Study of Digital Hadron Calorimeter

Tohru TakeshitaShinshu Univ.March 2006

Linear collider physicsHadron Calorimeter at LCdigital Hadron calorimeter

based on Geant4.6.2

Linear Collider Physics clean but narrow jets final state

TPCECAL

HCAL

e+e- " qq@350GeV

Particle Flow

charged energy

neutral hadron energy

photon energy

energy distrubution : one entry for each energy per event

Energy (GeV)

• Tracker : charged 65% in a jet

• ECAL : photon 25 % in a jet

• HCAL : neutral hadron 10% in a jet

e + e- " WW

ECM = 250GeV

Particle Flow cont.

1cm3

HCAL TrackerECAL

clustring,separation,

andmatching

need fine granularity

in 3-Dim.

digital HCAL

• ~1cm3 granularity for PF in LC

• HCAL of ~100M channels

• need to reduce cost of electronics

• digital read out = ON/OFF at 1cm3 = 1bit read out

• Hadron interaction= EM shower +pure hadronic int.

digital HCAL simulation Test detector : 1m x 1m x 1m of 100 channels3

A layer of 8mm Pb + 2mm scintillator (1cm )2

1m 1m

1m

digital HCAL simulation total hit/energy distribution

cell_hits0 20 40 60 80 100 120 140 160 180 200

0

100

200

300

400

500

600

-!Lead/Sci 4GeV no_cut-cell

Entries 9999Mean 102.3RMS 25.19

/ ndf 2" 181.2 / 44Constant 7.8± 640.4

Mean 0.3± 102.9 Sigma 0.17± 24.46

-!Lead/Sci 4GeV

MeV0 20 40 60 80 100 120 140 160 180 200

0

100

200

300

400

500

-!Lead/Sci 4GeV no_cut-etot

Entries 9999Mean 110.6RMS 30.35

/ ndf 2" 420.9 / 43Constant 6.9± 528.3

Mean 0.3± 110 Sigma 0.23± 28.39

-!Lead/Sci 4GeV

cell_hits0 20 40 60 80 100 120 140 160 180 200

0

100

200

300

400

500

600

700

-!Lead/Sci 4GeV cut<10ns-cell

Entries 9999Mean 85.14RMS 23.82

/ ndf 2" 244.6 / 43Constant 8.4± 678

Mean 0.26± 85.66 Sigma 0.17± 22.96

-!Lead/Sci 4GeV

MeV0 20 40 60 80 100 120 140 160 180 200

0

100

200

300

400

500

600

-!Lead/Sci 4GeV cut<10ns-etot

Entries 9999Mean 103.3RMS 29.86

/ ndf 2" 583.5 / 43Constant 7.4± 558.5

Mean 0.3± 102 Sigma 0.22± 26.55

-!Lead/Sci 4GeV

digital analog

mean=103hitsigma=24hit

mean=110MeVsigma=28MeV

0.1Mip threshold4GeV pions

Gaussian

digital HCAL simulation linearity for pions

analog : perfect

digital : not badlinearity for electrons

digital

0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100

Linarity for pionsHCAL-8pb2sc-mth>0.1mip

digital hitsanalog MeV

digi

tal (

hit)

/ana

log(

MeV

)

E(GeV)

