Transcript Diapositiva 1

BENE
Introduction to ISS detector WG
Pasquale Migliozzi
INFN – Napoli
Mandate of the WG
(A.Blondel at the ISS-KEK meeting)
Evaluate the options for the neutrino detection systems
with a view to defining a baseline set of detection
systems to be taken forward in a subsequent
conceptual-design phase.
Provide a research-and-development program required
to deliver the baseline design 
Funding request for three years of detector R&D
2007-2010
Some difficult choices will have to be made in order to most efficiently
utilize the R&D resources that “might” become available
Working groups
Water Cerenkov Detectors
Kenji Kaneyuki, Jean-Eric Campagne
Magnetic Sampling Detectors
Jeff Nelson, Anselmo Cervera
http://dpnc.unige.ch/users/blondel/detectors/magneticdetector/SMD-web.htm
Liquid Argon TPC
Scott Menary, Andreas Badertscher, Claudio Montanari,
Guiseppe Battistoni (FLARE/GLACIER/ICARUS’)
Emulsion Detectors
Pasquale Migliozzi
Near Detectors
Paul Soler
http://people.na.infn.it/~pmiglioz/ISS-ECC-G/ISSMainPage.html
Water Cerenkov
The MEMPHYS Project
65m
CERN
130km
65m
Water Cerenkov modules at Fréjus
Fréjus
4800mwe
CERN to Fréjus
Neutrino Super-beam and Beta-beam
Excavation engineering pre-study has been done for 5 shafts
Main results of the preliminary study
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the best site (rock quality) is found in the middle of the
mountain, at a depth of 4800 mwe
of the two considered shapes : “tunnel” and “shaft”, the
“shaft (= well) shape” is strongly preferred
Cylindrical shafts are feasible up to : a diameter  = 65 m
and a full height h = 80 m (≈ 250 000 m3)  215 000 tons
of water (4 times SK) taking out 4 m from outside for veto
and fiducial cut 146 000 tons fiducial target
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3 modules would give 440 kilotons (like UNO) BASELINE
4 modules would give 580 kilotons (HK)
with “egg shape” or “intermediate shape” the volume of the
shafts could be still increased
The estimated cost is ≈ 80 M€ X Nb of shafts
Photodetectors
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Baseline: photomultipliers
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AIM: get the highest possible coverage to get the lowest possible threshold. Ideally, the same
light/MeV as SuperK
The 20”PM is to expensive (12.6€/PE) compared with the 12”PM (7.7€/PE). The latter has also
the advantage of a better timing and position resolution
Ongoing R&D on HPD together with PHOTONIS
Ongoing R&D for electronics (ASIC’s) and mechanics
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AIM: low cost 200€/channel
A possible schedule for MEMPHYS at Frejus
Year
2005
Safety tunnel
Lab cavity
2010
2015
2020
Excavation
P.S
detector
Det.preparation
Study
PM R&D
Excavation
PMT production
Outside lab.
Installation
P-decay, SN
Non-acc.physics
Superbeam
Construction
Superbeam
betabeam
Construction
Beta beam
decision for cavity digging
decision for SPL construction
decision for EURISOL site
Superbeam + beta beam together
SUPERBEAM
4 n flavours + K
2yrs nm → ne
2 beams
1 detector
BETABEAM
pure
ne → nm 5yrs
p+/p-
8yrs nm → ne
ne → nm 5yrs
2 ways of testing CP, T and CPT : redundancy and
check of systematics
Recently a study on SB + BB + Atmospheric
Neutrinos became available (see next)
The T2HK project
• Tunnel-shaped cavity
• Avoid sharp edges. Spherical
shape is the best
• Twin cavities
• MFD/MTOT worse than single
cavity. But…
• Two detectors are independent.
One detector is alive when the
other is calibrated or maintained
• Staging approach is possible
• The Tochibora mine is considered as a candidate site: very good rock quality
• Photosensors: PMT long-term stability proven, but too expensive. 13” HPD
prototype under test at Tokyo U. Long term stability is an issue
• Photosensors: time production too long. How to reduce it?
Possible experimental set-up
Total cost must
be similar to the
baseline design.
2.5 deg. off axis
2.5 deg. off axis
Distance from
the target (km)
JPARC
2.5deg.off-axis beam @Kamioka
Off-axis angle
NB about 300 Oku-Yen should be included for the beam upgrade
Physics Reach of WC projects
The ATM neutrinos are for free and
should always be used in the
calculations!!!
T2KK is not shown, but it improves the
sensitivity to mass hierarchy
For the MEMPHYS project the results
are good, but could be excellent if both
SPL and BB (plus ATM data) are
exploited: COSTS!
Summary table
Reach
(costs M€)
SPL+ATM
(600+400)
BB+ATM
(600+500)
T2HK+ATM
(600+300)
Θ13
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δCP
*
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Mass
hierarchy
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Octant
|sin2θ23-0.5|>0.07
**
|sin2θ23-0.5|>0.09
*
|sin2θ23-0.5|>0.05
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Detector
Accelerator
These results have been obtained assuming equal systematic errors (2%)
NB The goal of a 2% sys error with a conventional beam is very ambitious.
