1/9/2003 uta-gem simulation report venkatesh kaushik 1 simulation study of digital hadron...

1/9/2003 UTA-GEM Simulation ReportVenkatesh Kaushik

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Simulation Study of Digital Hadron Calorimeter Using GEM

Venkatesh Kaushik*University of Texas at Arlington

•Introduction•GEM Geometry Implementation in Mokka•GEM Single Pion Studies •Conclusion

*On behalf of the HEP Group at UTA


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Introduction• LC physics topics require

– Distinguish W from Z in two jet final states Good jet mass resolution– Higher Jet energy resolution;– Excellent jet angular resolution

• Energy flow algorithm is one of the solutions– Replace charged track energy with momentum measured in the tracking

system• Requires efficient removal of associated energy cluster Good

position resolution• Higher calorimeter granularity

– Use calorimeter only for neutral particle energies– Best known method for jet energy resolution improvement

• Large number of readout channel will drive up the cost for analogue style energy measurement Digital HCAL

• Tracking calorimeter with high gain sensitive gap

JetJet EE%30~


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UTA Simulation Effort

• S. Habib and VK have been working on this project for their Master’s theses– Mokka geometry database downloaded and installed– Simple GEM geometry implemented– Completed single pion studies using GEM and TESLA-

TDR geometry.• Various software has been packaged and released


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CERN-open-2000-344, A. Sharma

Large amplification

Gas Electron Multiplier (GEM)

• Exploring the possibility of using GEM in hadron calorimetry

• GEM DHCal Progress and Plans, A.White (Session IV, Jan 11, 8:30-10:00)


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Single Pion StudiesGEM and TESLA TDR Geometry

• Single pion events using Mokka particle gun command – Incident energy range: 5 – 150 GeV

• Developed analysis programs to read total energies deposited per pion for each incident energy– Gain of the GEM detector given (3500) as a detector property– EM-HAD relative weighting factor necessary– Mean energy v/s incident pion energies – Energy conversion from the slope of the straight line– Conversion factors are 2.4% (for GEM) and 3.47% (for TDR)

and agree with the computed sampling fraction


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TESLA TDR Geometry

Existing Geometry of Digital Hadron Calorimeter 8 staves each having 5 modules Each module has 40 layers, each layer

with plates of 18 mm of Fe and 6.5 mm of polystyrene scintillator

Hcal hits are collected Polystyrene scintillator, in cells of ~1 cm2

Hcal end-caps are build as 32 side Polyhedrons, with 40 layers inside, each layer with plates of 18 mm of Fe and 6.5 mm of Polystyrene scintillator

Courtesy: Paulo deFrietas

Replace with GEM


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GEM Geometry Implementation Mechanics in Mokka

TDR / Hcal02 Model chosen for modification

Fe-GEM sub-detector instead of the existing Fe-ScintillatorNew driver for the HCal02 sub-detector moduleLocal database connectivity for HCal02 Database downloaded and implemented at UTA Courtesy: Paulo deFrietas


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Double GEM Geometry

0. 0051. 0

Cu

Kapton

ArCO2

G10

0. 005

6.5mm Simple GEM

3.4 mm ArCO2

GEM3.1 mm

Detailed GEM

• Simple GEM uses average density


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Comparison of Detailed and Simple GEM Geometries

Detailed GEM75GeV

• 25.2sec/event for Simple GEM v/s 43.7 sec/event for Detailed GEM• Responses look similar for detailed and simple GEM geometry• Simple GEM sufficient

<E>=0.80 0.007MeV <E>=0.81 0.008MeV

Simple GEM75GeV


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Single Pion Cell Energy Deposit in GEM HCal

• GEM cell energy deposit is functional

• Used for discharge studies


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• Incident pion energy 50 GeV. 2000 events

• Live energy deposit in Ecal and Hcal for TESLA TDR geometry

, Live energy (MeV) , Live energy (MeV)

Live Energy Deposit:TESLA TDR

Mean : 8.6 MeV/event Mean: 2.44 GeV/event

EM HAD

EEM EHAD


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• ELive=EEM+ EHAD, Live energy (MeV) ELive

Mean : 1.92 GeV/event

TOTAL

Live Energy Deposit:TESLA TDR


13CERN GDD group

GEM gains

HV=420V

G=3500


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Live Energy Deposit: GEM

TOTAL• Mean : 4.87 GeV/event

• Two Gaussian Fits

• G = 3500

• ELive=EEM+ GEHAD

, Live energy (GeV) ELive


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EM-HAD Weighting Factor • ELive=EEM+ W GEHAD

• Obtained the relative weight W using two Gaussian fits to EM only v/s HAD 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


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Gaussian Fit to EM and HAD Only

E= 5 GeV


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GEM Relative Weighting

EM

HAD

Relative WeightW = SlopeEM / SlopeHAD= 0.237

SlopeHAD

SlopeEM


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GEM Live Energy before and after Weight factor

Before

After(Pion Energy)/Event (GeV)

# o

f P

ion

s

Live Energy/Event for 50 GeV Pion in Mokka GEM


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Mean Live Vs Incident EnergyMean Energy Vs Incident Energy for GEM

y = 0.024x - 35.878

0

0.5

1

1.5

2

2.5

0 20 40 60 80 100 120

Incident Energy (GeV)

Mea

n E

ner

gy

(GeV

)

Mean Energy (MeV) Vs Incident Energy for TDR

y = 0.0368x - 33.998

0

1

2

3

4

5

6

0 20 40 60 80 100 120 140 160

Incident Energy (GeV)

Me

an

En

erg

y (

Ge

V)

CTDR = 0.038CGEM = 0.024

E = C * ELive


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GEM Measured Energies for 100 GeV Pion

• Limited fit range to 3 for resolution

• Complete fit range for data


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GEM and TESLA TDR Single Pion Resolution

Still about 10% worse than what French colleagues achieved Due to fitting of measured energy distributions

TESLA-TDRGEM


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Conclusions• UTA team has made a significant progress

– Double GEM prototype (see A. White’s talk) functional

• UTA Developed software packages have been handed-over to N. Graf– Pandora-Pythia ASCII HEPEVT output generator interface– Mokka reader– Mokka ROOT analysis– Mokka to JAS

• GEM Simulation effort making good progress– Geometry implementation completed

• Test for simple and detailed geometry shows consistency– Single pion study of GEM response needed a method to

obtain relative gain factor for EM and HAD normalization– Single pion response seems to be consistent with TDR– First glance at resolution seems to be comparable to TDR– Digital study in progress

• Eflow work will come next

1/9/2003 uta-gem simulation report venkatesh kaushik 1 simulation study of digital hadron...

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