Emulsion Detector for Future Neutrino Research

Possibility of the Technology

NAKAMURA M. (NAGOYA Univ.)

CONTENTS

• Emulsion Detector Overview

• New Study. Emulsion Spectrometer

Emulsion in Magnetic field

• Expected scanning power in near future

Cross sectional view of an emulsion layer

30grains/100mgrain diameter ~ 0.6m

Ag grain after development

dx

= 0.06m

Compton Electron

Fog

M.I.P. Track

100m

M.I.P. Track

Intrinsic position resolution

One Emulsion Layer = vector chamber with 60nm position resolution

& ~1mrad Angular resolution (100micron layer)

Achievement in OPERA R&D

• Nuclear Emulsion Films

Suited for Mass production ~ 100,000m2

Uniform quality

Refresh function　　 R&D by

Nagoya Univ. & Fujifilm

• Fast Scanning systems

in Japan & Europe

125mm

100mm

Refresh

Cosmic-rays

Emulsion film accumulates all signals during its live time

:No dead time.

Compton electrons by γ rays of natural radio activity

Before Refresh After Refresh

We can reset the accumulated images by Refreshing.

Before use or re-use

OPERA ECC Brick

１０ｃｍ

１２．５ｃｍ8cm

8kg：　 Portable Unit for 2~10kton detectors

Tau detection :

DONUT -> OPERA

Topological decay detection:

Kinematical analysis: Momentum measurement by Multiple Coulomb Scatterings (or Emulsion Spectrometer) Electron ID by shower detection Particle ID by dE/dX measurement

Decay search

τ

Fe

film

dE/dX measurement

Pb Film

P=1.2GeV/c

Hadron+

@KEK/PS

dE/dX

dE/dX = measurement

~number of grains

P

dE/dX measurement : TEST exp at KEK0.4 GeV/c 0.5 GeV/c 0.6 GeV/c

0.74 GeV/c 0.87 GeV/c 1.14 GeV/c 2.0 GeV/c

P P P

PP

P

π π π

π π π

D

D D D D

P&π

Entry 1610 tracks Entry 1345 tracks Entry 1175 tracks Entry 1206 tracks

Entry 996 tracks Entry 1310 tracks Entry 1278 tracks

• Using only 5 ~ 6 films.• VPH, measured by the system, is ~propotional to dE/dX.

VPH

P

π

P andπ

Using 5 ~ 6 films.VPH, measured by the system, is ~propotional to dE/dX. Error bar is 1σof the distribution. At 2 GeV/c , proton and pion are not separated in 5 or 6 OPERA films.VPH of proton below 0.6GeV/c is saturated.

Particle ID by dE/dx Measurement

K

dE/dx(MeV ・ cm2/g)

Momentum(GeV/c)

VPH

e

KEK Beam Test Preliminary

50GeV electrons + muons

Electron ID

Test Exp. @ CERN

Electron energy measurement

MC Data

)(E

4.0~

GeV

@ a few GeVEnergy determination by calorimetric method( in study)

Test exp. @ CERN

Emulsion in Magnetic Field

• Charge Sign determination + increase sensitivity + increase BG-rejection power

o scanning load (mention later) o cost??

• We have experience in CHORUS/ET(Emulsion Tracker)

Structure for MC study

Stainless steel or Lead Film

Air Gap

DONUT/OPERA type target + Emulsion spectrometer

B

~ 3Xo ~10Xo

Assumption: accuracy of film by film alignment =10 micron (conservative).(Ex. 20mm gap structure gives 0.5mrad angular resolution.)

mu

Charge determination (0.5T)　MC

P(GeV/ c) Eff. 20mm Eff. 30mm1 99.93% 99.96%2 99.95% 99.97%3 99.94% 99.67%4 99.90% 99.98%5 99.83% 99.96%6 99.58% 99.97%7 98.98% 99.97%8 97.97% 99.96%9 96.78% 99.97%

10 95.32% 99.95%

10mm Gap

20mm Gap

>=30mm Gap

Momentum resolution(0.5T)　MC

10mm Gap

20mm Gap

30mm Gap

40mm Gap

50mm Gap

P(GeV/ c) Eff. 20mm Eff. 30mm1 99.980% 99.994%2 99.983% 99.993%3 99.979% 99.993%4 99.981% 99.992%5 99.973% 99.998%6 99.978% 99.996%7 99.981% 99.994%8 99.976% 99.990%9 99.966% 99.995%