My comments
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The physics reach of WC detectors is well advanced and based on the
solid bases of previous successful projects. Furthermore, it is very
wide (SPL and/or BB, ATM, Solar, SN, proton decay,…)
Assuming the availability of the needed budget and no correlation with
the T2K/Nova results, 2020 seems to be a realistic date for the start
of data taking. In case of correlation a 5 years delay is possible.
Given that ATM neutrinos are for free and help a lot in solving
degeneracies, it is mandatory to include them in all calculations
An issue is the R&D on photodetectors:
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Costs should be reduced. HPD are promising. For the time being the better PE/MeV
cost is given by 12” PMT
Production rate should be optimized. At present it lasts 10 years the production of
all PMTs for 1Mton detector. Storage space could become a problem
MEMPHYS project: it seems that once the ATM n are included the
SPL performs better than BB (assuming equal sys errors. Optimistic?).
Maybe the BB adopted for the Frejus is not the optimal choice. Of
course SPL+BB gives superior performances but it is very expensive.
Segmented magnetic detector
Basic Detector Concept
7.5 mm
15.0 mm
Considered Extremely Fined Grained
Magnetic field
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Has not been investigated in any detail yet
Considering two options:
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Iron sheets in between scintillator layers.
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Parameters to study are thickness of each sheet and ratio of
scintillator to iron.
More work needed to understand how to accurately simulate
the field and perform reasonable reconstruction.
Air toroid magnet surrounding detector.
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ATLAS magnet is a starting point in terms of scale.
Simulating 0.15 T field to start.
Will study physics parameters (P resolution, charge ID, etc) as
a function of magnetic field
Status @KEK-ISS meeting
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Past month spent in code development and testing.
Simulation now at a stage where they can be used for
production of a high statistics sample for serious analysis.
Reconstruction still requires some work to fine tune track
fit.
Need to define a list in order of priority of conditions to
study and what results are required.
First list looks like:
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Momentum resolution
Charge identification
Particle ID (dE/dx)
Two track separation
Jet angle and total energy resolution
Hadronic response
Neutron detection
Caveat (from A. Bross talk)
Pattern recognition is “perfect” (or cheating!) as I use
Monte Carlo truth to select the hits that belonged to
the primary track (100% purity and efficiency).
Once hits are selected, clustering, space point and
track reconstruction proceed without the use of Monte
Carlo truth information.
Simple digitisation at the moment. Will need to decide
what readout technologies to study in order to chose
more appropriate values.
Is this Detector Scenario Credible?
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Technology is not really an Issue
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COST IS
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Of course the study will also include magnetized Fe
Assume a 25kT all scintillator detector with air-core
magnet (B = 1-3 kG)
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Much larger Fiducial mass
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Or could add non-active target in air-core design
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Cost (solid) - $100M
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$10/ch is possible - $70M
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$0.16/m ~ $16M (Very important optimization – 1 mm fiber is 6X the cost!)
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Not an order of magnitude more than what is acceptable
Scintillator (Solid or Liquid) – No R&D issues
Segmentation as shown here gives » 7 X 106 ch
Fiber Cost – Assume high QE PD and high yield scint. Use
0.4mm fiber
$100M for magnets + infrastructure, etc
Total is something less than $300M
R&D areas
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Photo-detectors
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Already good work progressing on SiPM, MRS, even VLPCs.
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Scintillator
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Technology in place for the most part
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Cost/(pe detected)
Magnets
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Co-extrusion of WLS fiber with scintillator
Adjust plastic density (Z) by adding heavy element
Optimization of Scint+WLS fiber + PD
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Need High QE and reasonable gain
Potential readout chips already exist (integration)
Natural extrapolation from Atlas?
Assembly and integration
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Mild extrapolation from existing detectors
But some significant cost savings with new engineering approaches in a
number of areas
My comments
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The MC digitization should be developed according to the
readout technology
A realistic pattern recognition has to be developed in
order to address the reconstruction issues
The issue of how to magnetize the detector volume has to
be addressed. This could be done together with the
Emulsion WG although they need at least 0.5 T
This detector technology is ONLY suitable for the study
of the “golden channel”
In the case of a “full active” detector, is it possible a
synergy with the MECC technique? (see L.S. Esposito talk)
The cost is not an issue, but a more solid estimate should
be performed
An ideal detector for a NuFact should
Identify and measure the charge of the muon (“golden
channel”) with high accuracy
Identify and measure the charge of the electron with
high accuracy (“time reversal of the golden channel”)
Identify the  decays (“silver channel”)
Measure the complete kinematics of an event in order
to increase the signal/back ratio
A magnetic field is needed!
