Event Location Rehearsal in PEANUT Bricks OPERA collaboration meeting Gran Sasso, May 2006 Kodama, Sato, Fukuda, Komatsu, Narita, Nonoyama NAGOYA

We started event location rehearsal in March 2006 using PEANUT bricks. First report has been presented at Project Board on 24 th March 2006 at GS. –4 rock muon events and 1 neutrino interaction candidate –It took about 30min/event for scan back Current status of this rehearsal is presented here.

Key feature PEANUT brick Real OPERA brick –Film : Real OPERA film Tono refreshed (BL118: D01) same process batch films are shipped to GS in boxes NAGOYA+05098,05104,05106… –Lead plate: OPERA lead plate (PbSb) X-ray mark –Plate to plate alignment CS emulation by Scintillation fiber tracker –Most downstream doublet film + SFT = CS We can tag single track for location test

PEANUT BL118 –Brick assemble : Nov./25/2005 –Beam exposure : Nov./25/2005-Feb./28/2006 –X-ray marking : Mar./15/2006 –De-packing : –Arrival from Fermilab : Mar./20/2006 –Develop : Mar./20/2006 –Doublet film scan : Mar./21 (20hour by S-UTS) –CS emulation by SFT matching : Mar./22 –Track follow trial : Mar./22 –Location trial : Mar./23

X-ray Generator X-ray mark exposure bench OPERA Proto-type 1m Exposure time : 5 sec Angle : 4.8 degree Slit: Kim, System: Zama

X-ray Fermilab We brought X-ray exposure bench to Fermilab X-ray generator X-ray slit 50  m wide PEANUT brick X-ray slit

Scanning using X-ray X-ray Brick Intersection of two planes (X-ray) defines a reference line in the Brick. Reference Point X-ray

CS emulation (SFT matching) S-UTS scanning –tan(  )<0.15, 100cm 2 x 2 film = 20hour –1187 matched tracks tagged in 2mm, 40mrad mm rad

CS Emulation Data Taking General Scan on plates 01 and 02 to pickup tracks matching to SFT. Scanning Status –UTS scan is to recover limited angular acceptance of current S-UTS BrickS-UTS scan  <0.15rad UTS scan  <0.40rad BL118DoneReady soon BF021DoneNot yet BL112DoneNot yet All PEANUT bricks in Nagoya with X-ray mark printed.

Rock Muons Scanned –BL11842 tracks –BF02114 tracks Mean UTS efficiency –0.70 with x40 dry objective lens –PH  8 Scanning Time –20 ~ 40 min/track Rock Muon Scan Back All of them penetrated Angle difference between pl.03 and SFT rms ~ 7mrad

To calculate a predicted position, relative position between emulsion plates were obtained by Xray marks ONLY Alignment by Xray for ScanBack Accurate enough 1view of x40 dry objective Found position - Predicted Neutrino beam

Scanning Time for Rock Muons Rehearsal begins on 22-Mar 01-Apr 01-May Events/day We have to run at 30events/day # of plates scanned scanning time (min)

Event Selection for Rehearsal Multi track vertex Veto Kink

Multi Track Vertex

Veto

Kink

Scan Back Result EventSelection category SFT matching at pl01-02SFT Matching at pl03 Scan Back Result Note dxdydtxdtydtxdty BL Multi Penetrated BL Multi Stop at pl45Neutrino Int. Cand. BL Multi Penetrated BL Multi Penetrated BL Multi Stop at pl37Neutrino Int. Cand. BF Multi Penetrated BF Kink PenetratedKink BF Kink PenetratedKink BF Multi Penetrated BF Multi Penetrated Measured at pl02

Event BL

Located Neutrino Interaction in BL118 Event 1105 Scan Back Track Tx = Ty = Tx = Ty = Neutrino beam These tracks have IP=1.7micron at 199micron upstream from up surface of plate 37 No track in up stream plate pl.37 pl.38

Event BL

Scan Back Track T0 ( , ) → stopped at pl.45 Vertex confirmation: Try to find partner track manually, which was seen in SFT, assuming a vertex in an lead plate upstream of pl candidate tracks ( T1 and T2 ) were found. –Both are almost parallel and about 5micron apart. –T1 angle = ( , ), min. distance to T0=6micron at dz=231micron –T2 angle = ( , ), min. distance to T0=2micron at dz=289micron Both T1 and T2 were not found in upstream plate ( pl.46 ). In downstream plate ( pl.44 ), T2 was found, but T1 was not found. Follow down T2 was followed down to pl.02 T2 angle at pl.02 is ( , ) and SFT is ( , ) Good match. T1 might be low momentum pion and T2 is probably a proton. dE/dx……. Event BL

pl01 Stopped at pl45 neutrino Scan Backed Track T0 Partner Track T2

Event BF

pl01 pl57neutrino (Tx,Ty) = ( , ) in emulsion ( pl02 ), ( , ) in SFT (Tx,Ty) = ( , ) in emulsion ( pl57 ), ( , ) in SFT NOTE : 1 ion plate exists upstream of pl57

pβ= 733±97 MeV/c Event BL Momentum estimation Tscat 2 = ( DT of THE track ) 2 – ( DT of a rock muon ) 2 DT of THE track Every 2 plates DT of a rock muon Every 2 plates 意味が無いかもしれませんが、 Rock muon の運動量が十分高いと仮定しての運動量推定です。

Event BF

pl01 pl57 neutrino (Tx,Ty) = ( , ) in emulsion ( pl02 ), ( , ) in SFT (Tx,Ty) = ( , ) in emulsion ( pl57 ), ( , ) in SFT NOTE : 1 ion plate exists upstream of pl57

Scan Back Result ( continued ) EventSelection category SFT matching at pl01-02SFT Matching at pl03 Scan Back Result Note dxdydtxdtydtxdty BL BL Multi Penetrated same event BL Multi Penetrated BL Multi Stop at pl43Neutrino Int. Cand. BL Multi Penetrated

Event BL

Scan Back Track (T0) Tx = (SFT) Ty = (SFT) Partner Track (T2) Tx = Ty = Neutrino beam These 4 tracks have IP=0.8 micron at 138 micron upstream from up surface of plate 43 pl.43 Event BL  Partner Track (T1) Tx = Ty = (SFT) Partner Track (T3) Tx = (SFT) Ty = (SFT)

Summary PEANUT Analysis ： Realistic exercise for OPERA event Location, Scan back, Vertex confirmation and Follow down with real neutrino events. Really OPERA rehearsal. System R&D, Human exercise etc are going on……………….. X-ray mark alignment works perfectly Currently, it took 30 minutes for track follow from bottom to top. –In this time, manual checks were applied to all of the scanned point. –We are sure, we can achieve 10 minutes for track follow. We are CONFIDENT to carry out location for 30event per day with only one system. –Vertex analysis after location will be done by other UTS system. Up to now, 4 bricks ( Cosmic, BL118, BF021, BL112 ) have been made to TAPE and 3 of them have been scanned. Systematic Vertex confirmation study will be started for stopped events.