Neutrino detectors
for future neutrino beams
Stefano Ragazzi
NuFact05
NuFact04
• Paolo Strolin gave an excellent and comprehensive talk
Stefano Ragazzi
NuFact05
Main progress since NuFact04
Stefano Ragazzi
NuFact05
Paolo at NuFact04
Stefano Ragazzi
NuFact05
I can’t compete with Paolo’s review
• Just one subject left to me…
Where do we stand with (conceptual)
beam-detector optimization for b-beams
and neutrino-factory beams?
Stefano Ragazzi
NuFact05
Neutrino beams of the (far) future
• Beta beams and neutrino factory beams will
have no intrinsic background (unwanted
neutrino flavour) and precisely known
spectrum and intensity
• Are we ready with detectors, at least at the
conceptual level, to fully exploit their
exceptional quality?
Stefano Ragazzi
NuFact05
Beta beams
• Beta beams will be pure ne or anti-ne beams with
spectrum controlled by b-decay at rest of the
parent nuclide (e.g. 18Ne or 6He) and g (~100) of
the parent: typical neutrino energy few 100 MeV
• Look for nm appearance at few 100 MeV
n m  ( A, Z )  m   hadrons
• background
n e  ( A, Z )    hadrons

Stefano Ragazzi
NuFact05
Beta beams - 2
•
Background reduction:
1. Require identified m+ decay: - and interacting + are
elimianted, but stopping + survive
2. Fine tune beam energy: suppress  production not
suppressing too much m production
3. Final background ~ 4·10-4
Stefano Ragazzi
NuFact05
Beta beams - summary
• Background reduction is mainly obtained by
beam tuning
• Any detector sensitive to muon decay is fine
“brute force” detector R&D
• Maximize detector mass
• Minimize detector cost
Unless you can conceive a massive detector
with /m separation
Stefano Ragazzi
NuFact05
Beta beams: a different approach
P.Migliozzi, F. Terranova, A. Marotta, M. Spinetti hep-ph/0405081
1. Increase as much as possible beam energy
2. Filter out pions
Stefano Ragazzi
NuFact05
Neutrino Factory
•
20-50 GeV pure nm+ne beam (or CP conjugates)
•
Search for appearance of ne or nm: wrong sign electron or
muon: magnetic field is essential to identify lepton
charge
1.
wrong sign electron
2.
Liq. Ar + magnetic field
 see André Rubbia talk on Saturday (WG1?)
wrong sign muon
magnetized iron detector
Stefano Ragazzi
NuFact05
Magnetized iron detector - 1
1. a very conceptual design: LMD
Stefano Ragazzi
NuFact05
Magnetized iron detector - 2
2. a beautiful MIND (a.k.a. Monolith, INO, …)
Fe
Fe
Stefano Ragazzi
NuFact05
2.2 cm
8 cm
Magnetized iron detector - comments
• detector 1 looks somewhat too much
conceptual
• a technical design exists for detector 2,
however det. 2 was cost optimized for a
zero cost neutrino beam (atmospheric)
• Neutrino Factory may deserve something
better…
Stefano Ragazzi
NuFact05
(
Stefano Ragazzi
NuFact05
Stefano Ragazzi
NuFact05
)
Stefano Ragazzi
NuFact05
Magnetized iron detector background
1. Wrong charge assignment to leading muon
•
reduce with momentum cut and track fit cut
2. Wrong charge assignement due to -decay or m
from heavy quark decay
•
reduce with isolation cut (e.g. require minimum
transverse momentum of the leading muon with
respect to hadron jet)
Stefano Ragazzi
NuFact05
A few questions…
1. Can we rely on bkg estimates at 10-5-10-6 level?
2. Can we / should we improve detector
performance?
