointing tracks

(V0 or kink particles) : e.g. GMSB SUSY

Good 2-hit resolution Minimal material Particle ID using dE/dx

G~~

e+ e- ZH X

TPC

Baseline design Inner radius: 40 cm Outer radius: 200 cm Half length: 230 cm Readout: ~200 radial rings

Open questions Readout: GEM or Micromegas? Material budget of inner/outer wall and end plate Background hit rate and its effect on spatial resolution due t

o positive ion buildup (occupancy is OK even with 105 hits in 50s)

Tracking performance

GLD conceptual design achieves the goal of pt/pt2 = 5x10-5 /GeV

pt/p

t2 (G

eV

-1)

By A.Yamaguchi(Tsukuba)

Monte Carlo

Calorimeter

Performance requirement Goal for jet energy resolution is E/E = 30%/E1/2

Then, what is the requirement for CAL? The answer is not simple. We need a lot of simula

tion study of PFA

ECAL Current baseline design

33 layers of [3mm W + 2mm Scinti. + 1mm gap (readout elec.)]

~28 X0, ~1 , RM~18mm Wavelength shifter fiber + MPC

(Multi-pixel Photon Counter, =SiPM) readout

4cmx4cm tile and 1cm-wide strips Granularity has to be optimize

d by PFA simulation study Calibration method for small s

egments is worrisome Very fine segmentation with Si f

or first few X0 is also discussed

MPC 400pixels

MPC 100pixels (10x10pixels)

~85um

~100um

HCAL Current baseline design

50 layers of [20mm Pb + 5mm Scinti. + 1mm gap (readout elec.)]: (“Hardware compensation” configuration)

~6 Wavelength shifter fiber + MPC

(Multi-pixel Photon Counter, =SiPM) readout

20cmx20cm tile and 1cm-wide strips Granularity has to be optimized

by PFA simulation study Digital HCAL is also considered a

s an option Open questions

Global shape: Octagon, dodecagon, or hexadecagon?

How to extract cables?

Hamamatsu MPC (H100) spectrumUp to ~40 photon peak! is observed

FCAL/BCAL

BCAL Locates just in front of final Q Coverage: down to ~5mrad W/Si or W/Diamond (No detailed

design yet)

FCAL Z~2.3m Also work as a mask protecting

TPC from back-scattered photon from BCAL

W/Si (No detailed design yet)

Muon detector / Magnet Muon detector

Possible technology: Scintillator strip array read out with wavelength shifter fiber + MPC

Number of layers, detector segmentation, etc. have to be studied

Magnet 8 m 3T superconducting sol

enoid Stored energy: 1.6 GJ Excellent field uniformity for

TPC:

mmdzBz

Brz2max

0

Cost Issues Major cost consumers: Solenoid, HCAL, ECAL Solenoid

Cost~0.523xE(MJ)0.662 [PDG]~70M$ HCAL

Volume~230m3, Area (all layers)~87Mcm2

Cost~87M x cost/cm2

ECAL Volume~22m3, Area (all layers)~37Mcm2

Cost~37M x cost/cm2

Requirement for granularity from physics determines the CAL design and the cost: Simulation study is urgent

Summary GLD design study is being carried out both from accelerator point

of view and from physics point of view ILC detectors should be optimized for PFA performance, and

large detectors are suitable for that In GLD concept study, we investigate detector parameter space

with large detector size and slightly lower B and CAL granularity Baseline design of GLD has been shown, but current GLD

baseline design is not really optimized. More simulation study, sub-detector R&D effort, and new ideas are necessary The purpose of this workshop