Transcript Calorimeter R & D for Linear Collider

Calorimeter R & D for Linear Collider
Naba K Mondal
TIFR, Mumbai
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
LC Calorimeter
• Goal:
– Measure the Energy and mass of final state particles as
precisely as possible.
– Many final state will contain particles escaping the
detector. Need to measure missing energy as
accurately as possible.
• Energy resolution of Calorimeter :
–
E  A E
– For most of the existing and planned detectors A ~.6-.7
– We need to achieve a value of 0.3 for LC calorimeter
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
LC Calorimeter
E  0.3 E
• Why we need
Few Examples
• Measurement of Longitudinal coupling of W
boson
– Need to distinguish between nnWW & nnZZ final
states.
60%
E
30%
E
W/Z identification
by mass reconstruction
 in 4 jets
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
LC Calorimeter
• Measurement of Higgs Self coupling in ZHH
final state:
– For a luminosity of 1 ab-1 , the signal is expected to
be at 3σ for α=0.60 while the signal goes to 6σ for
α=0.30
• Measurement of Higgs to W boson branching
ratios
– The expected precision on BR(H→WW) downgrade by
22% when passing from α=0.30 to α=0.60.
– It is equivalent to a loss of 45% of the luminosity.
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
How to reach E  0.3 E?
• For a 500 GeV e+e- collider– consider the
process e+e- ---> ZZ consider the hadronic Z
decay:
– Energy sharing
» Charged pions : ~60%
» Photons
: ~25-30%
» Neutral hadrons: ~10-12%
» Neutrinos
:~small
resolution
Use tracker in a magnetic field for
Measuring charge particle energy.
E.M. Calorimeter for photon energy
measurment.
HCAL for measuring the energy of neutral
Hadrons only.
Tracker better <= 70 GeV/c
Energy flow Algorithem
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Design Optimisation for Energy Flow
Challenges:
Charged/neutral shower seperation requires
High granularity in both longitudinal and
Transverse direction to reconstruct showers
Due to individual particles in 3D.
Software to recognise tracks and clusters.
Calorimeter has to be far enough from the
Interaction point.
Should have small radiation length, small
interaction length and a matched readout
granularity.
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Talks on Calorimetry
• Study of Scintillator based EM Calorimeter
– H. Matsunaga
• Hardware aspects of ECAl & HCAL opions from
ALCPG
– M.Oreglia
• Simulation and Particle flow Algorithems for LC
detectors
– D.Chahraborty
• Detector R & D Opportunities for a LC at
Fermilab
– Slawomir Tkaczyk
• Development of RPC for INO
– B.Satyanarayana
• Heavy Ion detector R & D in India
– Y.P.Viyogi
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
ALCPG Calorimetry:
Hardware Aspects of ECAL and HCAL Options
• ECAL R/D
–
–
–
–
Si-W
Scintillator-W
Hybrids
crystals
• HCAL R/D
– Scintillator
– RPC
– GEM
Si-W design (SLAC/Oregon) =>
cost and minimal RM require
compromise on E resolution by
minimizing Si area (30 layers)
and (Si thickness (300 mm))
Scint-W design (Colorado) =>
inexpensive, more samples – but
poor granularity and larger RM
Si-W-Scint. Hybrid (Kansas, KState)=> thin Scint. layers,
cheaper, more samples (incl. Si),
retain granularity, keep RM small
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
ALCPG Calorimetry:
Software and Simulation aspects
STDHEP
(pythia/pandora or particle gun)
GISMO (SLAC)
EGS, GEISHA
xml geom. input
Projective only
LCDG4(NIU)
G4, xml geom. input,
Handles non-proj
geometries
Mokka (LLR)
LCDMokka (DESY/
SLAC): G4, MySQL
or xml geom. input
Sio/lcio output for reco/analysis with
JAS/Root/indep. AIDA-compliant code
N.K.Mondal, Calorimeter Summary,
+ several standalone simulation
programs
17th Dec, 2002, ACFA Workshop
Si-W geometry
6-inch f
hexagonal
Si wafers
DC coupled
Read out 1000 pads
power challenge
• can dynamic
range be realized?
(0.1-2000 MIP)
•
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Transverse
segmentation
of 5mm x 5
mm possible
Scint-W Sampling Calorimeter
Offset helps – but position
resolution at low energy ??
Considering pixels of 50mm x
50 mm area to allow 1mm fiber
curving
1.75 mm W; 2mm Sc ; 1mm gap
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Hybrid Si-W-Scint. Calorimeter
HY75
HY135
HY42
• 1.4mm W plates • 0.778mm W plates
• 15 layers Si
• 15 layers Si
• 60 layers of
• 120 layers of 1mm
1.5mm Scint.
Sc
• 4 layers ganged • 8 layers ganged
(30 pe/mip) ( if
(40 pe/mip)
5pe/mip/mm)
• 15 super-layers
• 15 super-layers each
with mip-detection
E res :
Moliere radius :
• 2.5 mm W plates
• 14 layers Si
• 28 layers of 2 mm
Sc
• 2 layers ganged
(20 pe/mip)
• 14 super-layers
10.4%/E
7.7%/E
14.3%/E
19.3 mm
21.4 mm
16.5 mm
33% of the
Silicon
cost
(SDMar01 30X0 W : 15.4%/E, 15.5 mm with 0.1 mm range cut)
Smallest shower size in SD, but HY42 achieves almost
the same E resolution with a slightly larger shower for
33% of the silicon cost
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Fine granularity ECAL for the GLC calorimeter
group

