Physics and Detector
Studies in Japan
Akiya Miyamoto
KEK
ILC Korea meeting @ PAL
17 February 2006
1
Physics Scenario at ILC
2
ILC Detector Performance Goals
(http://blueox.uoregon.edu/~lc/randd.pdf)
 Vertexing
(h  bb ,cc ,    )
 ~1/5 rbeampipe,~1/30 pixel size (wrt LHC)
 ip  5 m  10 m / p sin 3/ 2 

 
 
(e
e

Zh

X; incl. h  nothing )
 Tracking
 ~1/6 material, ~1/10 resolution (wrt LHC)

 (1/ p)  5 105 /GeV
Or better
 Jet energy (Higgs self-coupling, W/Z sep. in SUSY
study)
 ~1/2 resolution (wrt LHC)
 E / E  0.3/ E (GeV )
3
Detector for ILC experiments
Detector design Philosophy
Muon detector
Calorimeter
 Good jet energy resolution
g calorimeter inside a coil
g highly segmented calorimeter
 Efficient & High purity b/c tagging
Coil
g Thin VTX, put close to the IP
g Strong solenoid field
g Pixel type
 High momentum resolution
 Hermetic down to O(10)mrad
Tracker
Vertex
detector
 Shielded enough against beamrelated background
4
Concepts - Technologies
5
GLD Concept




Pixel vertex detector + Si tracker, self-tracking capable
Large gaseous central Time Projection Chamber (TPC)
Large radius, “Medium/High” granularity ECAL: W-Scitillator
“Medium/High” granuality HCAL: Pb-Scintillator inside 3T solenoid
6
Comparison to other concepts
SiD
LDC
GLD
GLD: Large ECAL radius
 good for better jet energy
resolution
7
Our Activities
 Concept Study
 GLD : as an inter-regional team  DOD
 Home page: http://ilcphys.kek.jp/gld/
 Software studies
 Simulation and Reconstruction based on full simulation
 Vertex Detector
 TPC
 Calorimeter
Some topics of recent activities will be presented
Apologies for not covering all
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Software activities
 Development of tools and studies based on them
 Geant4 based full simulator, Jupiter and analysis tools, Satellites
 Study items
 Particle Flow Analysis
–
–
–
–
By cheated method
By realistic method
Performance comparison: digital vs analog, tile size, etc.
Better understanding of hadron shower programs
 Tracking
– Khalman track fitter for TPC/IT/VTX
– Track reconstruction
 Backgrounds in tracker
 Physics performances
 They will be described in the GLD DOD in detail
9
Detector Geometry
in Dec. 2005
Full One Tower
EM + HD
6.1λ
27 X0
New Geometry in Jupiter
(Feb, 2006)
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Perfect PFA
 Perfect track-calorimeter matching based on Monte Calor Info.
 Shower fluctuation, particle interactions with material fully simulated
 Identify terms contributing to the resolution to design the best detector
u,d,s quark pair
Events at Z pole
including a best kink track treatment:
improves kink ~ 1.3 GeV
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PFA : error source
 Contribution to Jet Energy Resolution
Effect of Pt cut
Neutrino
5mrad cut
Low Pt track
TPC Resol.
EM Cal Resol.
HD Cal Resol.
Total
0.30 GeV
0.62
0.83
0
1.36
1.70
2.48
B=6T
Important to measure low Pt track
for the best energy resolution !
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Realistic PFA
 Critical part to complete detector design




Large R & medium granularity vs small R & fine granularity
Large R & medium B vs small R & high B
Red : pion
Importance of HD Cal resolution vs granuality
Yellow :gamma
…
Blue : neutron
 Algorithm developed in GLD:
Consists of several steps





