350 likes | 520 Vues
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. Intrinsic position resolution.
E N D
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
Intrinsic position resolution M.I.P. Track Fog Compton Electron 100mm Cross sectional view of an emulsion layer Ag grain after development M.I.P. Track dx s= 0.06mm 30grains/100mm grain diameter ~ 0.6mm One Emulsion Layer = vector chamber with 60nmposition resolution & ~1mrad Angular resolution (100micron layer)
100mm 125mm 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
Refresh Cosmic-rays Before Refresh After Refresh Compton electrons by γ rays of natural radio activity We can reset the accumulated images by Refreshing. Before use or re-use Emulsion film accumulates all signals during its live time :No dead time.
10cm 12.5cm 8cm OPERA ECC Brick 8kg: Portable Unit for 2~10kton detectors
Decay search 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 τ film Fe
dE/dX measurement P=1.2GeV/c Hadron+ @KEK/PS Film Pb dE/dX = b measurement p P dE/dX ~number of grains
dE/dX measurement : TEST exp at KEK 0.4 GeV/c 0.5 GeV/c 0.6 GeV/c Entry 996 tracks Entry 1310 tracks Entry 1278 tracks • Using only 5 ~ 6 films. • VPH, measured by the system, is ~propotional to dE/dX. π π π P P P D VPH 0.74 GeV/c 0.87 GeV/c 1.14 GeV/c 2.0 GeV/c Entry 1610 tracks Entry 1345 tracks Entry 1175 tracks Entry 1206 tracks π π π P P&π P P D D D D
Particle ID by dE/dx Measurement KEK Beam Test Preliminary dE/dx (MeV・cm2/g) P K π e VPH P andπ Momentum(GeV/c) 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.
Electron ID 50GeV electrons + muons Test Exp. @ CERN
Test exp. @ CERN Electron energy measurement MC Data Energy determination by calorimetric method ( in study) @ a few GeV
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 DONUT/OPERA type target + Emulsion spectrometer mu B Air Gap Stainless steel or Lead Film ~ 3Xo ~10Xo Assumption: accuracy of film by film alignment =10 micron (conservative). (Ex. 20mm gap structure gives 0.5mrad angular resolution.)
Charge determination (0.5T)MC >=30mm Gap 20mm Gap 10mm Gap
Momentum resolution(0.5T)MC 10mm Gap 20mm Gap 30mm Gap 40mm Gap 50mm Gap
Charge determination (1.0T)MC >=20mm Gap 10mm Gap
Momentum resolution(1.0T)MC 10mm Gap 20mm Gap 30mm Gap 40mm Gap 50mm 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 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: |q|<0.4). OPERA Automatic Scanning
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 • Ultra High Speed Imager • 120 fps -> 3000 fps • Image taking by follow shot • X-Y stage : Non-stop • Objective lens: Driven by piezo electric devices (fres>2kHz ). • Enlarging size of Field of View • Effective FOV: 100mm×100mm-> 140mm×140mm Ultra High Speed Imager with Real Time processing Synchronized motion to cancel relative velo. Stage moves at constant velocity 1cm2/h -> 60cm2/h
Scanning System History views/sec 2 m 1view=120×90 m ) ( 60 100 10 3 1 0.25 0.1 0.008 0.01 0.001 TS(TTL) NTS(CPLD) UTS(FPGA) S-UTS Evolution of the Scanning Power CHORUS DONUT OPERA Our code name (device technology)
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.
Or Modified ATLAS TROID OPERA 1SM 850t L3 Magnet0.5T
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).
2nd Super Module OPERA 1st Super Module
MINOS Near detector as mu ID PEANUT Detector :DONUT SFT+ Mini Brick Wall
Location of Neutrino interactions in ECC brick 1. Pick up tracks in the most downstream plate Neutrino 2. Follow tracks to the interaction veretex
Kinematical Analysis Momentum measurement Pb measurement using Multiple Scattering For example: 10 GeV/c has rms deflection of 0.3mm
Momentum measurement Pb measurement using Multiple Scattering Expected Value for pion Low dE/dX Consistent with Pion Resolution s pb ~16% Expected Value for proton Consistent with Proton Higher dE/dX