slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
The OPERA hybrid detector was designed to search for n t appearance in the n m CNGS beam PowerPoint Presentation
Download Presentation
The OPERA hybrid detector was designed to search for n t appearance in the n m CNGS beam

Loading in 2 Seconds...

play fullscreen
1 / 31

The OPERA hybrid detector was designed to search for n t appearance in the n m CNGS beam - PowerPoint PPT Presentation


  • 75 Views
  • Uploaded on

LNGS. CERN. L = 732 km. The OPERA hybrid detector was designed to search for n t appearance in the n m CNGS beam. T flight = 2.44 ms. CNGS. Expected neutrino interactions for 22.5x10 19 pot: ~ 23600   CC + NC ~ 205  e +  e CC ~ 115   CC (m 2 = 2.5 x 10 -3 eV 2 ).

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The OPERA hybrid detector was designed to search for n t appearance in the n m CNGS beam' - ciaran-landry


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2

LNGS

CERN

L = 732 km

The OPERA hybrid detector was designed to search for ntappearance in the nm CNGS beam

Tflight = 2.44 ms

CNGS

Expected neutrino interactions for 22.5x1019 pot:

~ 23600  CC + NC

~ 205 e +e CC

~ 115  CC (m2 = 2.5 x 10-3 eV2)

OPERA

slide3

Detection principle for nt appearance in OPERA

ECC brick

1 mm

electronictrackers



Pb

emulsion layers

interface films (CS)

Detection of ntCC events through characteristic topology

slide4

Dipolar magnet spectrometerwith RPC and drift tubes

Brick manipulator system

2 SuperModules

SM1

SM2

Pb-Emulsion Target +Target Tracker

VETO

slide5

neutrino

OPERA: sub-micrometric tracking precision of nuclear emulsion+ time trigger, kinematics and particle ID by electronic detectors

Hybrid target structure

10.2 cm

(CS)

7.5 cm

10 X0

12.5 cm

(CS)

1 brick = 56 Pb plates / 57 emulsion films

150,000 ECC bricks (ECC=Emulsion Cloud Chamber) 111,000 m2 surface, 8.9 million films

1.25 kton of “instrumented” target

slide6

Microscopic Image

emulsion(44mm)

50 micron

plastic base(205 mm)

emulsion(44 mm)

sensitivity : 32grains/100 mm

Emulsion films: optical “tomography” of the vertex region

Track fitting residuals 50 nm

A m.i.p. track in emulsion

nm beam

3D tomography:change focal plane

slide7

Reading the emulsion films – “off-site” detectors

High speed automatic microscopes:

~ 200 cm2 emulsion film surface/hour/facility

Based on state of the art technologies:

precision mechanics, high-speed CMOS, pattern recognition, image analysis

Data flow:  1 GB/s/facility

European Scanning System

Super-UltraTrackSelector

slide9

Target Tracker planes interleaved with brick walls

> 5 p.e. for a m.i.p. (2.15 MeV)

~ 99% detection efficiency

position accuracy: 10 mm

angular accuracy: 23 mrad

TT: 6% of target mass

Walls: 0.5% of target mass

slide10

Target Tracker

p.e. for a m.i.p. track as a function of the distance from each end

Empty dots: MC

Full dots: data

slide11

The magnetic spectrometers:

  • 1.52 T magnetic field bending particles in the horizontal plane
  • 24 slabs of magnetized iron interleaved with 22 RPC planes
  • 6 drift tube stations (HPT) for precision measurement of the angular deflection
  • Momentum resolution:
  • 20% below 50 GeV
slide12

The magnetic spectrometers

Momentum  charge, data (dots) vs. MC (lines)

Charge misidentification: 1.2% (2.5 GeV < p < 45 GeV)

slide13

RPC’s for tracking in the magnet and range measurement

RPC efficiency

3500 m2bakelite RPC’s operated in streamer mode:

Hadronic energy reconstruction in the spectrometer

Trigger for the HPT

Coarse tracking of showers (2.6 cm strip pitch)

slide14

How neutrino interaction events look like in the OPERA electronic detectors

1m: event with a min the final state

20 m

0m: event without a m in the final state

slide15

Neutrino interaction energy reconstruction

1m events

0m events

Reconstructed energy:

