Construct two layers of hadron calorimeter and test

Makoto Harada

High Energy Physics Laboratory

Faculty of Physics

Department of Science

Shinshu University

The purpose of this study

I constructed two layers of hadron calorimeter and

tried to detect point where cosmic

rays passed.

mmmm 1010

I tested my hadron calorimeter by using Geant4

simulation.

Improve detection accuracy and energy resolution of

ILD hadron calorimeter

Hadron calorimeter

A detector which causes hadron shower to hadron

and measures its energy.

total track length of all generated particles

measuring total track length → measuring incidence particle energy

It is essential to detect the point where a particle passed accurately.

incidence particle energy

Two layers of hadron calorimeter

A particle

mm180

mm11

Absorber ： Tungsten alloy (Thickness 3.5 mm )

Gap : Scintillators (Thickness 2.0 mm )

mm180

Scintillators are divided into 18 bars.

Scintillator bars of 1st and 2nd layer are orthogonal.

A particle

(point passed by a particle)

These two scintillators radiate light.

mm10

mm180

A particle passed common square area

of these two scintillators.

mmmm 1010

Reflector Scintillator

・ prevent light from escaping out of scintillators

・ get independent signal from each scintillators

→ wrap each scintillators in a reflector

I made 36 scintillators wrapped in a reflector

Scintillation light

using fiberno fiber

gathered by wave length shift fiber

detected by MPPC MPPC ・・・ a new type of photodetector

・ small size and reasonable price

・ photocounting efficiency

・ tolerance to magnetic field

MPPC

Constructing hadron calorimeter

Absorber side Gap side

Structure of absorber is tungsten alloy plates

Structure of gap is 18 scintillators

magnification

ADC distribution of MPPC (use )Sr90

d

..1 ep ..2 ep

..3 ep

..0 ep

Cou

nt o

f eve

nts

ADC Count )25.0( pC

： the difference between peak and peak d ..1 ep..0 ep

..5.0 ep

Average Photo Electron ( )

→ divided into the average of ADC count more than ..5.0 epd..ep

36 scintillators efficiency test (use )Sr90A

vera

ge P

hoto

Ele

ctro

n (

p.e.

)

Scintillator number

Average : Standard deviation :..53.7 ep ..56.0 ep

No.1 ~ 18 scintillator → 1st layer No.19 ~ 36 scintillator → 2nd layer

I detected scintillation light using MPPCs.

Then, I made ADC distribution about each MPPCs.

two layers of hadron

calorimeter

I set two PMTs up and down hadron calorimeter and used them as trigger.

Scintillator of trigger 1

Scintillator of trigger 2

Experiment with cosmic raysTwo layers of hadron calorimeterA side view

The relation between trigger scintillators and hadron calorimeter

① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫ ⑬ ⑭ ⑮ ⑯ ⑰ ⑱

①②③④⑤⑥⑦⑧⑨⑩⑪⑫⑬⑭⑮⑯⑰⑱

1st layer

2nd layer

Trigger 1

Trigger 2

When cosmic rays pass this common area, the ADC gate is opened.

⑩ ⑪ ⑫ ⑬ ⑭ ⑮ ⑯ ⑰ ⑱

⑩⑪⑫⑬⑭⑮⑯⑰⑱

① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨

①②

④⑤⑥⑦⑧⑨

③

I can get data from No.1 ~ 9scintilator ofeach layers.

2nd layer

1st layer

Curtain box

tillatorScin MPPC

AMPASD BufferASD

2Trigger

natorDiscrimi eCoincidenc

ADCCircuit diagram

1Trigger

tillatorScin MPPC

ADC

AMPASDBufferASD

R Circuiteadout

R Circuiteadout

RayCosmic

Results of experiment

I measured cosmic rays 20000 times.

I changed ADC count into photo electron.

1st layer

1st 2nd 3rd 4th 5th 6th 7th 8th 9th

16.0 24.6

93.6

This is an example of one of the events.

This data shows point where a cosmic ray passed.mmmm 1010

20.0 25.0 10.0 09.0 08.0 14.0 04.0

07.0 04.0 04.0 06.008.0 01.0 16.0 01.02nd layer

P.E. distribution

ElectronPhoto

P.E. distribution (Landau fit)

the peak of Landau fit : ..08.7 ep

Cou

nt o

f eve

nts

Sum of events about scintillators of 2nd layerSum of events about scintillators of 1st layerHistogram of point passed by cosmic rays

Detection rate : %0.61

Scintillator number of 2nd layer

Scintillator number of 1st layer

Cou

nt o

f ev

ents

Geant4 simulation

Hadron calorimeter planned to be used in ILD

・ Absorber ： Pure iron （ Thickness ,Density ）

・ Gap ： Scintillator （ Thickness ）

・ Number of layers ：

・ Size ： （ To compare my hadron calorimeter ）

mm20 3/874.7 cmg

mm2

mmmm 180180 48

I researched energy resolution through simulation that

shoots , and particles for this

hadron calorimeter.

GeV10 GeV30 GeV80

Results of simulation

I require my hadron calorimeter to satisfy this resolution

I research how many layers will need by using Genat4 simulation.

80

58.077.27 31.048.16 25.016.13

Energy 3010

Resolution

)(GeV

)%(

My Hcal : 100 layers

Comparing resolution

ILD Hcal ： 48 layers

absorber ： pure iron （ thickness ）

gap ： scintillator (thickness ）

mm0.20mm0.2

80

58.077.27 31.048.16 25.016.13

Energy 3010

Resolution

)(GeV

)%(

80

45.009.19 39.012.10 48.050.11

Energy 3010

Resolution

)(GeV

)%(

absorber ： tungsten alloy （ thickness ）

gap ： scintillator (thickness ）

mm5.3mm0.2

Conclusion

My hadron calorimeter needs 100 layers to satisfy

energy resolution of ILD hadron calorimeter.

（ thickness of hadron calorimeter will be half ）

Using cross scintillators, I succeeded in detecting the

point where cosmic rays had passed.

My hadron calorimeter showed 7 photo electron.

mmmm 1010

I constructed two layers of hadron calorimeter.

Tasks

I Investigate how much photo electron increases

by using Scintillators which are in thickness.mm3

I make a histogram of point passed by particles

through simulation that shoots them for hadron

calorimeter whose each gap are divided into 18 bars.