Currently studying fine granularity ECAL with Pb/Sci
sampling technique
 examine “particle flow” analysis capability

Baseline design : tile/fiber ECAL

Option design : strip-array ECAL

Shower-max detector with scinti-strips

 4cmx4cmx1mm-Sci + 4mm-thick Pb
 1cmx20cmx2mm-Sci + 4mm-thick Pb
 Conventional WLS readout
 Directly-attached APD readout
Require multi-channel photon sensors operational in magnetic
field
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Test beams for new ECAL design

2002 : T517 at KEK (e/m/p, 1-4 GeV)


2003 : test at DESY (e, 1-6 GeV)


tile/fiber ECAL, strip-array ECAL, scinti-strip SHmax
scinti-strip SHmax
2004 : T545 at KEK (e/m/p, 1-4 GeV)


tile/fiber ECAL, strip-array ECAL, scinti-strip SHmax
probably the last opportunity for KEK PS beamline
Summary,
Setup of N.K.Mondal,
T517 testCalorimeter
beam measurement
17th Dec, 2002, ACFA Workshop
Energy resolution
Test beam
GEANT3 simulation
w/o photo statistics
If photo statistics is taken into account, beam
test results are consistent
with
simulation
N.K.Mondal, Calorimeter
Summary,

17th Dec, 2002, ACFA Workshop
Linearity
 Linearity : < 3.5%
 < 1% above 2GeV
 deviation at 1GeV :
due to material in
front of ECAL ?
In good agreement with
simulation

N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Spatial resolution
4GeV electron event :
Fitted to Gaussian
Position resolution
for 4GeV electron
s =2.0mm
around shower max
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Angle measurement
 Incident angle : 0 ~ 3 degree
 Offset due to mis-alignment ?
 Ignoring offset, angles are
correctly measured within errors
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Readout of scinti-strip
Strip-size : 20cm x 1cm
x 1cm

 Conventional readout :
WLS + clear fiber to
 MA-PMTs (tested)
 HPDs (2004)
 Directly-attached APDs
on scinti-strip (tested)
 SiPMs directly on WLS
(2004)
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Photon sensors

Multi-pixel Hybrid Photodiode (HPD)
 DEP-HPD used for CMS-HCAL
 We have tested Hamamatsu 64 pixels
HAPD
 Gain = 6 x 104 (good)
 Commercially not yet available

Electron-bombarded CCD (EBCCD)
 Suitable for fiber readout
～400 fibers/device possible
 Sensitivity to single-photon
 Gain is low (< 1000)
 No timing information

Will test them with SHmax in 2004 test
beam
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Photon sensors (cont.)

