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Segmented Segmented
magnetised magnetised
detectorsdetectors
Anselmo Cervera VillanuevaAnselmo Cervera VillanuevaUniversidad de ValenciaUniversidad de Valencia
ISS meetingISS meeting RAL (UK) 25/04/06RAL (UK) 25/04/06
22 Overview Overview
General aspectsGeneral aspects
Signal and backgroundsSignal and backgrounds
Detector conceptsDetector concepts
ConclusionsConclusions
33 General aspectsGeneral aspects
In the DIS regime water cherenkov is not suitable
One needs a detector capable to measure the hadronic energy
In a neutrino factory the measurement of the muon charge is mandatory
Segmented magnetised detectors are one of the proposed solutions
44 BackgroundsBackgrounds
The golden signal: wrong sign muons
The backgrounds are:Muon misidentification (mainly pions)
Wrong sign muons from , k decays
Wrong sign muons from D decaysHadronic angular resolution helps
There is a irreducible component
Charge misidentification of right sign muonsThe ratio (multiple scatt.) /(distance between active planes) is crucial
All of them increase when going to low muon momentum
55 Detector requirementsDetector requirements
Large mass: 40-100 KTons
Magnetic field: ~1 T
Transverse resolution: ~1cm:Important for D decay rejection
Longitudinal segmentation:Important for the charge
Large radiation lengthImportant for the charge
66 Active partActive part
Scientillators:Type
Solid (MINERVA, MINOS, LMD)
Liquid (NOvA)
RedoutPMTs (MINOS)
APDs (Minerva, NOVA)
RPCs (Monolith, INO)
77 LMDLMD
iron (4 cm) scintillators (1cm)
beam
20 m
10 m
10 m
B=1 T
1cm transverse resolution
• Studies have been done for very small . • Aim for very small background levels (10-5) • Strong cut on muon momentum (>5 GeV) • Problems to measure the charge of muons below 3 GeV• Interesting for intermediate distances (3000 km) to measure very small Essentialy free of
backgrounds• But not for second oscillation maximum ( 2-3 GeV)
• For large the performance should be good. We must check it !!! By lowering the muon cut.
88 The INO conceptThe INO concept
ISS-CERN 22-24 September, 2005
Naba K Mondal Tata Institute of Fundamental Research
Mumbai, India
Similar to LMD but suitable for larger distances because the charge measurement is less efficient (longer distance between measurement planes)
Interesting for large distances (~7000km, CERN/RAL-INDIA)
Good for the mass hierarchy
Is there a design optimised for Nufact (vertical planes) ?
99 The TASD (The TASD (A)A)ConceptConceptSuitable detector for:
High gamma beta beam (non magnetised)
Neutrino factory: baselines < 3000 Km
because it has good detection efficiency down to low neutrino energies (1-2 GeV). Could detect first and second oscillation maxima at intermediate distances:1000-3000 Km
See talk by M. Ellis
1133
Probably the optimum detector is in between NOvA and LMD: liquid scintillator with some iron to facilitate the magnetisation and increase the mass.Detector regions optimised for the measurement of the muon charge is another possibility
1155 Iron free regions ?Iron free regions ?
A muon of 1 GeV will traverse at least 1 iron-free module One has to design the detector such that the muon traverses at least one iron-free module after the extinction of the hadronic shower, to facilitate pattern recognition. The measurement of the momentum and the charge is considerably improved in the iron-free region. One can probably reduce the number of active planes in the iron region:
Less hadronic energy/angle resolution. Find a compromise.
1mIron (4cm) + active (1cm) Iron (4cm) + active (1cm) air + active (1cm)air + active (1cm)
hadron showerhadron showermuonmuon
This full structure is repeated
Paul SolerA. CerveraISS-CERN
1166 Combining NOvA + iron freeCombining NOvA + iron free
Studies going on by the Valencia/Geneva group. Results this summer
? Iron (2cm) + active (4cm) Iron (2cm) + active (4cm) air + active (1cm)air + active (1cm)
hadron showerhadron showermuonmuon
Liquid scintillator iron
1177 ConclusionsConclusions
Segmented magnetised detectors are the best option to study the golden channel
Small
Iron detectors can measure it very well. But problems with CP
A TASD detector would do it better
Large
In principle, no problems with iron, even for CP. To check !!!
TASD is still good
Problems with TASD:Magnetisation
Low density: need larger detector
Studies going on by several groups (talk by M. Ellis)