neutrino2004 - paris, june 14-19 2004a.tonazzo – machine r&d towards a neutrino factory /1...
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Neutrino Paris, June A.Tonazzo – Machine R&D towards a Neutrino Factory /3 Target and collection Achieve intense muon beam by maximizing production of + and - Soft pion production –E910 measurements available –HARP cross-section results awaited! (talk by J.J.Gomez-Cadenaz tomorrow) High Z material Sustain high power (4 MW) –Solid target is not adequate Optimize pion capture Neutrino Factory Targetry concept: Hg jet continuous flow target Pion focusing magnetic system –EU: horn –US: 20T SC solenoidTRANSCRIPT
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 1
Machine R&D towards a Machine R&D towards a Neutrino FactoryNeutrino Factory
with focus on awith focus on a
Muon Ionization Cooling ExperimentMuon Ionization Cooling Experiment
Alessandra TonazzoUniversità Roma Tre and INFN Sez. Roma III
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 2
Towards a Neutrino Factory: the challengesTowards a Neutrino Factory: the challenges
• Target and collection– High + and - yield– Sustain high power– Capture as many produced
pions as possible
• Muon cooling– Reduce +/- phase space
to capture as many muons as possible in an accelerator
• Muon acceleration– Has to be fast, because
muons are short-lived !
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 3
Target and collectionTarget and collection
Achieve intense muon beam by maximizing production of + and -• Soft pion production
– E910 measurements available– HARP cross-section results awaited!
(talk by J.J.Gomez-Cadenaz tomorrow)
• High Z material• Sustain high power (4 MW)
– Solid target is not adequate• Optimize pion capture
Neutrino Factory Targetry concept:• Hg jet continuous flow target• Pion focusing magnetic system
– EU: horn– US: 20T SC solenoid
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 4
Pion collectionPion collection
2.2 GeV4 MW
Protons
Current of 300 kA
B1/RB = 0
The CERN magnetic horn for pion collection
Prototype built at CERN
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 5
Hg jet targetHg jet target• Continuous flow
free Hg jet– Tilted w.r.t. incoming proton
beam direction– Intense solenoidal B field to
capture low pt pions
• Key issues:– To what extent will the jet
disperse due to rapid energy deposition by intense proton pulse ?
– To what extent will magnetic forces perturb the flow of the jet into the magnet and affect the possible dispersal of the jet by the beam ?
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 6
Target: Hg jet testsTarget: Hg jet testsE951
•1 cm•v=2.5 cm/s•24 GeV 4 TP p beam•No B field
CERN/Grenoble•4 mm•v=12 m/s•No p beam•0,10,20T B field
Hg jet dispersal properties :• proportional to beam intensity• velocities ~½ times that of “confined
thimble” target• largely transverse to the jet axis • delayed 40 ms
• The Hg jet is stabilized by the 20 T B field• Minimal jet deflection for 100 mrad angle
of entry • Jet velocity reduced upon entry to B field
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Participating Institutions1) RAL2) CERN3) KEK4) BNL5) ORNL6) Princeton University
Proposal to test a 10m/s Hg Jet in a 15T Solenoid with an Intense Proton Beam
Target & collectionTarget & collection
Installation and commissioningat CERN by April 2006
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Reduction of Reduction of emittance emittance
The muon beam emittance must be reduced for injection into the acceleration system• Energy spread ► phase rotation• Transverse emittance ► cooling
AcceleratoAccelerator acceptance
R 10 cm, x’ 0.05 rad rescaled @ 200 MeV
and after focalization
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 9
Muon ionization coolingMuon ionization cooling
principle reality (simplified)
Never realized in practice !A realistic prototype should be built and proven to be adequate to the Neutrino Factory requirements.
reduce pt and pl
increase pl
heating
Stochastic cooling is too slow. Frictional cooling is only for +.A novel method for + and - is needed: ionization cooling
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 10
Muon Ionization Cooling ExperimentMuon Ionization Cooling ExperimentAims:• Show that it is possible to
design, build and operate a section of cooling channel capable of giving the desired performances for a Neutrino Factory
• Place it in a muon beam and measure its performances in a variety of operating modes, thereby investigating the limits and practicality of cooling
• Proposal submitted to RAL on Jan.10 2003
• Approval “strongly recommended” by Review Panel (May 20, 2003)
• Scientific approval from CCLRC chief executive (Oct 24, 2003)
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 11
MICE goalsMICE goals Build a section of cooling channel long enough to provide measurable
cooling (10% reduction of transverse emittance) and short enough to be affordable and flexible
Measure: 1) transverse emittance reduction with 0.1% precision2) transmittance of the channel
►Delicate integration of accelerator and particle detector physics !►Never done before !
