LargeHuge Detector Concept

1
Large/Huge Detector Concept

• 9. Nov. 2004
• _at_7th ACFA LCWS in Taipei
• Y. Sugimoto
• KEK

2
Background
3
History of ACFA detector study

• 1992 Dec. JLC-I report (JLC Detector)
• 2T solenoid, R4.5m
• Compensating EM- and H-CAL, 2.5ltRlt4.0m
• Small-cell Jet chamber, 0.45ltRlt2.3m, L4.6m
• 2001 Nov. ACFA report
• 2003 Sep. GLC report (GLC Detector)
• 3T solenoid, R4m ?Pair B.G. suppression
• Compensating EM- and H-CAL, 1.6ltRlt3.4m
• Small cell Jet chamber, 0.45ltRlt1.55m, L3.1m (
  ?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

4
Large/Huge detector study so far

• Actually, discussion on Large/Huge detector study
  has started before the ITRP decision
• Started discussion after 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 RD for GLC detector started in 2003
• RD for the calorimeter of GLC detector optimized
  for PFA (digital calorimeter) has proposed in
  Aug. 2003

5
Design Concept
6
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

7
Optimization for PFA

• Jet energy resolution
• sjet2 sch2 sg2 snh2 sconfusion2
  sthreashold2
• Perfect particle separation
• 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

8
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 B0,
  photon energy inside a certain distance from a
  charged track scales as Rin2)
• Different approaches
• B Rin2 SiD
• B Rin2 TESLA
• B Rin2 Large/Huge Detector

9
Effective Moliere Length
xg
xa
Effective Moliere Length Rm (1xg/xa)
Gap Sensor R.O. elec etc.
Absorber W Rm 9mm Pb Rm 16mm
10
Central Tracker

• Figure of merit

n is proportional to L if sampling pitch is
constant ?
11
A possible modification from GLC detector model

• Larger Rmax (2.0m) of the tracker and Rin (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 lt l (4.3m?) both for
  neutron b.g. and QC support (l distance between
  IP and QC1)

12
Comparison of parameters
1 GLD is a tentative name of the Large/Huge
detector model. All parameters are
tentative.
13
Comparison of parameters
14
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)

15
Global geometry
(All parameters are tentative)
16
Global geometry
17
Global geometry
GLD is smaller than CMS Large is smaller than
Compact ?
18
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

19
Detector Components
20
Detector components

• EM Calorimeter
• Small Rmeff ?
• W radiator
• Make gaps as small as possible
• Small segmentation sseg lt 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 RD and detector
  simulation

21
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

(TESLA TDR)
22
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
• Si inner/outer(?) tracker
• Time stamping capability
  (separation of
  bunches)
• High resolution Si strip det.
• improves momentum resolution
• Si endcap tracker
• Improves momentum resolution
• in the end-cap region where main
  
  tracker coverage is limited

SIT s7mm, 3 layers VTX s3mm, 5 layers
23
Detector components

• Si forward disks / Forward Calorimeter
• Tracking down to cosq0.99
• Luminosity measurement
• 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
• Si pair monitor
• Measure beam profile from r-phi distribution of
  pair-background
• Radiation-hard Si detector (Si 3D-pixel)

24
Detector components

• 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
• RD for thin wafer is very important to
  compensate for the degradation of I.P. resolution
  at low momentum due to large Rmin
• TOF (?)
• K-p separation by dE/dx of TPC has a gap in
  0.92 GeV/c
• TOF system with s100ps can fill up the gap
• 1st layer of ECAL or additional detector ?
• What is the physics case?

25
Detector components

• TOF (Cont.)

Assumptions d(TOF)100ps L2.1m d(dE/dx)4.5
K-p Separation (s)
Momentum (GeV/c)
26
Status of the study
27
Full Simulator

• Installation of a new geometry into a full
  simulator JUPITER is under way

28
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.Bs result ? need more
  investigation

F
dcut
29
Charged g separation

• Simulation by J.C. Brient (LCWS2004)

ee- ? ZH ? jets at Ecm500GeV
SD (6T)
TESLA (4T)
30
Magnet

• ANSYS calculation by H.Yamaoka
• Field uniformity in tracking region is OK
• Geometry of muon detector is tentative. More
  realistic input is necessary

31
Other studies

• See presentations in parallel sessions and
  http//ilcphys.kek.jp/

32
Summary

• 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 RD should be written
• A lot of jobs including clarification of physics
  requirements, detector full/quick simulation, and
  detector RD are awaiting us
• Please join the Kick-off meeting Date Nov. 10
  Time 1730 - 1930 Place Room 204

33
Backup slides
34
Pair background track density

• Beam Calorimeter is placed in the high background
  region

Same sign
Opposite sign
GLC Parameter, B4T
by T.Aso