ILC detectors
Taikan Suehara
(Kyushu University)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 1
ILC sales points (cf. LHC)
• Electroweak production
– Predictable process
– Low background
• 4-Momentum conservation
– One more constraints
• High resolution detector(s)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 2
Specialty of ILC detectors
1. Quark flavor tagging capability
– High S/N ratio in b-tagging
– Ability of c-tagging
Vertex
2. Momentum resolution of tracks Tracking
3. Jet energy resolution by Particle Flow
Calorimeter
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 3
ILD
International Large Detector
ILD is larger than SiD
Components:
• Vertex
• Silicon tracking
(SIT/SET/ETD/FTD)
• Gas TPC
• ECAL/HCAL/FCAL
(finely segmented)
• SC Coil (3.5 Tesla)
• Muon in Iron Yoke
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 4
SiD
Silicon Detector
Compact  cheaper
Silicon vertex/track/ECAL
Components:
• Vertex
• Silicon tracker (no gas)
• ECAL/HCAL/FCAL
(finely segmented)
• SC Coil (5 Tesla)
• Muon
concept
Taikan Suehara, MEG collaboration meetingSimilar
@ Fukuoka,
23 Oct. 2013 page 5
Simulation framework
Event generator
(whizard, physsim, etc.)
models  particles
stdhep file
Detector Simulation
(geant4 based: Mokka/SLIC)
particles  hits
LCIO file
Reconstruction (Marlin/org.lcsim)
hits  particles
LCIO file, ROOT file
Analysis (cuts, MVAs, fits...)
particles  models
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 6
LCIO
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 7
Quark flavor tagging
with vertex detector
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 8
Vertex detector: design
b hadrons: ct ~ 400 mm
c hadrons: ct ~ 100 mm
t: ct = 87 mm
BSM quasi-stables
Target: 5 mm position resolution for high-p tracks
within high background environment
e+
g
g
e+
e-
ebeam background
ILD: 3 double layers SiD: 5 single layers
Taikan
MEG
Both
at Suehara,
r=14-15
tocollaboration
60 mm meeting @ Fukuoka, 23 Oct. 2013
page 9
Vertex detector: technologies
Many hits overlaid – pixel detector!
ILC beam: 1300 bunches with 300 nsec interval
Two options:
• Faster readout (to reduce bunches to be overlaid)
• CMOS-type, SOI, 3D, MAPS, etc.
• Smaller pixels (to reduce occupancies by hits)
• Fine pixel CCD (bonus: better resolution)
Technologies developing
Vertex detector is the last to be installed
- options can be delayed for ~ 5 years
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 10
Faster readout: many techs.
CMOS: readout in 32 ms
(~ every 100 bunches)
with 20 x 20 mm pixels
Chronopixel: aims to
specify bunch on every hits
20 x 20 mm pixels
3D sensor
in 23
development
Taikan
collaboration meeting
@ Fukuoka,
Oct. 2013 page 11
DEPFET: will
beSuehara,
used MEG
in Belle2
Fine Pixel CCD
KEK, Tohoku, Shinshu + Hamamatsu
5 x 5 mm pixel (goal), 6 x 6 mm (current)
occupancy will be < 3% at 250 & 500 GeV
after integrating all bunches in a train
•
•
•
•
•
•
Readout: OK (6 x 6 mm with larger horizontal shift register)
50 mm thickness is realized
Full well capacity (~6K electrons) is not satisfactory
Beam test planned  cancelled due to J-PARC accident
Neutron damage test done at CYRIC (Tohoku)  measuring
CO2 two phase cooling: to be tested
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 12
Expected Performance
ILD
< 5 mm impact parameter resolution with 20 mm pixels
1-2 mm impact parameter resolution with 5 mm pixels
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 13
Vertex finder
track
q
D
IP
Vertex-IP
line
Secondary vertex
Single track vertex
(nearest point)
Incorporated in LCFIPlus package
• Build-up method is used for secondary vertex finder
• Does not require jet direction (avoid jet ambiguity)
 better in multi-jet environments (ZHH etc.)