SiPM
 Micro-APD cells operated in Geiger
mode
 1ch/device, compact, cheap (a few
$/device)
 High gain (~106), but significant
noise rate
 Can be directly attached to WLS
fiber
 Having only one SiPM in Japan, but
expect more from DESY
 Test in 2004 beam test ?
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
HCAL R & D
Optimize application of Energy Flow Algorithms
Separation of different components of jets
Extremely fine segmentation of readout
Readout pads of order of 1 cm2
Layer-by-layer readout
Readout
Digital (1 bit resolution)
Semi-digital (say 2 bit resolution)
Energy resolution preserved in MC simulation studies
Challenges
Develop active medium with required granularity in
readout
Reduce cost of electronic readout to O($1/channel)
Intermediate goal
Construction of 1 m3 prototype section
400,000 readout channels
Candidate for active element
Scintillator, Gas Electron Multipliers (GEMs), Resistive Plate Chambers
(RPCs)
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Scintillator DHCAL
Concept
Northern Illinois University
Scintillator thickness 5 mm
Hexagons of 9.4 cm2 area
Trade-off segmentation with readout resolution
Considering 2 – bit readout (= 3 thresholds)
Non-projective geometry
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
GEM DHCAL
University of Texas at Arlington
Concept
Gas volume for
ionization
GEM foils for
multiplication
→ perforated
Pads for signal pickup
9 channel GEM prototype
using electronics developed
for silicon readout (FNAL)
32 channel boards
3 mm gas gap
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Technology/Design simulations: GEM Digital HCal
(UTA)
• Replaced scintillator with
GEM’s – in Tesla TDR
(Mokka)
• Full & mixture
approximation compared
• Single pion studies to
understand response and
resolution
• Analog vs Digital
comparisons
3.4 mm
ArCO2
3.1 mm
GEM
ArCO2
0.
00
6.5mm
51
.
0.
0
00
5
Cu
Kapton
G10
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
GEM HCAL : Analog vs. Digital
• ELive=SEEM+ W SGEHCAL
• Obtained the relative weight W using two Gaussian fits to EM only vs
HCAL only events
• Perform linear fit to mean values as a function of incident pion energy
• Extract ratio of the slopes  Weight factor W
• E = C* ELive
Analog
Digital
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
GEM DHCal: response & E resolution
• Single charged pions
• 1 cm2 cells in HCal
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
RPC DHCAL
Argonne, Boston, Chicago, FNAL
Major effort to:
• prove reliable operation
• vindicate simulation work
• build cubic meter prototype for 2005
Mylar
Pick-up pads
Graphite
Signal
HV
Gas
Resistive plates
Both groups agree
Glass as resistive plates (NO permanent ageing ever observed)
Work in avalanche mode (reduced cross talk, higher rate capability)
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
US chamber tests
Two gas gaps of 0.64 mm each
Gas Freon:Argon:Isobutane = 62:30:8 (in the past)
Freon:Isobutane: SF6 = 94.5:5:0.5 (now)
Readout pads of 1 cm2
High efficiency, wide HV plateau
Little charge outside pad hit
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
HCal: gas vs. scintillator
Needs revision with current algorithms
RPC
Scint.
2
E  r
Digital:   ri
E
N
This is not a measure of ability to separate showers in a jet
Analog:
2
i
i
i
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
DHCal: Density-weighted Clustering
(NIU)
• Density-based clustering
in both ECal and HCal
di = k S (1/Rij)
• Clusters matched to tracks
replaced by their
generated p
• For ECal clusters, use
energy of assoc. cells
• For HCal clusters, use nHit
based E estimate
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Analog vs Digital Energy Resolution
GEANT 4 Simulation of SD Detector (5 GeV p+)
-> sum of ECAL and HCAL analog signals - Analog
-> number of hits with 7 MeV threshold in HCAL - Digital
Analog
Landau tails
+ path length
fluctuations
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Digital
Gaussian
Single 10 GeV
p+: event display comparison
Blue: density = 1
Red: density = 2,3
Green: density > 3
Energy weighted
Density weighted
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
RPC R & D work in India
Looks a good candidate for
Digital Calorimetry
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
PMD for Calorimeter active element ?
STAR & ALICE
•WA93 (S + Au, 200AGeV) :
8000 pads covering 3m2
•WA98 (Pb + Pb, 158 AGeV):
53000 pads covering 21m2
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop
Summary
• Calorimetry is no longer the job of Calorimeter
alone.
• Need global collaboration among all sub
detectors.
• Need to define a model detector to check how
such a collaboration will work effectively.
N.K.Mondal, Calorimeter Summary,
17th Dec, 2002, ACFA Workshop