a maps-based readout of an electromagnetic calorimeter for the ilc nigel watson (birmingham univ.)...
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A MAPS-based readout of an A MAPS-based readout of an electromagnetic calorimeter electromagnetic calorimeter
for the ILCfor the ILC
A MAPS-based readout of an A MAPS-based readout of an electromagnetic calorimeter electromagnetic calorimeter
for the ILCfor the ILC
Nigel Watson
(Birmingham Univ.)
•Motivation•Physics simulations•Sensor simulations•Testing•Summary
For the CALICE MAPS groupJ.P.Crooks, M.M.Stanitzki, K.D.Stefanov, R.Turchetta, M.Tyndel,
E.G.Villani (STFC-RAL)
Y.Mikami, O.D.Miller, V.Rajovic, NKW, J.A.Wilson (Birmingham)J.A.Ballin, P.D.Dauncey, A.-M.Magnan, M.Noy (Imperial)
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Mass (jet1+jet2)
Mass (
jet3
+je
t4)
Mass (
jet3
+je
t4)
Mass (jet1+jet2)
E/E = 60%/EE/E = 60%/E E/E = 30%/EE/E = 30%/E
Equivalent best LEP detector Goal at ILC
Essential to reconstruct jet-jet invariant masses in hadronic
final states, e.g. separation of W+W, Z0Z0, tth, Zhh, H
ILC: high performance ILC: high performance
calorimetrycalorimetry
ILC: high performance ILC: high performance
calorimetrycalorimetry
LEP/SLD: optimal jet reconstruction by energy flow Explicit association of tracks/clusters Replace poor calorimeter measurements with tracker
measurements – no “double counting”
Little benefit from beam energy constraint, cf. LEP
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Shower containment in ECAL, X0 large
Small Rmoliere and X0 – compact and narrow showers
int/X0 large, EM showers early, hadronic showers late
ECAL, HCAL inside coil
Lateral separation of neutral/charged particles/’particle flow’
Strong B field to suppresses large beam-related background in detector
Compact ECAL (cost of coil)
Tungsten passive absorber
Silicon pixel readout, minimal interlayer gaps, stability “Swap-in” alternative to Si diode detector designs, e.g. in LDC, SiD CMOS process, more mainstream:
Industry standard, multiple vendors (schedule, cost) (At least) as performant – ongoing studies Simpler assembly Power consumption larger – but better thermal properties
ECAL design principlesECAL design principlesECAL design principlesECAL design principles
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Basic concept for MAPSBasic concept for MAPSBasic concept for MAPSBasic concept for MAPS
• How small?• EM shower core density at
500GeV is ~100/mm2
• Pixels must be<100100m2
• Our baseline is 5050m2
• Gives ~1012 pixels for ECAL – “Tera-pixel APS”
• How small?• EM shower core density at
500GeV is ~100/mm2
• Pixels must be<100100m2
• Our baseline is 5050m2
• Gives ~1012 pixels for ECAL – “Tera-pixel APS”
• Swap ~0.5x0.5 cm2 Si pads with small pixels• “Small” := at most one particle/pixel• 1-bit ADC/pixel, i.e.
Digital ECALDigital ECAL
Effect of pixel sizeEffect of pixel size
50m
100m
>1 particle/pixel
Incoming photon energy (GeV)
Weig
hte
d n
o.
pix
els
/even
t
SiD 16mm2 area cells
ZOOM
5050 μm2
MAPS pixels
Tracking calorimeter
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Physics simulationPhysics simulationPhysics simulationPhysics simulation0.5 GeVMPV = 3.4 keVσ = 0.8 keV
5 GeVMPV = 3.4 keVσ = 0.8 keV
200 GeVMPV = 3.4 keVσ = 0.8 keV
Geant4 energy of simulated hits
Ehit (keV)
Ehit (keV)
Ehit (keV)
MAPS geometry implemented in Geant4 detector model (Mokka) for LDC detector concept
Peak of MIP Landau stable with energy
Definition of energy: E Npixels
Artefact of MIPS crossing boundaries Correct by clustering algorithm
Optimal threshold (and uniformity/stability) important for binary readout
Threshold (keV)
(E)/
E 20 GeV photons
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
CALICE INMAPS ASIC1CALICE INMAPS ASIC1CALICE INMAPS ASIC1CALICE INMAPS ASIC1
Architecture-specific analogue circuitry
4 diodes Ø 1.8 m
First round, four architectures/chip (common comparator+readout logic)
INMAPS process: deep p-well implant 1 μm thick under electronics n-well, improves charge collection
0.18m feature size
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Physics data rate low – noise dominates
Optimised diode for Signal over noise ratio Worst case scenario
charge collection Collection time
Device level simulationDevice level simulationDevice level simulationDevice level simulation
Signal/noiseSignal/noise
0.9 μm1.8 μm3.6 μm
Distance to diode (charge injection point)
Sig
nal/
Nois
e
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Near future plansNear future plansNear future plansNear future plans
Work ongoing on the set of PCBs holding, controlling and reading the sensor.