MIP finding
Gamma Finding
Small-clustering
Cluster-track matching
Neutral hadron clustering
ee+
13
PFA performance so far
Z-pole events
 Further improvement
necessary to
 Achieve 30%/Sqrt(E)
 Similar resol.
At higher energy
 Optimize detector w.r.t
jet energy resolution
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Higgs Study
 e+e-  ZH  4-jet or 2-jet + missing :
 Studied assuming the cheated PFA performance, using QuickSim
 Study assuming the realistic PFA performance is in progress
 Other channels such as ZHH or SUSY processes need to be studied
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Higgs mass : if Mh=120GeV
e e 
X;
 e, 
Differential Luminosity(500GeV)
DE/E(beam)~0.1%
Incl. beamstrahlung
350GeV, nominal
(Mh)~109MeV
s / sno min al
Incl. beamstrahlung
350GeV, high-lum
(Mh)~164MeV
Incl. beamstrahlung
250GeV, nominal
(Mh)~27MeV
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Forward Region for SUSY Study
MUD
FCAL Front and Tail: 30 layers of 3mm Thick
Tungsten + 0.3mm thick Si + Air gap
CH2 Mask
TPC
QC1
Response to 10GeV e+
BCAL
EMCAL
BCAL : Total Z length 20 cm
30 layers of 3mm thick Tungsten
+ 0.3mm thick Si. + Air gap
FCAL
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Background
Low energy e+e- pair background in BCAL region.
Simulated using CAIN data, 500 GeV, Nominal parameter
~1/65 bunch of pair backgrounds are simulated
BCAL
e+/e- tagging in the forward region ?
Needs serious study for SUSY physics
FCAL
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VTX R&D in Japan
 Challenge of ILC Vertex detector
 To achieve performance goal, vertex detector has to
 Thin(< 100mt si/layer) pixel device, pt < 5m, # layer > 3
 Bunch spacing, ~300nsec, is too short to readout O(1) Giga pixels,
but occupancy is too high if accumulate 3000 bunches of data with a
standard pixel size of ~ 20x20m2.
 No proven technology exist yet. Candidates are,
 Readout during train
 CPCCD, MAPS, DEPFET, …
 Local signal storage, and readout between train
 ISIS, CAP, FAPS, …
 Fine Pixel, readout between train
 FPCCD (5x5m2 pixel CCD)
 In Japan, we (KEK-Tohoku-Niigata collaboration) are proposing Vertex
Detector using Fine Pixel CCD (FPCCD)
 We believe FPCCD is the most feasible option among the proposed
technologies
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FPCCD Chip
 5m pixels, to reduce occupancy
 Promising, because Fine pixel CCD device exists already for optical
applications
 Fully depleted epitaxial layer to suppress charge spread by diffusion
 Multi-port readout with moderate (~ 15MHz) readout
 Low temperature operation to keep dark current negligible for
200msec readout cycle.
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FPCCD Vertex Detector
 2 layers  Super Layer, 3 super layers in total
minimize the wrong-tracking probability due to multiple scattering
 6 layers for self-tracking capability
 Cluster shape analysis can help background rejection
 Baseline design for GLD
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Background rejection by cluster shape
dW  (WZ BG  WZ Sig ) 2  (W BG  W Sig ) 2
WZSig, WSig: Expected width
A big advantage of Fine Pixel Sensors
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B.G. rejection by cluster shape
 R=20 mm
 Cut at dW=10 m
Ratio
All
dW<10m
Z (mm)
1/20
Z (mm)
23
Status of sensor R&D
 Fully depleted CCD for astrophysics by Hamamatsu
 24 m, 12 m pixel size:
 Available now
 We will test them soon : Charge spread, Lorentz angle
 5 – 9 m pixel size:
 Under development
 Will be available in 0.5 – 1 year
 Custom fully depleted FPCCD for VTX
 High speed (~15MHz)
 Multi-port readout
 We wish to start in 2006
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Challenge of TPC technology
 Principle of TPC
Central
Membrane
Pad Plane
........
E
Bz
Drift Time  Z position
Position at Pad plane
 rposition
 Challenges
 To achieve r<150m after long
drift of > 2m
 MWPC  MPGD readout
 R&D issues
 Gas amplification in MPGD : GEM,
MicroMegas
 Properties of chamber gas:
drift velocity, diffusion
 Ion feedback control
25
TPC R&D
A series of beam tests has been done at KEK PS, to study performances
Of TPC using readouts of MWPC, GEM, and MicroMegas
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Beamtest setup
MPI Field Cage
26cmL
KEK PI2 beamline
Beam
1T Magnet
86cm, 1mL
Readout Pad
10cmx10cm
For MWPC, GEM,
MicroMegas
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MWPC vs GEM
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B Field Dependance
 Bfield improves spatial
resolution significantly.
ILC
Target
 For long drift, diffusion term
dominates the spatial
resolution.
 Calculated results of CD are
more or less consistent with
test results.
 probably OK to extrapolate
to 3~4T
 need to be confirmed by
future tests with large B
field and long drift.
29
Comparison with Numerical Calculation
Neumerical Calculation (by K.
Fujii)
MicroMEGAS
Pad : 2.3 mm
Diffusion Constnat :
469, 285 and 193 m/ cm
for
B = 0, 0.5 and 1.0 T
Neff = 27.5
f :  function
2.3 mm / 12
Data: MicroMEGAS
B=1T
Gas: Ar-isobutane (5%)
Pad: 2.3 mm Pads
Data
 X2   X2 0  D 2 / N eff z
D/
N eff  38.4  9.7 m/
 X 0  129  53 m
diffusion dominant
asymptotic region
cm
Resistive Anode or Digital
 Resolution with short drift length
is dominated by
 Readout pad pitch
 Width of induced charge on pad
plane.
KEK Beamtest : MicroMegas TPC and
a registive anode readout
 To increase pad picth
 Digital TPC : O(100m) pad size
and readout  Future possibility
 Increase signal width
 Resistive anode pad readout,
but two track separation might be
scarified
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Plan of TPC R&D
 Study properties of MPGD, GEM and MicroMegas, and gas
amplification mechanism well  Simulation/ test bench studies
 Study chamber gas properties and amplification in MPGD
 Drift velocity, diffusion constants, …
 For ILC application, gas with no H is preferred to reduce effects of
neutrons background.
 Positive ion feed back has to be reduced sufficiently
 Study properties of MPGD with large prototype  EUDET
 Design and develop a large TPC system with electronics.
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Calorimeter
 Design goals
 Fine granularity, O(1) cm, for the best track-cluster matching
 Crucial for best jet energy resolution
 Hermetic down to O(10)mrad
 Elemag and hadron calorimeters are both inside Coil
 Challenge:
 Achieve sufficient granularity with a reasonable cost
 Optimize configuration to satisfy design goals.
 Develop best PFA. Hardware configuration best meats PFA algorithm
 Our choice:
 Scintillator based calorimeter
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Calorimeter Configuration
 EM Configuration :
Tungsten-Scintillator Strip
 Large inner radius
 Small Moliere radius
 Fine Granuarity
Distance of g from p0 at r=210cm
O(1) cm segmentation is necessary
 HD CAL: Lead-Scinti. Sandwitch
 Active Sensor:
 Strip/Tile combination
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GLD CAL Configuration
12 sided shape:
EM CAL
HD CAL
Readout cable goes between HD CAL module
to minimize dead space in EM
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Photon Sensor R&D
 Merits of Silicon Photon Pixel Sensor




