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Introduction to Large/Huge Detector study. 10. Nov. 2004 @Kick-off meeting in 7 th ACFA LCWS in Taipei Y. Sugimoto KEK. Organization/Schedule.

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introduction to large huge detector study

Introduction to Large/Huge Detector study

10. Nov. 2004

@Kick-off meeting in

7th ACFA LCWS in Taipei

Y. Sugimoto


organization schedule
  • None of SiD, Middle (TESLA), Large/Huge detector study group is a “Collaboration” in HEP sense. You can contribute to more than one study group. The tails of 3 gaussian peaks overlap with each other.
  • The study groups should be international (World-Wide Study)
  • Actually, inter-regional detector R&D collaborations (Horizontal collaborations, such as LC-TPC, CALICE, SiLC) can contribute to two or three study groups
  • Milestone:
    • Detector cost estimation by WWS costing panel at the end of 2005
    • We hope the concept will survive until CDR (2007?) and TDR (2009?)
    • In a shorter range, we should present study results at LCWS2005 in Mar. at SLAC and Snowmass workshop in Aug.2005.
large huge detector concept
Large/Huge detector concept
  • GLC detector as a starting point
  • Optimization mainly for PFA
    • Larger main tracker outer radius/ECAL inner radius
    • Larger Z position of EC CAL inner surface
    • Longer tracker/solenoid
  • Keep B field 3T (Stored EVTX(beam b.g.)/TPC(duffusion) resolution)
  • Re-consider the optimum sub-detector technologies based on the recent progresses
  • GLC Detector: Baseline detector (Minimum performance) Large/Huge Detector: State-of-art detector (Performance to get maximum physics output), backed up with simulation studies and detector R&D (anticipated in near future)
simulation study
Simulation study
  • Select minimum set of physics processes without duplication of final-state topology for the detector benchmark
  • For the moment, the topology up to 4-fermion final state with and without missing energy should be considered
  • There are two types of detector performances:
    • Process-dependent: Detector performance can be determined only when the physics process is specified. It affects the physics output, of course.
      • c- and b- tagging efficiency
      • Jet energy resolution
    • Process-independent: Detector performance is rather independent of process, but affects physics output
      • Pt resolution
      • Particle ID capability (K/p, m)
      • Minimum veto angle
    • Anything else?
simulation study1
Simulation study
  • Other basic simulations
    • Detector full simulation specific to each sub-detector or combination of sub-detectors, but rather independent of physics processes. For example;
      • Tracking efficiency of vertex detector with beam background
      • Effect of tail catcher on the neutral hadron E resolution
      • Effect of two-photon background on the TPC resolution
      • Pt resolution v.s. number of sampling
    • The results of these simulations become inputs to or bases of the benchmark simulations
detector r d


Main tracker

Solenoid magnet

Si inner tracker

Vertex detector

Si pair monitor

Muon system

Si outer tracker

Si endcap tracker

Si forward disks

Forward calorimeter

Beam calorimeter


DAQ system/Trigger(?)

Detector R&D
  • Too many study issues to be summarized as an introduction
  • A lot of jobs including clarification of physics requirements, detector full/quick simulation, and detector R&D are awaiting us
  • Defining the jobs may be the first job to be done
detector components
Detector components
  • EM Calorimeter
    • Small Rmeff 
      • W radiator
      • Make gaps as small as possible
    • Small segmentation : sseg < Rmeff
  • Hadron Calorimeter
    • Options
      • Absorber: Pb or Fe ?
      • Sensor: Scintillator or GEM ?
      • Digital or not digital ?
      • Tail catcher behind solenoid needed?
  • Choice of calorimeter options depends on the results of future detector R&D and detector simulation
detector components1
Detector components
  • Main tracker
    • TPC is a natural solution for the Large tracker
      • Positive ion feedback (2-g background) ?
      • Study of gas with small diffusion
    • Small-cell jet chamber as an option (End plate would be much thicker than TPC)
  • Solenoid magnet
    • Field uniformity in a large tracking volume
    • Is 2mm limit really needed?


detector components2
Detector components
  • Muon system
    • No serious study for GLD so far
    • Design of muon system is indispensable for the solenoid/iron-yoke design, which takes large fraction of the total cost
    • How many layers? How thick? Which detector option?
  • Si inner/outer(?) tracker
    • Time stamping capability (separation of bunches)
    • High resolution Si strip det.

