Detector R

1
Detector RD status and priorities

• Paolo Strolin
• NUFACT05
• June 26, 2005

Main issues in launching the Scoping Study on a
n-factory and super-beam facility
Low-Z Tracking Calorimetry Magnetised Iron
Spectrometers Water Cerenkov Liquid Argon
TPCEmulsion Cloud Chamber
Some of the detectors also for astro-particle
physics
2
To be carried out in parallel for detector
optimisation
3
Where do we stand with (conceptual)
beam-detector optimization for b-beams and
n-factory beams?
was the main topic of the talk on Neutrino
detectors for future neutrino beams by S.
Ragazzi
More work to be done Also emerged from WG reports
and talks on specific detectors One of the
issues is .
4
n-factories searching for wrong sign muons

• Background from
• wrong charge assignment to leading muon
• reduced with momentum cut and track fit cut
• - m from p-decay or from heavy quark decay
  reduced with isolation cut
• (e.g. require minimum pt of the leading muon with
  respect to hadron jet)
• Momentum tracking threshold and resolution
• affect sensitivity, degeneracy and possibility to
  lower En (talk by P. Huber)

More work to be done for detector
optimisation ? Tune Monte Carlo on the basis of
existing detectors Assume baseline design, in
collaboration with engineers Simulate
detectors Detector optimisation Compare different
detector concepts and designs ....
5
This talk Detector RD status and priorities
Some of the progress which has been done Main
issues on detector RD and design (in partial
overlap with WG reports)
6
Low-Z Tracking Calorimetry
7
NOnA in off-axis NuMI beam
Main issue mass 10 x MINOS ? new technologies
to reduce cost

• Observe q13
• Liquid (plastic in MINOS) scintillator
• Avalanche Photo Diodes (APD) (PMTs in MINOS)
• higher QE ? longer strips ? less readout
  channels
• Totally Active liquid scintillator Detector
  (TASD) now retained
• No need of underground location (live-time 100
  s/year)
• Active shielding from cosmic rays foreseen
  (cheaper than passive overburden)
• Detector to be completed in late 2011 if funding
  begins in late 2006

8
The totally active NOnA detector
30 kton mass 24 kton liquid scintillator, 6 kton
PVC 4-6 cm (x, y, z) segmentation Progress in the
mechanical design and in the construction
methods details are taking shape Experience
with trackers potentially useful also for
magnetised iron spectrometers
9
Magnetised Iron Spectrometers
10
A Large Magnetic Detector (LMD) for a n Factory

• Iron calorimeter,
• plastic scintillator rods as active detector
• Magnetised at B 1 T
• ? see wrong sign
• muons from ne-nm
• Conventional technique, but 40 kton mass (one
  order of magnitude gt MINOS)
• Only concept available practical problems must
  be addressed to assess the feasibility
  (mechanics, magnet design, . ) technical
  support needed
• More simulation work to be done to understand and
  optimise the performance

11
Making a torus bigger than MINOS

• From the talk by J. Nelson
• the detector is feasible
• large area toroidal fields can by extrapolated
  from MINOS design (thicker plates for large
  planes)
• can now make an affordable large area
  scintillator readout with NOvA technology

Engineering work must be done on mechanics,
magnet design, . Studies required to optimise
the performance of the detector (tracking
threshold, resolution, background rejection,
e-ident, ) Make direct use of the experience
with MINOS
12
A 50-100 kton magnetised iron detector à la
Monolith
Monolith concept by P. Picchi and collaborators
taken up for the India-based Neutrino
Observatory (INO) (talk by N.K. Mondal) ?
atmospheric neutrinos, in future n-factories
Investigations started with Monolith to be taken
up again detector performance studies,
comparison horizontal vs vertical iron plates,
design optimisation, comparison with other
detectors, ..
13
Water Cerenkov
14
Comparison of Hyper-K and UNO .vs. Super-K
IMB / KamiokaNDE ? Super-K ? Hyper-K / UNO In
each generation one order of magnitude increase
in mass
Super-K Hyper-K UNO
Total mass kton 50 2 x 500 650
Fiducial mass kton 22.5 2 x 270 440
Size F 41 m x 39 m 2 x F 43 m x 250 m 60 m x 60 m x 180 m
Photo-sensor coverage 40 40 ? 40 (5 MeV threshold) ? 10 (10 MeV threshold)
PMTs 11,146 (20) 200,000 (20) 56,650 (20) 15,000 (8)
A large fraction ( ½ or more) of the total
detector cost comes from the photo-sensors With
present 20 PMTs and 40 coverage for the full
detector, the cost of a Mton detector could be
prohibitive
15
Increasing the detector mass

