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)