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