digital HCAL simulation 50GeV pi-

Entries 1461Mean 893.8RMS 191.6

/ ndf 2! 24.14 / 37Constant 1.71± 43.29 Mean 4.1± 953.2 Sigma 4.4± 113.9

Nhit0 200 400 600 800 1000 1200 1400

0

10

20

30

40

50

50GeV pi-Entries 1461Mean 893.8RMS 191.6

/ ndf 2! 24.14 / 37Constant 1.71± 43.29 Mean 4.1± 953.2 Sigma 4.4± 113.9

Lead/Sci 100GeV pi-Entries 6175Mean 1504RMS 410.2

/ ndf 2! 64.4 / 23Constant 4.4± 199.2 Mean 5.9± 1705 Sigma 7.8± 240.9

Nhit0 500 1000 1500 2000 2500

0

20

40

60

80

100

120

140

160

180

200

220

100GeV pi-Entries 6175Mean 1504RMS 410.2

/ ndf 2! 64.4 / 23Constant 4.4± 199.2 Mean 5.9± 1705 Sigma 7.8± 240.9

Lead/Sci

50GeV pi-

Entries 1461Mean 1320RMS 159.8

/ ndf 2! 18.07 / 18Constant 4.0± 106.5

Mean 4.0± 1335 Sigma 3.8± 127.3

MeV800 1000 1200 1400 1600 1800 2000

0

20

40

60

80

100

120

50GeV pi-

Entries 1461Mean 1320RMS 159.8

/ ndf 2! 18.07 / 18Constant 4.0± 106.5

Mean 4.0± 1335 Sigma 3.8± 127.3

Lead/Sci 100GeV pi-

Entries 6175Mean 2624RMS 246.3

/ ndf 2! 63.16 / 54Constant 2.6± 133.7

Mean 3.8± 2645 Sigma 4.0± 223.5

MeV2000 2200 2400 2600 2800 3000 3200 34000

20

40

60

80

100

120

140

100GeV pi-

Entries 6175Mean 2624RMS 246.3

/ ndf 2! 63.16 / 54Constant 2.6± 133.7

Mean 3.8± 2645 Sigma 4.0± 223.5

Lead/Sci

analog

digital

50GeV 100GeVenergy distribution

digital HCAL simulation • analog vs digital

analog

digital

100GeV pion

100GeV

50GeV

0.5mip-th

digital HCAL simulation energy resolution for pions

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1

energy resolution for pions HCAL-8pb2sc-mth>0.1mip

analog-resolutiondigital resolution =sig/digihits

ener

gy resolution

1/sqrt(E)

digitalanalog

digital HCAL simulation segmentation size

1/sqrt(E)

resolutionlinearity

E(GeV)Eth=2mip Eth=0.5mip

0 0.1 0.2 0.3 0.4 0.5 0.6 0.70

5

10

15

20

25

30

35

Analog

Digital

Semi-Digital

Real Data

)-1/2

(GeVE1/

/E(%)

E!

semi(2bits)-digital HCAL • 0.5MIP < EnergyDeposit ≤ 10MIP = 1 hit• 10MIP < EnergyDeposit ≤ 100MIP = 10 hits• 100MIP < EnergyDeposit= 100 hits

σ/E

[%

]

1/√E [GeV-1]

σ/E

[%

]

1/√E [GeV-1]

resolution resolution

Jet energy resolution by DHCAL

HCAL1cm x 1cm segmentation

e+e- " qq@350GeV

500GeV Digital

Z Digi

perfect PF

hardware approach toward DHCAL

• scintillator strips

• homogeneous in strip direction

• to reduce cost

• long strip <> multiple hits in a strip

• photon sensors in strong magnetic field

• MPPC

1cm MPPCWLSF

scintillator strip DHCAL

MPPC R/O

Single pion

0.1

1

10

100

1000

0 20 40 60 80 100z position ( cm )

Hit

tim

e (

ns

)

pi-

4GeV

緑 : ニュートロンのヒット(by G4Track Information)

Z

シンチでトラックから離れたヒットはニュートロン散乱に起因する。

5ns

Sci vs Gas

Pb/Sci

scintillator strip DHCALneutron sesitive

0.1

1

10

100

1000

104

0 20 40 60 80 100

a pion interaction in HCAL layers

time (ns)

Z layer

charged

neutron

0

50

100

150

200

1 10 100 1000

time-cut for pi-4GeV

E(scinti) (MeV)

time cut (ns)

no cut

total energy measured (MeV)

total hits

Pb8+sci2mm

20%

MPPC developmentsemiconductor pixel photon sensor with Geiger or Limited Geiger Mode

2µm

a pixel E (V/cm)

1 10 10 102 4 6

2µm

summary• Digital Hadron Calorimeter investigated

• single particle responses are tested

• pure digital (1bit) HCAL is not sufficient

• semi-digital (2bit) HCAL seems to give similar to analog CAL

• Hardware trial is underway

• test is needed with analog read out and simulate digital case

digital HCAL simulation threshold effect

Log(threshold)

0.1mip

AnalogAnalog vsvs Digital Energy ResolutionDigital Energy Resolution

GEANT 4 Simulation of SD Detector (5 GeV !+)

-> sum of ECAL and HCAL analog signals - Analog-> number of hits with 10 MeV threshold in HCAL - Digital

GaussianLandau Tails+ path length

DigitalAnalog

E (GeV) Number of Hits

"/mean ~22% "/mean ~19%

US-digitalHCAL (US) : RPC Digital-HCAL, PFAAnalog/Digital Response for HadronsAnalog/Digital Response for Hadrons

Showers in a sampling calorimeters are characterized by their spatialdevelopment in terms of “track length” :

Track Length (T) = sum of tracks of all charged particles in a shower – Analogsampling calorimeters sum energy, Digital sampling calorimeters sum hits

T ! E (particle energy) – what about spread in energy?

NhitEmeas

Total Energy SumTotal Energy Sum –– Tracks + Photons + NeutralsTracks + Photons + NeutralsG4v6.1

2 Gaussian fit :mean = 83 GeV! = 7.8 GeV

Poor hadron showerreconstruction with tubes– more sophisticatedapproach

mean = 87 GeV!= 4.7 GeV

Good hadron showerreconstruction

After tuning, very similar resultsv = 3.8GeV (neutrals) 5 1.2 (c)

5GeV r

e + e- " Z " qq