improves momentum resolution

    • Z-measurement needed?
  • Si endcap tracker
    • Improves momentum resolution

in the end-cap region where main tracker coverage is limited

SIT: s=7mm, 3 layers

VTX: s=3mm, 5 layers

detector components3
Detector components
  • Si forward disks / Forward Calorimeter
    • Tracking down to cosq=0.99
    • Luminosity measurement
    • What is the beam background environment?
  • Beam calorimeter
    • Not considered in GLC detector
    • At ILC, background is 1/200. Need serious consideration
    • Careful design needed not to make back-splash to VTX
    • Minimum veto angle ~5mrad (?)  Physics
    • Crossing angle?
  • Si pair monitor
    • Measure beam profile from r-phi distribution of pair-background
    • Radiation-hard Si detector (Si 3D-pixel)
    • What happens if crossing angle is 24mrad?
detector components4
Vertex Detector

Relatively low B-field of Large/Huge detector requires larger radius of the innermost layer Rmin (pair background)

Detailed simulation of background (pair b.g. and synchrotron b.g. ) is necessary to determine Rmin and beam pipe radius

R&D for thin wafer is very important to compensate for the degradation of I.P. resolution atlow momentum due to large Rmin

TOF (?)

K-p separation by dE/dx of TPC has a gap in 0.9–2 GeV/c

TOF system with s=100ps can fill up the gap

1st layer of ECAL or additional detector ?

What is the physics case?

Detector components
history of acfa detector study
History of ACFA detector study
  • 1992 Dec. “JLC-I” report (JLC Detector)
    • 2T solenoid, R=4.5m
    • Compensating EM- and H-CAL, 2.5<R<4.0m
    • Small-cell Jet chamber, 0.45<R<2.3m, L=4.6m
  • 2001 Nov. “ACFA report”
  • 2003 Sep. “GLC report” (GLC Detector)
    • 3T solenoid, R=4m: Pair B.G. suppression
    • Compensating EM- and H-CAL, 1.6<R<3.4m
    • Small cell Jet chamber, 0.45<R<1.55m, L=3.1m ( Keep ptmin same as before) Degraded pt res.
  • 2004 Aug. ITRP technology choice
    • Good chance to re-start a new detector optimization study
    • Regional study  Inter-regional (world-wide) study
    • Milestone: Detector cost estimation at the end of 2005
large huge detector study so far
Large/Huge detector study so far
  • Actually, discussion on Large/Huge detector study has started before the ITRP decision
    • Started discussionafter LCWS2004
    • Brief presentation at Victoria US WS (Jul.2004)
    • Presentation at Durham ECFA WS (Sep.2004)
    • Detector full simulator (JUPITER) construction on going
  • Discussion on the key components has started still earlier
    • TPC R&D for GLC detector started in 2003
    • R&D for the calorimeter of GLC detector optimized for PFA (digital calorimeter) has proposed in Aug. 2003
a possible modification from glc detector model
A possible modification from GLC detector model
  • Larger Rmax (1.552.0m) of the tracker and Rin (1.62.1m) of ECAL
    • TPC would be a natural solution for such a large tracker
  • Keep solenoid radius same:

 Somewhat thinner CAL (but still 6l), but does it matter?

  • Use W instead of Pb for ECAL absorber
    • Effective Rm: 25.5mm  16.2mm (2.5mm W / 2.0mm Gap)
    • Small segmentation by Si pad layers or scintillator-strip layers
  • Put EC CAL at larger Z (2.05m2.8m)  Longer Solenoid
    • Preferable for B-field uniformity if TPC is used
  • It is preferable Zpole-tip < l* (4.3m?) both for neutron b.g. and QC support (l* :distance between IP and QC1)
a possible modification from glc detector model1
A possible modification from GLC detector model
  • New faces
    • Si Endcap Tracker
    • Si Outer Tracker
    • Beam Calorimeter
    • TOF
basic design concept
Basic design concept
  • Performance goal (common to all det. concepts)
    • Vertex Detector:
    • Tracking:
    • Jet energy res.:

 Detector optimized for Particle Flow Algorithm (PFA)