Two possible technologies:
Liquid Argon TPC
Emulsion Cloud Chamber
industrial study of large Tank
70 m diameter, 20 m drift = 100 kton of Larg
shown to be feasible conceptually
The LAr
TPC
Thanks to A. Rubbia
My comments
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Intensive R&D program going on
The proof of the long drift is a crucial milestone (in progress)
A detailed (magnetic, mechanical, thermal,…) of the coil yet to be
performed
Very important the success of the proposed staged approach: 1 kton
→ 10 kton → 100 kton
Combine the efforts of the European and US communities
Full event reconstruction of neutrino events has to be shown:
important to show the efficiency and background as a function of the
neutrino energy
Define the needed magnetic field in order to efficiently (how much is
driven by physics) measure the electron charge
MECC: the OPERA experience
The detector is being constructed at the Gran Sasso
Laboratory. Meanwhile several tests with charged particles
and neutrinos at FNAL are under way
An ECC brick is a self-consistent object. The whole detector
is just an ensemble of bricks.
“MECC” structure
DONUT/OPERA type target
+ Emulsion spectrometer +
TT + Electron/pi discriminator
B=1T
Stainless steel or Lead
Film
Rohacell
3 cm
Electronic detectors/ECC
Assumption: accuracy of film by film alignment = 10 micron (conservative)
13 lead plates (~2.5 X0) + 4 spacers (2 cm gap) (NB in the future we plan to study
stainless steel as well. May be it will be the baseline solution: lighter target)
The geometry of the MECC is being optimized
Momentum and charge measurements
Questions raised during the ISS@KEK
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Study the MECC performances by
considering a lower magnetic field (< 1 T)
Optimize the target geometry and provide a
reasonable estimate of the maximum
affordable mass
Propose a baseline for the electronic
detector (NB it should not provide accurate
points, it serves only as time stamp)
Provide the energy dependence of the signal
and of the background rates
My comments
(details will be given by L. Esposito)
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The emulsion scanning and the reconstruction programs
are being developed by the OPERA Collaboration
It is possible to achieve the performances shown at the
ISS-KEK meeting by using a 0.5 T magnetic field (the
magnetization is similar to the one under study for the
segmented magnetic detector: synergy)
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How to magnetized a very large volume?
Given the expected interaction rate in each brick, a coarse
electronic detector is enough (interesting synergy with the
segmented magnetic detector)
Good results not only in the momentum and charge
measurement for mip, but also for electrons
The needed R&D, but for the magnetic field, is not a real
issue: a single brick is a self-consistent detector
e±, m±, ±
• The R&D on the different detector techniques is in progress
• The main issue is “how to magnetize large instrumented volumes”
• Exploit as much as possible the synergy among different techniques (i.e. MECC and
segmented magnetized detector)
• Realistic estimats of the signal and background as a function of the neutrino energy
• Realistic cost estimate not only of the detector but also of the accelerator complex
Near detector
(taken from A. Blondel conclusion @KEK)
Set-up a generic simulation of a near detector
Define a series of potential detector geometries to run on near
detector
-- dedicated purely-leptonic detector for absolute fluy
-- quasi-elastic , pi, pi0 detector with variable targets (a la T2K
ND280)
-- charm detector for Nufact
Carry out physics studies needed for the ISS report:
1.
Study flux normalisation through:
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Use quasi-elastic and elastic interactions to determine neutrino
spectrum
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Reconstruct muon polarization from spectrum
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Sensitivity for cross-section measurements: low energy?
5.
Determination of charm: remember this is main background for
golden channel!
6.
….suggestions ….
Conclusion
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Systematics are a crucial issue. They seem to be the critical
parameter in comparing “conventional beams” and BB operating with a
1Mton detector. Extremely important also at a NuFact
The water Cerenkov performances are solid, being based on real data
provided by several experiments
Gigantic LAr detectors need a proof of principle: many activities
under way
The technology for a segmented magnetized detector is not an issue.
More simulation and a more realistic reconstruction program are
needed to assess the physics reach
The MECC technique profits of the ongoing activity for the OPERA
experiment. Possible (an welcome) synergy with other techniques for
the electronic detector
How to magnetize large volumes and which is the maximum achievable
field is a crucial item. Depending on this item the physics reach of a
NuFact can strongly change. E.g. if only a “standard” magnetized iron
detector is feasible, only the golden channel can be exploited!
Outlook
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Study the performance of a stainless steel target
Detailed study of the way how to magnetize the detector
Define a realistic baseline for the e/p discriminator: its
choice depends on the total target mass, the TT width (i.e.
how many evts per brick), the costs, …
Finalize the electron analysis: the e/p separation and the
charge reconstruction
Check the sensitivity to the “golden” (the muon threshold
is at 3 GeV!)
A full simulation of neutrino events is mandatory in order
to evaluate the oscillation sensitivity and provide the input
for GLOBES
We plan to perform a first exposure of a MECC on a
charged beam at CERN this year
considerable noise reduction can be obtained
by gas amplification