Dots = data

Lines = MC

The instrumented target is used as a calorimeter

Energy resolution

slide16

How a t-neutrino candidate looks like in OPERA

Vertex region

Vertex region (zoomed view)

Electronicdetectors

slide17

Topological signature through the observation of the in-flight decay of a tau lepton: ct87 mm requires micrometric tracking

slide18

Info from emulsion films: topological reconstruction

Interaction/decay vertex:the minimum distance point of two or more tracks

The Impact Parameter has an average value of 2.3 mm (real events)

  • IP distribution for:
  • - nt events (MC)
  • NC+ nmCC events (MC)
  • NC+ nmCC events (Data)
slide19

Info from emulsion films: momentum estimation through measurement of multiple Coulomb scattering

Dp/p

s = (22±4)%

slide20

Info from emulsion films: EM shower reconstruction + energy estimation

2 EM showers give a reconstructed mass ~ 160 MeV/c2

  • Shower energyis estimated bya neural-networkanalysis of the shower feaures:
  • # of tracks
  • shape
  • MCS of hard tracks

p0 mass measuredin emulsion

35 events

E = 8.1 GeV

E = 0.5 GeV

slide21

Info from emulsion films: discrimination of interaction/decay kinks by search for highly ionising particle tracks

Fine emulsion sampling (0.5 mm tomography) to check track length and discriminate radioactivity from nuclear fragments

slide22

Merging electronic detector information with emulsion information, #1:

the Changeable Sheet (CS) doublets

Extract brick and CS, scan CS.

Confirm the event in the brick.

Develop brick: ship to scanning labs.

CS

σx ∼ 10.0 mm

slide23

On-demand brick handling

Waiting for neutrinos in the target…

X-ray exposure for alignment

Extracted by the Brick Manipulator System

Stored underground (waiting for the CS response)

Films developed in surface emulsion facility

Exposed to cosmic-rays for precision film alignment

slide24

Emulsion film scanning: several labs share data-taking

To Dubna

Bern

Analysis

BMSDB

Padova

IN2P3

OPFRA

Bologna

DevDB

Nagoya

OPITA

Bern

BAMDB

To Japan

LNGS

Roma

To Ankara

Bologna

LNGS

LNF

LNF

Bari

Dubna

Napoli

An interconnected system of relational DB’s distributes all intermediate results and holds the analysis status of each event

Currently 15 TB, expected to top 100 TB

Salerno

Padova

LNGS

Roma

Bari

Salerno

Napoli

slide25

Merging electronic detector information with emulsion information, #2:

locating the neutrino interaction

CSd

 ~2 µm

nm

2

1

1

53

57

48

49

50

51

52

54

55

56

2

Volume scanning (2cm3) around the disappearance point

slide26

Merging electronic detector information with emulsion information, #3: event study

  • Estimate the total visible energy
  • Match event shape to vertex region and check track origin
  • Assess the nature of eachparticle for interesting events
  • Each track is followedthrough the Target Tracker, CS doublet andtarget brick sheetsuntil the endpoint isreached and checked

C

slide27

Merging electronic detector information with emulsion information, #3: event study

The combined emulsion + electronic information is reported for the nt candidate eventAll cuts from OPERA Proposal passed

The most likely interpretation in this case is:

The OPERA hybrid apparatus allows detailed study for each single event!

slide28

Sample event: charm candidate

x-view

1ry muon

1ry

vertex

kink

daughter muon

1.3 mm

slide29

Sample event: charm candidate

AB=361 mm

Pl21

Pl20

nm

Pl20

A

B

5

Pl20

Pl20

Pl20

Pl21

2

m

C

C: hadroninteractionvertexAC =1640 mm

Pl22

Pl21

slide30

The whole machinery running

3432 eventslocated (2008+2009 runs)3162 eventsdecaysearched (‘08/’09)

Pl20

slide31

Conclusions

  • The OPERA Collaboration is successfully operating a hybrid detector to search for nt appearance in the CNGS beam
  • The hybrid design concept in OPERA allows detailed study of each event, exploiting the best features of its nuclear emulsions, scintillators, RPC’s and drift tubes
  • 1 nt candidate was found in 2010 out of a sample of 1088 fully analysed events
  • 3162 events searched for decays so far (41 with charm production/decay in nm interactions) from 2008/2009 runs
  • Data taking in progress, more results to come in the near future!