10 99.947% 99.994%

Charge determination (1.0T)　MC

10mm Gap

>=20mm Gap

Momentum resolution(1.0T)　MC

10mm Gap

20mm Gap

30mm Gap

40mm Gap50mm Gap

Summary of the MC study• Emulsion Spectrometer ( B 0.5T,Gap > 20mm, ≧

Total Length~10cm) has power to determine sign & momentum efficiently.

• Further MC study: Investigate the Possibility to open the sensitivity

for hadronic and electric decay mode. Sensitivity >~ x 3 (like OPERA)

• Technological R&D : Unique track connection How to keep air gap Test exp.

Emulsion Film Read-out

Emulsion Readout History

• E531, E653, etc . (~1994) – Semi-automatic scanning

• CHORUS phase I– Track selector, New TS (1994~)

• DONUT, CHORUS phase II– UTS (1998~) Net scan (angle: |<0.4).

• OPERA

Automatic Automatic ScanningScanning

Bottle necks in the Read-out System

Speed of Image Data taking

Movement of Z Stage

Field of View :

Objective Lens

Movement of X-Y stage

Overcome the Bottle necks

Stage moves at constant velocity

Synchronized motion to cancel relative velo.

Ultra High Speed Imager with Real Time processing

• Ultra High Speed Imager– 120 fps -> 3000 fps

• Image taking by follow shot– X-Y stage : Non-stop – Objective lens: Driven by piezo electr

ic devices （ fres>2kHz ） .

• Enlarging size of Field of View– Effective FOV: 100m×100m-> 140m×140m

1cm2/h -> 60cm2/h

SUTS + Old stage

0.008

0.25

3

60

0.001

0.01

0.1

1

10

100

TS(TTL) NTS(CPLD) UTS(FPGA) S-UTS

Scanning System Historyviews/sec(1view=120×90 m2)

Evolution of the Scanning Power

Our code name (device technology)

CHORUS DONUT OPERA

Expected evolution of the Scanning Power in near future

• Enlarge a Field of View × (1.25)2 reduce objective mag. × 50 -> × 40

• Speed up Image data taking ×4 Ultra High Speed Camera 3kfps->12kfps.

400cm2/hours/system. (~1m2/day/system)

How many events?Scanning Power

1 m2/day/system~ 100events/day/system

( OPERA like ECC 1event/brick ~100cm2/event)

~25,000events/year/system

Normally one lab has ~10 system

~250,000 events/year/lab.

Events in Neutrino Factory

160,000 events/kton

(L=3000km,1021mu+ decays)

Event selection for 10kton

• 10kton Total event: 1,600,000

= 1,600,000/250,000

~ 6 Lab ・ year

　　 Loose-selection is Acceptable.

• During the RUN : Extract and Analyze wrong sign muon events.

End of the RUN : Extract all bricks which have tagged neutrino interactions in it.

L3 Magnet　0.5T

OPERA 1SM 850t Or Modified ATLAS TROID

Related Works

• OPERA Exposure will start at the middle of 2006. Scanning in many Labs (Japan, Italy, France, Swiss….)• PEANUT Test exp. at NUMI near detector site. Start neutrino exposure at Aug. 2005. Plan: Test of “ ECC in Magnet” with Permanent magnet (2006).

OPERA 1st Super Module

2nd Super Module

PEANUT Detector :DONUT SFT+ Mini Brick Wall

MINOS Near detector as mu ID

Location of Neutrino interactions in ECC brick

1. Pick up tracks in the most downstream plate

Neutrino

2. Follow tracks to the interaction veretex

P measurement using Multiple Scattering

rms

rms 1

n n : number of measurements

For example: 10 GeV/c has rms deflection of 0.3m

Kinematical AnalysisMomentum

measurement

Momentum measurement

Low dE/dX

Higher dE/dX

Consistent with Pion

Consistent with Proton

P measurement using Multiple Scattering

Expected Value for pion

Expected Value for proton

Resolution p