3. How? R&D on what? Detector structure? Bfield? Tracking? Ehad measurement?
4. How does MIND perform?
Stefano Ragazzi
NuFact05
and answers…
• In 2001 Marco Selvi made a systematic
comparison of MIND (he liked to call it Monolith)
to LMD performance
• Although he did not try to parametrize the effects
of B-field, tracking, sampling, hadronic energy
flow reconstruction, in his analysis we find several
hints to the relevance of these detector
characteristics
• Hints to detector optimization
Stefano Ragazzi
NuFact05
Charge identification
Generate interaction using Pythia + q.e. + 1
corrections (Lipari code).
o Simulate the whole event in Geant:
o Multiple scattering with Moliere theory option ON
(not just gaussian approximation)
o Full B field description
o Fit muon track using GEANE and Kalman filter
approach
(a real reconstruction, not just smearing)
o
both for signal and background
Stefano Ragazzi
NuFact05
Neutrino Oscillation Working Group at CERN – 11 dec 2001
M. Selvi - INFN Bologna
B field details
n
n
Stefano Ragazzi
NuFact05
Charge identification: results
Selection cuts:
•
Pm from range > 7.5 GeV
•In each region:
• At least 4 points
•Track lenght > 300
•Same
cm
charge assigned in each region
Fractional bkg.
1 x 10-6
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
Efficiency
35%
M. Selvi - INFN Bologna
Wsm from hadrons
Large Magnetic Detector people showed (see Sitges
Workshop Cervera’s talk)
that it is possible to reject such bkg up to
~ 2 x 10-6
with 24% efficiency
just using two cuts:
•
Pm > 5. GeV
•
Qt > 1.4 GeV
Qt = Pm sin2
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
M. Selvi - INFN Bologna
... What can Monolith say?
•
•
Pm cut may be easily reproduced:
• good muon momentum resolution
Qt depends on hadronic angular resolution
• in LMD analysis they assume to have the same
performances of MINOS (MINOS proposal chapter 7)
• in MONOLITH: it has to be checked !!
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
M. Selvi - INFN Bologna
hadronic angular resolution
Reconstructing vertex:
about twice MINOS
Monolith fit
32.
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
8.2
M. Selvi - INFN Bologna
First approach
• Just use a hard momentum cut (Pm >20 GeV)
and forget about the angular resolution.
Fractional bkg and efficiency
Charge
misid.
nm
1. 10-6
MONOLITH
3. 10-6 1. 10-8 1. 10-6
35
100
.6
1. 10-6
1.1 10-6
LMD
1. 10-7 2. 10-7
35
38
6
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
CC
ne
CC
nm ne

NC
11 %
30
24 %
5.6
M. Selvi - INFN Bologna
Improvements
• Higher granularity
• Planes orientation
... perform the same cuts
(Pm >5. GeV; Qt > 1.4 GeV) and modify the
fractional bkg accordingly with the
obtained hadronic direction smearing
Efficiencies are considered to be the same
(16.5%)
Very conservative hypothesis:
improvements are expected in both cases
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
M. Selvi - INFN Bologna
Vertical plates – 8 cm thick
Monolith fit
15.
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
12.
M. Selvi - INFN Bologna
Marco compares MC whth test beam data…
hadronic angular resolution
MC and Data
comparison:
5cm thick
plates
3cm strip width
Stefano Ragazzi
NuFact05
Neutrino Oscillation Working Group at CERN – 11 dec 2001
M. Selvi - INFN Bologna
hadronic angular resolution
MC and Data
comparison:
10cm thick
plates
3cm strip width
... Also 10cm agrees
with MINOS fit
(reference one) !!!
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
M. Selvi - INFN Bologna
and a final remark
Comment about LMD
How will this muon
track be
measured?
What has been
simulated:
Neutrino Oscillation Working Group at CERN – 11 dec 2001
Stefano Ragazzi
NuFact05
M. Selvi - INFN Bologna
Roadmaps for mag. Det. R&D -1
• Start with baseline or well known design (MINOS)
– Parametrize effects on bkg reduction of
•
•
•
•
Magnetic field
Tracking
(Average hadron interaction length)
Ehad resolution and energy flow reconstruction
– Redesign your baseline detector
– Step into roadmap 2
Stefano Ragazzi
NuFact05
Roadmaps for mag. Det. R&D -2
• Start with the assumption that Marco did most of the
job
– Ask a mechanical engineer about max. dimensions of
plates that can be hang vertically
– Magnetic field design
– Baseline detector design
– Start R&D for stable, reliable, easy to install active
elements
Share R&D with linear collider had-calorimeter?
Stefano Ragazzi
NuFact05