Neutrino Event location Connection from Electric Detector to Emulsion Detector Tsutomu FUKUDA Fundamental Particle Physics Lab, Nagoya-univ 9th March, Workshop “New Developments of Flavor Physics”

The OPERA Detector ν ECC 10cm 2.6cm 12.5cm Changeable Sheet (CS) T TT T

Emulsion layers 44micron Base 205micron 12.5cm OPERA film x 2 10cm Neutrino beam The Changeable Sheet (CS) 600micron 160micron OPERA film X Z

The Changeable Sheet (CS) 128mm 79mm ECC CS neutrino 103mm Packing and Box install

26mm 100mm ECC CS TT

26mm 100mm ECC CS TT

26mm 100mm ECC CS TT

Role : Brick tagging DONUT OPERA 10cm ECC SFT [Electric Detector]Scintillation Fiber tracker (DONUT, CHORUS) Target tracker (OPERA) Segmentation 0.5mm26.4 mm Tracking○ × (only μ→ ○) 10cm ECCTT

The Roles of CS Brick tagging  Saving Scanning load and Target Mass Pick up tracks from neutrino interaction We can locate Neutrino interaction easily, because we have experience of Event location in DONUT exp, PEANUT(OPERA rehearsal) exp … If we get good Track on CS…

Required Scanning Power 5mm x 5mm 5cm x 5cm OPERA 1μevent 10cm x 12cm OPERA 0μevent DONUT ~ CHORUS 1mm x 1mm 1996

Requirement for CS analysis Very large scale Scanning Power Picking up tracks from neutrino interac- tion from Scanning Data without fail

S-UTS Speed = 50cm 2 /hour 50 times of old type machine

Running 4 SUTS (’08 Run) 9.8 CS/day → 68.6 CS/week 5 SUTS (’09 Run~) 12.6 CS/day → 88.2 CS/week SUTS Scanning Shift SUTS Running Speed SUTS machine time ~90% : CS scanning ~10% : ECC scanning (used 1SUTS)

Status of CS Scanning at 2008 ’ Run 697 CS Scanned (~ 12:00, March 5 th, 2009) Middle of July ‘08 (day)

10cm 12.5cm SUTS Scanning DATA 角度精度 ： 15 mrad 位置精度 ： 0.9 micron Recognized Tracks in one emulsion layer Total ~ 140M tracks We must search a few real tracks from neutrino interaction ! 140M tracks  a few tracks

Track selection 1 4 layer coincidence

Track selection 1 4 layer coincidence ~140M  ~3000

Track selection 2 X-ray Alignment X-ray mark Sigma ~ 5.5 micron Sigma ~ 7.6 micron Expose X-ray penetrating CS. Spot size ~ diameter 100micron.

Track selection 2 Compton Alignment Sigma ~ 2.0 micron We developed new alignment method. By using compton electron penetrating 2 emulsion layers, we achieved high accuracy alignment. ~3000  ~300

Track selection 3 Track Ranking Likelihood ( signal, noise ) Signal ~ 90% Noise  1/50 ~300  ~ 6

Track selection 4 Manual check Check by eye and judge true track or fake track (compton-electron). ~6  0 Finally, we make prediction for ECC analysis.

Current status - manual check - Brick finding efficiency ~ 87.9% (421found / 479measured) 479 measured Good track found on CS

Status of CS analysis in OPERA 421 found /697 Scanned (JAPAN) 501 found /796 Scanned (EU) Raise Brick finding efficiency Raise speed of analysis To do:

Summary CS is very important for Event location. CS Scanning is going well. Performance of Track selection is well. Brick finding efficiency and analysis speed should be raised furthermore.

The end