• Single track can be used to be assigned to second vertex
to identify b-c cascade decay
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 14
Flavor tagging
In LCFIPlus package
• Multivariate analysis (BDT)
• Separated by # of vertices
• Vertex position/mass/tracks
• Impact parameters of tracks
• ~ 20 variables
• c-tag depends on vertex resolution
b-tag
c-tag
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 15
Momentum resolution of
tracks
with main tracker (silicon/TPC)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 16
Tracker: design & requirement
Requirements
• High momentum resolution
• Low material
Two approaches
• Silicon-only tracking (SiD)
• Silicon + TPC (ILD)
Both gives similar performance & cost
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 17
Time Projection Chamber
(+ Silicon)
Pros
• Continuous tracking
good for non-pointing tracks
and dense tracks
• dE/dx capability (not yet taken
into account in the simulation)
• 2ns topological time stamping
with inner silicon strips
(two layers in baseline)
Issues/Cons
• Field distortion by ions from gas amplification  ‘gating’
• Cathode plane at z=0
• worse spatial resolution (but we have inner silicon)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 18
TPC amplification & readout
GEM
Micromegas
track at test beam
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 19
Silicon tracking
• Mainly traditional silicon strip
– no active development
• Readout chip is the same as ECAL in SiD –
KPiX – bump-bonded to the sensors
– Test sensor made
– Time stamping at the chip – stored to outside
between trains
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 20
Resolution / material
ILD
SiD
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 21
Tracking software
• ILD tracking (sorry, for SiD I have no info)
• Standalone Silicon tracking (VTX + SIT)
– Kalman filter (partially) – now improving
– Cellular automaton also now being developed
• TPC tracking (Clupatra)
– Kalman filter
• Combining Silicon
+ TPC tracking
Taikan Suehara, MEG collaboration
@ Fukuoka,
Oct.
page 22
trackingmeeting
efficiency
of tt23
62013
jet events
Jet energy resolution
with particle flow calorimetry
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 23
Particle flow calorimetry
Separate each particle in jet
Detector Fraction
Resolution
Charged Particle
Tracker
~ 60%
0.1% / pT sinq
(GeV) for each
Photon
ECAL
~ 30%
15% / E (GeV)
Neutral Hadron
HCAL
~ 10%
60% / E (GeV)
ILC Calorimetry
All
30% / E (GeV)
PFA simulation
Performance of particle flow calorimetry depends on
• Mis-clustering  highly granular calorimeter (esp. ECAL)
• Energy resolution of neutral hadrons  HCAL
• Jet clustering dominates in many-jet (6-, 8-jet) final states
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 24
Calorimeter: design
• Starting at r~1.8m (ILD)/1.3m (SiD)
• ECAL granularity: 5 mm adopted (both)
– Optimized (roughly) by PFA
– apparently the cost driver (with magnet)
• ECAL thickness: 15-20 cm
– 25 X0
• HCAL granularity: 1-3 cm
• HCAL thickness: ~100 cm
– 6 interaction length
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 25
ECAL
Absorber: W
• 2-2.5 mm thick
• maybe thicker in
outer layers
SiECAL
ScECAL
Readout
several options:
• Silicon ECAL
• Scintillator ECAL
with SiPM
• MAPS
(digital readout,
50 x 50 mm pixel)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 26
Strip scintillator/clustering
• Scintillator strip (5 x 45 mm) is
proposed instead of tiles for ECAL
• Layering horizontal and vertical strips
may come to similar resolution as
5 x 5 mm tiles
• Cost is almost half of SiECAL
hybrid of SiECAL and ScECAL
performance close to tile
is alsoTaikan
being
investigated
Suehara,
MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 27
HCAL
• Design is almost the same in ILD and SiD
• Absorber: Fe
• Detector: 2 options
– RPC with digital readout: 1 x 1 cm2
– Scintillator with analog readout: 3 x 3 cm2
(strip is not considered now)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 28
PandoraPFA
Sophisticated algorithm of track-cluster matching
used in ILC community for > 5 years – no substitute
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 29
Optimization for particle flow
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 30
Jet clustering
• Jet clustering is the performance driver
in many-jet (>=6) final states
• Usual Durham clustering, using
• Many ideas, not so successful...
– Using reconstructed vertices to be separated
• good for some cases, used default now
– Color-singlet clustering
• connect jets with more particle between them
– Kinematic constrained jet clustering
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 31
Other things
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 32
Magnet/Yoke/Muon
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 33
Forward detectors
• Important to tag
t-channel background
• Used for BSM with
forward particles
• Luminosity meas.
• Detectors
–
–
–
–
LumiCal
LHCAL
BeamCal
pair monitor (beam size measurement) (optional)
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 34
Push-pull
• Two detectors
are on platform
• Change the
detector to be
used
(changing time
is assumed to
be a week or 2)
• Experts say it’s possible
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 35
Summary
• Novel technologies are adopted to ILC
detectors to employ best possible
performance
• Key improvements are
– Vertex detector for b/c tagging
– Tracker with excellent momentum resolution
– PFA calorimeter
• Detector optimization has now being started,
in terms of physics performance.
Taikan Suehara, MEG collaboration meeting @ Fukuoka, 23 Oct. 2013 page 36