  • Large/Huge detector concept
    • GLC detector as a starting point
    • Move inner surface of ECAL outwards to optimize for PFA
    • Larger tracker to improve dpt/pt2
    • Re-consider the optimum sub-detector technologies based on the recent progresses
optimization for pfa
Optimization for PFA
  • Jet energy resolution
    • sjet2 = sch2 + sg2 + snh2 + sconfusion2 + sthreashold2
    • Perfectparticleseparation:
  • Charged-g/nh separation
    • Confusion of g/nh shower with charged particles is the source of sconfusion  Separation between charged particle and g/nh shower is important
    • Charged particles should be spread out by B field
    • Lateral size of EM shower of g should be as small as possible ( ~ Rmeffective: effective Moliere length)
    • Tracking capability for shower particles in HCAL is a very attractive option  Digital HCAL
optimization for pfa1
Optimization for PFA
  • Figure of merit (ECAL):
    • Barrel: B Rin2/ Rmeffective
    • Endcap: B Z2/ Rmeffective

Rin : Inner radius of Barrel ECAL

Z : Z of EC ECAL front face

(Actually, it is not so simple. Even with B=0, photon energy inside a certain distance from a charged track scales as ~Rin2)

  • Different approaches
    • B Rin2 : SiD
    • B Rin2 : TESLA
    • BRin2 : Large/Huge Detector
effective moliere length
Effective Moliere Length



Effective Moliere Length = Rm(1+xg/xa)

Gap : Sensor + R.O. elec + etc.


W : Rm ~ 9mm

Pb : Rm ~ 16mm

central tracker
Central Tracker
  • Figure of merit:

n is proportional to L if sampling pitch is constant

merits and demerits of large huge detector
Merits and demerits of Large/Huge detector
  • Merits
    • Advantage for PFA
    • Better pt and dE/dx resolution for the main tracker
    • Higher efficiency for long lived neutral particles (Ks, L, and unknown new particles)
  • Demerits
    • Cost ? – but it can be recovered by
      • Lower B field of 3T (Less stored energy)
      • Inexpensive option for ECAL (e.g. scintillator)
    • Vertex resolution for low momentum particles
      • Lower B requires larger Rmin of VTX because of beam background
      • d(IP)~5  10/(pbsin3/2q) mm is still achievable using wafers of ~50mm thick
comparison of parameters
Comparison of parameters

[1] GLD is a tentative name of the Large/Huge detector model.

All parameters are tentative.

detector size
Detector size
  • EM Calorimeter
  • Area of EM CAL

(Barrel + Endcap)

    • SiD: ~40 m2 / layer
    • TESLA: ~80 m2 / layer
    • GLD: ~ 100 m2 / layer
    • (JLC: ~130 m2 / layer)
global geometry
Global geometry

(All parameters are tentative)

global geometry2
Global geometry

GLD is smaller than CMS

“Large” is smaller than “Compact” 

detector components5
Detector components
  • TOF (Cont.)





K-p Separation (s)

Momentum (GeV/c)

full simulator
Full Simulator
  • Installation of a new geometry into a full simulator “JUPITER” is under way
charged g separation
Charged – g separation
  • Simulation by A. Miyamoto
    • Events are generated by Pythia6.2, simulated by Quick Simulator
    • Particle positions at the entrance of EM-CAL
    • Advantage of Large/Huge detector is confirmed
    • Inconsistent with J.C.B’s result  need more investigation



charged g separation1
Charged – g separation
  • Simulation by J.C. Brient (LCWS2004)

e+e-  ZH  jets at Ecm=500GeV

SD (6T)


  • ANSYS calculation by H.Yamaoka
    • Field uniformity in tracking region is OK
    • Geometry of muon detector is tentative. More realistic input is necessary
other studies
Other studies
  • See presentations in parallel sessions and
  • Optimization study of Large/Huge detector concept has just started
  • GLC detector is the starting point of the Large/Huge detector, but its geometry and sub-detector technologies will be largely modified
  • A key concept of Large/Huge detector is optimization for PFA
  • A milestone of this study is the detector cost estimation scheduled at the end of 2005. A firm report backed up with simulation studies and detector R&D should be written
  • A lot of jobs including clarification of physics requirements, detector full/quick simulation, and detector R&D are awaiting us
  • Please join the Kick-off meeting: Date: Nov. 10 Time: 17:30 - 19:30 Place: Room 204

Pair background track density

  • Beam Calorimeter is placed in the high background region

Same sign

Opposite sign

GLC Parameter, B=4T

by T.Aso