UTA GEM DHCAL Simulation

UTA GEM DHCAL Simulation

Jae Yu*

UTA DoE Site VisitNov. 13, 2003

(*On behalf of the UTA team; A. Brandt, K. De, S. Habib, V. Kaushik, J. Li, M. Sosebee, A. White)

•Introduction•GEM Geometry Implementation•Single Pion Study for GEM performances

•GEM Analog Mode•GEM Digital Mode

•Single Pion EFA Studies•Summary

Nov. 13, 2003 Status of DHCAL Simulation, J. Yu

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Introduction• LC physics topics require excellent jet energy and

angular resolutions• Energy flow algorithm is one of the solutions• Large number of readout channel will drive up the cost

for analogue style energy measurement Digital HCAL• Tracking calorimeter with high gain sensitive gap

– GEM is one such detector technology • Simulation effort to understand detector progressed

along with prototype development– Thanks to the support from LCRD and ADR


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UTA GEM Simulation • LC Physics Events: Pandora – Phythia • Use Mokka as the primary tool

– Kept the same detector dimensions as TESLA TDR– Replaced the HCAL scintillation counters with GEM

(18mm SS + 6.5mm GEM, 1cmx1cm cells) • Single Pions used for performance & EFA

studies– 5 – 100 GeV single pions– Analyzed them using ROOT


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TESLA TDR Geometry

Ecal – Electromagnetic Calorimeter Material: W/G10/Si/G10 plates (in yellow)•1mm W absorber plates•0.5 mm thick Si, embeded 2 G10 plates of 0.8 mm each

Hcal – Hadronic CalorimeterMaterial:•18 mm of Fe •6.5 mm of Polystyrene scintillator (in green)


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UTA Double GEM Geometry

3.4 mm ArCO2

GEM3.1 mm

Simple GEMDetailed GEM

0.

00

51

.

0

Cu

Kapton

ArCO2

G10

0.

00

5

6.5mm

Detailed GEM75GeV <E>=0.80 0.007MeV <E>=0.81 0.008MeV

Simple GEM75GeV

25.2sec/event for Simple GEM v/s 43.7 sec/event for Detailed GEM


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Energy Deposit for 10 GeV Pions (GEM)

fEM>=0.85

Remaining Total

fHC>=0.85


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GEM-Digital: Elive vs # of hits for π-


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GEM Cell Occupancies

~85% single hit

~15% >1 hit

~74% single hit

~26% >1 hit

Number of cells with higher number of hits increase w/ E


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N vs Layer

Energy Deposit/Ncells vs Layers for 50 GeV Pions

E vs Layer


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Extraction of of dE/dN


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EM-HAD Relative Weighting Factor • To compensate the response differences

between ECAL and GEM HCAL responses a procedure to normalize them had to be introduced– ELive=EEM+ W gEHAD (g:GEM Intrinsic gain)

– 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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GEM – Relative Weights

Analog

Digital


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GEM-Digital: Live Energy 50 GeV π-


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GEM – Normalized Response

Analog: 2.4%

Digital:2.6%


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Converted energy: 50 GeV π-

Analog

DigitalFits are Landau + Gaussian


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Resolutions

Digital GEM

Analog GEM


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EF Technique

C 2

C 3

C 5

C 7

C 4

C 6

C 1

ij CENormal Calorimetric Method:

p2p3 p5

p7

Energy Flow Method:

nCpE ij

Only susceptible part to Shower statistical fluctuation


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• Charged particle energy subtraction based on track-cluster association is important to EFA

• The algorithm must work well with single particle case• Pions E π- = 7.5 GeV chosen for study• Studied the energy distribution of pions in jet events

• Find the centroid of the shower ( HCAL ) using– Energy weighted method– Hits weighted method– Density weighted method

• Match the extrapolated centroid with TPC last layer hit to get Δ and Δφ distribution

Energy Flow Studies Using π-

TeVsjetsttee 0.1 @ 6


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• Energy Weighted Method

• Hit Weighted Method

• Density Weighted Method

Calorimeter Centroid Determination

n

n

jij

i

1

n

n

jij

i

1

401:

:

1:

i

ilayerinhitsofNumbern

nj

n

jij

n

jijij

i

E

E

1

1

n

jij

n

jijij

i

E

E

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401:

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1:

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nj

n

ijj iji Rd

,1

1

n

jij

n

jijij

i

d

d

1

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Event Displays

E=50 GeV

6 jets

Single


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Neutral particles

Number of charged and Neutral particles

Charged: e, , K

<N>~12 <N>~6


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R of all the particles relative to quark

R flattens out after 0.3


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E weighted vs Numerical Mean)

E = 50 GeV1cm x 1 cm cells

E weighted

<>=-3.1x10-5

=1.1x10-2

Numerical Mean

<>=-1.2x10-3

=2.5x10-2

Analog seems to be better than digital but not by significant factor


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- 7.5 GeV π-

Energy Weighted

Hit Density Weighted

Bug???


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Summary• Made a marked progress thanks to the LCRD and ADR

support• Completed single GEM DHCAL performance studies

– Initial study documented in Habib’s MS thesis– More detailed and refined study being completed by Kaushik– Analog resolution seems to be worse compared to other detector

technology due to large fluctuation in initial ionization electrons– Digital, however, performance is comparable to other analog

technologies• Released our Pandora – Phythia ASCII and other analysis

packages to LC software group per their request


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• EFA studies in progress– Study track – cluster association and energy subtraction using

single pion Three methods being investigated– Study typical distance between charged particles within the jet– Determine necessary resolving power for realistic situation

• Prepare for larger scale prototype, cosmic ray stack and TB simulation

• Development of analysis software• Continued and increased support is critical to make the next

quantum jump

Documents

UTA GEM DHCAL Simulation