Test device-level simulations using laser-based charge diffusion measurements at RAL 1064, 532,355 nm,focusing < 2 μm,
pulse 4ns, 50 Hz repetition, fully automated
Cosmics and source setup, Birmingham and Imperial, respectively.
Potential for beam test at DESY end of 2007
Expand work on physics simulations Test performance of MAPS ECAL in
GLDC and SiD detector concepts Emphasis on re-optimisation of particle
flow algorithms
3 July: 1st sensors delivered to RAL
3 July: 1st sensors delivered to RAL
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
SummarySummarySummarySummary Concept of CMOS MAPS digital ECAL for
ILC Multi-vendors, cost/performance gains
New INMAPS deep p-well process (optimise charge collection)
Four architectures for sensor on first chips, delivered to RAL Jul 2007
Tests of sensor performance, charge diffusion to start in August
Physics benchmark studies with MAPS ECAL to evaluate performance relative to standard analogue Si-W designs, for both SiD and LDC detector concepts
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Backup slides…Backup slides…Backup slides…Backup slides…
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Architectures on ASIC1Architectures on ASIC1Architectures on ASIC1Architectures on ASIC1
Presampler Preshaper
Type dependant area: capacitors, and big resistor or monostable
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Beam background studiesBeam background studiesBeam background studiesBeam background studies Beam-Beam interaction by
GuineaPig
Detector: LDC01sc
2 scenarios studied : 500 GeV baseline, 1 TeV high luminosity
purple = innermost endcap radius500 ns reset time ~ 2‰ inactive pixels
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
The sensor test setupThe sensor test setupThe sensor test setupThe sensor test setup5 dead pixelsfor logic :-hits buffering (SRAM)- time stamp = BX(13 bits)- only part with clock lines.
84
pix
els
42 pixels
Data format 3 + 6 + 13 + 9 = 31 bits per hit
7 * 6 bits patternper row
Row index
1*1 cm² in total2 capacitor arrangements
2 architectures6 million transistors, 28224 pixels
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
•Neighbouring hit:•hit ? Neighbour’s contribution•no hit ? Creation of hit from charge spread only
•All contributions added per pixel
•+ noise σ = 100 eV
Impact of digitisationImpact of digitisationImpact of digitisationImpact of digitisation
E initial : geant4 deposit
•What remains in the cell after charge spread assuming perfect P-well
•+ noise σ = 100 eV, minus dead areas : 5 pixels every 42 pixels in one direction
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Physics data rate low – noise dominates
Optimised diode for Signal over noise ratio Worst case scenario
charge collection Collection time.
Device level simulationDevice level simulationDevice level simulationDevice level simulation
Using Centaurus TCAD for sensor simulation + CADENCE GDS file for pixel description
Signal/noiseCollected charge
0.9 μm1.8 μm3.6 μm
Distance to diodeDistance to diode
EPS'07, 19-Jul-2007Nigel Watson / Birmingham
Digitisation procedureDigitisation procedureDigitisation procedureDigitisation procedure
Geant4 Einit
in 5x5 μm² cells
Sum energy in 50x50 μm² cells
Esum
Apply charge spreadEafter charge spread
Add noise to signal hitswith σ = 100 eV
(1 e- ~ 3 eV 30 e- noise)
+ noise only hits : proba 10-6 ~ 106 hits in the whole detector
BUT in a 1.5*1.5 cm² tower : ~3 hits.
%Einit
%Einit
%Einit %Einit
%Einit
%Einit %Einit
%Einit
Eini
tRegister the position and the
number of hits above threshold
Importance of the charge spread :
initneighbours EE %)80%50(~