• better energy containment
• larger effective granularity of photo-sensors
• (due to larger average distance of photo-sensors
  from event vertex)
• Main issue
• RD on photo-sensors, in collaboration with
  industries
• to improve
• cost
• production rate affects construction time and
  may give serious storage problems
• performance
• time resolution (? n vertex), single photon
  sensitivity (? ring reconstruction)

16
RD on photo-sensors for Water Cerenkov

• PMTs
• Automatic glass manufacturing not the way to
  reduce cost and speed-up production rate
  required quantities still small compared to
  commercial PMTs
• Collaboration with industries (Hamamatsu,
  Photonis, . )
• - very important for an effective RD
• - competition could stimulate ways for cost
  reduction
• Are 20 PMTs optimal? Global cost PMTglass
  sphere , risk of implosion,
• What is the optimal photo-sensor coverage?
  Function of physics, energy, ..
• New photo-sensors
• Hybrid Photo-Detectors (HPD) by ICRR Tokyo -
  Hamamatsu
• .

17
Principle of HPD and comparison to PMTs

• Simpler structure ? lower cost
• no dynodes
• Single photon sensitivity
• from large gain at the first stage
• Good timing resolution (1ns)
• PMT-SK 2.3 ns (mainly TTS)
• Wide dynamic range (gt1000 p.e.)
• determined by AD saturation
• Challenging HV (20 kV)
• ? focus onto a small AD (5mmf)
• Smaller Gain
• highly reliable low-noise amplification and
  readout needed

HPD
photon
photocathode
avalanche diode (AD)
Total Gain 105
PMT-SK
dynodes
TTS (Transit Time Spread)
18
RD on HPDs
RMS 0.8 ns

• Proof of principle achieved with 5 prototype
• New results 13 prototype tested with 12 kV
• gain 3x104, single photon sensitivity, timing
  resolution 0.8 ns (2.3 ns with PMTs),
• good gain and timing uniformity over
  photo-cathode area
• Next steps
• - new bulb 12kV ? 20kV, giving wider effective
  photo-cathode area and higher gain
• - higher gain from AD, low-noise preamp, readout

19
An ancestor of hybrid PMTs

• P.h. resolution elimination of single p.e. noise
  (for DUMAND)
• Patented by Philips (Photonis)
• Copied by INR, Moscow
• ? the QUASAR
• Large investment by Philips/Photonis
• made 30
• 200 QUASARs (15) operating for many years in
  Lake Baikal
• No ongoing production

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Liquid Argon Time Projection Chamber

• Two target mass scales for future projects
• 100 ton as near detector in Super-Beams (not
  discussed here)
• 50-100 kton for n oscillation, n astrophysics,
  proton decay

21
To reach 50-100 kton mass
ICARUS T300 module 0.3 kton, 1.5 m drift, 1 ms
drift time The present state of the art ICARUS
a 2 kton detector to be operated underground at
Gran Sasso

• Cryogenic insulation requires minimal
  surface/volume
• ? A single very large cryogenic module with
  aspect ratio 11
• Do not pursue the ICARUS multi-module approach
• Longer drift length, to limit the number of
  readout channels
• Two approaches
• 3 - 5 m drift length, with readout as in ICARUS
• Very long drift length ( 20 m) and Double
  Phase readout
• (amplification in Gas Argon to cope with signal
  attenuation)
• In both cases, the signal attenuation imposes
  a high LAr purity ( 0.1 ppb O2 equiv.)

22
Double-Phase (Liquid Gas) readoutBasic
references Dolgoshein et al. (1973) Cline,
Picchi ... et al. (2000)Tested on the ICARUS 50
l chamber

• Charge attenuation after very long drift in
  liquid compensated
• By charge amplification near anodes in gas phase

• With 2 ms e-lifetime,
• the charge attenuation in 10 ms is e-t/t 1/150
• (original signal 6000 e- /mm for a MIP in LAr)
• Amplification in proportional mode (x 100-1000)
• on thin wires (f 30 mm) with pad readout or
  ..
• Diffusion after 20 m drift ? s 3 mm
• gives a limit to the practical readout granularity

23
A Liquid Ar TPC for the off-axis NuMI beamLetter
of Intent, hep-ex/0408121 (2004)

• A detector for n oscillation
• Readout as in ICARUS, with detector subdivided in
  readout sections
• 15-50 kton 0.5-1.5x102 extrapolation in mass
  from ICARUS T300
• 3 m max drift length (1.5 m in ICARUS T300) with
  E 0.5 KV/cm
• Surface location foreseen (operated only with n
  beam)
• Progress in the engineering design (talk by S.
  Pordes)

24
A 100 kton Liquid Argon TPC with Double-Phase
readoutA. Rubbia, Proc. II Int. Workshop on
Neutrinos in Venice, 2003

• A detector for n oscillation, n astrophysics,
  proton decay
• A single cryogenic and readout module
• 20 m drift length, 10 ms drift time with as much
  as 1 KV/cm (0.5 in ICARUS T300)
• Liquid Ar at boiling temperature, as for
  transportation and storage of Liquefied Natural
  Gas
• 3x102 extrapolation in mass from ICARUS T300

