ANL R&D Goals
E-flow Optimization Progress
RPC Readout R&D
Summary
* Permanent address – Freiburg University
E-Flow Optimization of the HCAL for a LC E-Flow Optimization of the HCAL for a LC Detector – ANL Status ReportDetector – ANL Status Report
S. Magill, A. Bamberger*, S. Chekanov, G. Drake, S. Kuhlmann,
B. Musgrave, J. Proudfoot, J. Repond, R. Stanek, R. Yoshida
Argonne National Laboratory
LC HCAL R&D Goals at ANL - LC HCAL R&D Goals at ANL - MotivationMotivation
Physics Requirement : separate W, Z using dijet mass in hadronic decay mode (~70% BR)
Detector Goal : measure jets with energy resolution /E ~ 30%/E
Optimize HCAL to be used with ECAL and Tracker in E-flow jet reconstruction –
• Charged particles ~ 60% of jet energy -> Tracker• Photons ~ 25% of jet energy -> ECAL• Neutral Hadrons ~ 15% of jet energy -> HCALCalorimeter challenge : charged/neutral shower separation
requires high granularity, both transverse and longitudinal, to reconstruct showers in 3-D
LC HCAL R&D Goals at ANL – Scope of LC HCAL R&D Goals at ANL – Scope of WorkWork
1) Optimize, in simulation, the design for an HCAL which, when used in an E-flow jet reconstruction algorithm, can reconstruct jets with /E ~ 30%/E.• study absorber type/thickness with JAS, standalone GEANT3
program• tune transverse granularity and longitudinal segmentation in
JAS• test both analog and digital readout techniques• optimize E-flow algorithm
2) Investigate the feasibility of using Resistive Plate Chambers (RPCs) as the active media in the HCAL.• avalanche vs streamer mode• noise reduction, signal optimization, readout schemes
3) Develop electronics readout schemes for the optimized HCAL. • digital vs multi-threshold analog• efficient data compression
How we will optimize HCAL :
Cell size determinationSeparation of charged/neutral clusters in 3-D
Cluster algorithmsE-weighted cell association to clusters (analog readout)Tracking clusterer (digital readout)
Fine tuning of absorber typedensity : W/Pb/U vs SS/Cu and thickness
Analog Readout
Digital
Log10 Cell Size (cm2)
Jet
E R
esolu
tion
(%
x
E)
Towards HCAL Towards HCAL OptimizationOptimization
e+e- ZZ (500 GeV CM)
SD Detector :
ECAL30 layers W(0.25 cm)/Si(0.04 cm)~20 X0, 0.8 I ~5 mm X 5 mm cells
HCAL34 layersSS(2.0 cm)/Scin(1.0 cm)~40 X0, 4 I ~1 cm X 1 cm cells
Modified SD A:
ECAL30 layers W(0.25 cm)/Si(0.04 cm)~20 X0, 0.8 I ~1 cm X 1 cm cells
HCAL60 layersW(0.7 cm)/Scin(1.0 cm)~120 X0, 4.5 I ~1 cm X 1 cm cells
Modified SD B:
ECAL30 layers W(0.25 cm)/Si(0.04 cm)~20 X0, 0.8 I ~1 cm X 1 cm cells
HCAL60 layersW(0.7 cm)/Scin(1.0 cm)~120 X0, 4.5 I ~3 cm X 3 cm cells
Java Analysis Studio (JAS)Java Analysis Studio (JAS)
Soon to come – 5 cm X 5 cm HCAL cells -> ECFA/DESY HCAL
JAS Example – Neutral Particles in CALJAS Example – Neutral Particles in CAL
Charged particles in trackerNeutral particles in CAL
- in ECAL- KL
0, n, nbar in HCAL
Photon AnalysisPhoton Analysis Analog ReadoutAnalog Readout
Analog Readout – perfect Gamma cluster
/mean ~ 15%
Photon Analysis Photon Analysis Digital ReadoutDigital Readout
Digital Readout – perfect cluster
/mean ~ 24%
Digital worse than analog readout
non-linear behaviorfor dense showers
KKLL00 Analysis – SD Detector Analysis – SD Detector
Analog ReadoutAnalog Readout
/mean ~ 30%
Compare to digital
KKLL00 Analysis – SD Detector Analysis – SD Detector
Digital ReadoutDigital Readout
/mean ~ 26%
Average : ~43 MeV/hit
linear behavior forhadron showers
Analog EM + Digital HAD x calibration
KKLL00 Analysis – Modified SD Analysis – Modified SD Analog ReadoutAnalog Readout
SD A (1 cm X 1 cm)
SD B (3 cm X 3 cm)
/mean ~ 26%
/mean ~ 35%
KKLL00 Analysis – Modified SD Analysis – Modified SD Digital ReadoutDigital Readout
SD A (1 cm X 1 cm)
SD B (3 cm X 3 cm)
/mean ~ 20%
/mean ~ 25%
HCAL (only) Digital HCAL (only) Digital ResultsResults
/mean ~ 28%
/mean ~ 28%
/mean ~ 32%
SD
SD A
SD B
1 cm X 1 cm
1 cm X 1 cm
3 cm X 3 cm
E-Flow AlgorithmE-Flow Algorithm
1st step - Track extrapolation thru Cal – substitute for Cal cells in road (core + tuned outlyers) – Cal granularity optimized for separation of charged/neutral clusters
2nd step - Photon finder (use shower shape info)
3rd step - Neutral hadron clusterer
4th step – Jet Algorithm on E-flow objects
or
3rd step - Jet Algorithm on Tracks and Photons
4th step – include remaining Cal cells in jet (cone?)
Systematic Approach : Tracks first (60%), Photons next (25%),Neutral hadrons last (15%)
RPC Readout RPC Readout DevelopmentDevelopment
Using RPC from FNAL (P. Mazur) :• size: 25 x 25 cm2• gas gap 2 mm• glass plates 2 mm thickness• resistive electrodes 40 kOhm/square• pad readout behind the anode electrode• gas: Ar 30% Isob. 8% Freon 62% (a la BELLE)• pad structure of 4x4 cm2, 2x2 cm2, 1x1cm2• coupled to to give configurations
- all pads + frame - all pads- 5(4x4)+2(2x2) cm2 - 4x4+2(2x2) cm2
Chamber Chamber OperationOperation
avalanche mode observed for HV < 8.2 kV, few pC charge
change to streamer mode HV > 8.5 kV few 100pC
streamer mode has multiple streamers as HV increases,charge of a streamer is a slow function of the HV
streamers are seperated in time, but merge at HV > 9.2 kV
efficiency > 95% single rate compatible with
cosmics
Readout of Readout of padspads
size of the pad is varied for finding the spatial extension of the induced charge
effective size has a radius of about 6 cm known to depend on the resistivity of the
HV electrodes, here: 40 kOhm/square measure charge of streamers for events
at readout pad, compare with those taken at a distance of ~ 6 cmCross talk (intergration time here: 100 ns)
Next steps : higher resistivity of electrodes reduces lateral coupling of the pads.
Starting studies of HCAL optimization for E-Flow jet analysis- optimal transverse cell size and longitudinal segmentation- optimal absorber material/thickness- analog vs digital readout
Starting development of E-Flow analysis tools- cluster algorithms for analog/digital modes- separation algorithms for clusters
Studying characteristics of RPC readout for HCAL
SummarySummary