Work in Magnetic Field
Very compact and can directly mount on the fiber
High gain (~106) with a low bias voltage (25~80V)
Photon counting capability
~1cm
SiPM case:
O(100) pixels,
Each pixel is in
Geiger mode.
# hit pixel
= # input lights
36
>2000 pix
For GLD
37
Status and Plans on Calorimeters
 ECAL large prototype in progress
 Sci-strip type
 HCAL large prototype needs funding!
 SiPM/MPPC promissing and testing in progress
 More PFA study painfully needed
 Optimization for high-energy jets (granularity)
 Scintillator strip design works?
38
Detector Timeline
Accelerator
(2005 end) Acc. Baseline
Configuration Document (BCD)
Detector
Detector R&D report
(2006,3)
“Detector outline documents”
(one for each detector concept)
(2006 end) Acc. Reference
Design Report (RDR)
Detector Concept Report (DCR :
one document)
(~2008) LC site EOI
Collaborations form
~Site selection + 1yr
Global lab selects experiments.
By H.Yamamoto
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Summary
 Detector Outline Document will be released soon. But there are
many issues yet to be studied. Detector Concept Study will
continue further towards DCR.
 Studies of detector technologies are in progress for Vertex
Detector, TPC, and Calorimeter. In all items, regional and interregional cooperation will be strengthened towards detector
LOI/TDR in several years:




Japan-Korea joint studies on Calorimeter
EUDET: TPC and Calorimeter
Calorimeter beam tests in FNAL with CALICE
… more
 Detector R&D needs more funding
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