25
Ongoing studies and RD(from A. Rubbia)

• Electron drift under high pressure (p 3 atm at
  the bottom of the tank)
• Charge extraction, amplification and imaging
  devices
• Cryostat design, in collaboration with industry
• Logistics, infrastructure and safety issues
• (in part. for underground sites)
• Tests with a 5 m column detector prototype
• ? 5 m long drift and double-phase readout
• ? Simulate 20 m drift by reduced E field and
  LAr purity
• Study of LAr TPC prototypes in a magnetic field
  (for n Factory)
• tracks seen and measured in 10 lt prototype

26
First operation of a 10 litre LAr TPC in a
B-field(talk by A. Rubbia)
27
Tentative layout of a large magnetized Liquid
Argon TPC(talk by A. Rubbia)
He refrigerator
Phase separator
Magnet solenoidal superconducting coil
LHe
Two phase He
Gas Ar
Charge readout plane
Electronic racks
E 3 kV/cm
Liq Ar
Extraction grid
B 0.1?1 T
E 1 kV/cm
UV Cerenkov light readout PMTs and field
shaping electrodes
Cathode (- HV)
LHe Cooling Thermosiphon principle thermal
shield LAr
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The Emulsion Cloud Chamber (ECC) for ne? nt
appearance at n Factories

• ne? nm (golden events) and ne? nt (silver
  events) to resolve q13 - d ambiguities
• Pb as passive material,
• emulsion as sub-mm precision tracker
• unique to observe t production and decay
• Hybrid experiment emulsion electronic
  detectors
• 1.8 kton OPERA target mass
• ? 4 kton at n Factory
• Scan events with a wrong sign muon
• x 2 increase of scanning power required
• OPERA is a milestone for the technique

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Summary (1) Low-Z Calorimetry

• nm- ne oscillations ? q13 in off-axis NuMI
  beam NOnA
• Evolution of a proven technique
• Main issue
• improve performance and reduce cost of trackers
• NOnA mass 10 x MINOS
• New technologies with respect to MINOS
• plastic ? liquid scintillator a totally
  active detector now chosen
• PMT ? Avalanche Photo Diodes (APD)
• Progress on trackers potentially useful also
  for
• magnetised iron sampling spectrometers or
• for calorimetry in view of other
  applications
• (maintain contacts with the collider community)

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Summary (2) Magnetised Fe Spectrometers

• Wrong sign m from ne ? nm oscillations at
  n-Factories
• Well proven technique
• Target mass 10 x MINOS
• Proceed from concepts towards a design
• Engineering work (mechanics, magnet design, . )
  must be done to assess the feasibility technical
  support needed
• Evaluate and optimise the performance of the
  detector
• (tracking threshold, resolution, background
  rejection, e-ident, )
• ? detailed detector simulations

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Summary (3) Water Cerenkov

• n oscillation , n astrophysics, proton decay
• Proven and successful technique, well known also
  in its limitations
• Super-K a large Water Cerenkov detector of
  which the performance
• has been simulated and observed
• Experience with experiments
• K ? Super-K ? Hyper-K/UNO/Frejus in each
  step mass x 10
• Main issue cost and production of photo-sensors
• ? collaboration with industries very
  important, to be supported
• ? are 20 PMTs optimal? Which is the optimal
  photo-sensor coverage?
• ? RD on new photo-sensors with adequate
  long-term stabilityreliability

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Summary (4) Liquid Argon TPC

• A beautiful detector for n oscillation , n
  astrophysics, proton decay.
• Broad energy range
• Tested at the scale of the 0.3 kton ICARUS T300
  module
• extrapolation in mass by two orders of
  magnitudes or more needed
• New features envisaged to reach 50-100 kton
• longer or much longer drifts, double-phase
  amplification and readout
• Experience accumulated for ICARUS, dedicated RD
  (results now available from 10 liter chamber in
  magnetic field, )
• Substantial RD required on various aspects,
  partly depending on the design parameters signal
  propagation and readout, HV and electric field
  shaping cryogenics, purification, operation in a
  magnetic field, civil engineering, safety and
  logistics, ..
• Proceed from concepts towards detector designs
• (without and with magnetic field)
• Location underground (availability and cost,
  more severe safety issues) or
• surface location (assess if adequate loss of
  events superimposed to cosmics)

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General conclusions
A lot of work is going on
Very interesting times for the scoping study and
for the future of neutrino physics Work done by
groups and collaborations Requires support by the
respective institutions The scoping study will
provide an important framework to exchange
knowledge, device strategies and best
collaborate Establish interactions with RD for
other purposes, e.g. for linear collider physics