Difficulty: standard emittance measurement barely reach the required precision Solution: Single particle measurement
–Measure track parameters before/after cooling channels–Reject non-muon background (undecayed s, electrons from s)
•The advantages:–Separate measurement of transmittance and emittance variation–A precision on (T
in-Tout) <10-3 can be achieved
•The challenge:–The measurement should not affect the cooling
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MICE setup: cooling + diagnosticsMICE setup: cooling + diagnostics
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 13
MICE cooling channelMICE cooling channel
•
• High gradient reacceleration– 10% reduction of muon emittance for 200 MeV muons requires ~20MV RF
• Challenge: integration of these elements in the most compact and economic way
• 3 Liquid Hydrogen absorbers
• 8 cavities 201MHz RFs, 8MV/m
• 5T SC solenoids
0
2
32 2)014.0(11XmEEds
dEdsd nn
Minimize heating term:•Absorber with large X0
•SC solenoid focusing for small T
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 14
RF module(Berkeley, Los Alamos, JLAB, CERN, RAL)
MICE cooling channel R&DMICE cooling channel R&D
LH2 window(IIT, NIU, ICAR)
First cavity has been assembled
Be window to minimize thickness
The challenge:Thin windows + safety regulations
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 15
MICE cooling channelMICE cooling channelBeam properties Quantities to be measured
Curves for 23 MV, 3 full absorbers, particles on crest
cooling effect at nominal input emittance ~10%
Equilibrium emittance
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 16
MICE: Emittance measurementMICE: Emittance measurement
Each spectrometer measures 6 parameters per particle x y t x’ = dx/dz = Px/Pz y’ = dy/dz = Py/Pz t’ = dt/dz =E/Pz
2'
''2'
''2'
'2
'2
'''2
...........................
............
............
............
t
tyy
txx
ttt
yty
xtxyxxxtxyx
M
2''
4
'''6
)det(
)det(
yxyxD
tyxytxD
M
MEvaluate emittance with: Compare Compare in in with with outout
Simulation of a muon traversing MICE
Determines, for an ensemble (sample) of N particles, the moments:Averages <x> <y> etc… Second moments: variance(x) x
2 = < x2 - <x>2 > etc… covariance(x) xy = < x.y - <x><y> >
Covariance matrix M
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 17
Spectrometer: requirements and errorsSpectrometer: requirements and errorsMeasurements• 10% emittance reduction measured to 1% absolute errors <0.1%• Resolution on all measured parameters better than 10%
Statistical• 105 muons (T
in-Tout) < 10-3 (in ~ 1 hr)
Systematic• Description of apparatus• Systematic differences between in/out spectrometers• Transport: wrong particles with different kinematics will spoil the
measurements– Muon in … muon out / and /e rejection at < 1% level
Robustness against harsh environment– Noise from RF cavities– Background– Intense magnetic fields
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 18
MICE TrackerMICE TrackerAlternative option:
TPC with GEM readout (TPG)Baseline option:
Scintillating fiber tracker
5 planes of Sci-FiWith double layer.0.35 X0 per layer
The prototype
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 19
MICE Tracker performanceMICE Tracker performanceA typical cosmic ray event
Measured and expected efficiencies
Point resolution ~440 m
Light yield
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 20
MICE: Particle IDMICE: Particle ID• Upstream:
– TOF hodoscopes with 10m path, 70 ps resolution
– Cherenkov / separation at better
than 1% at 300 MeV/c
• Downstream:0.5% of s decay in flight:
need electron rejection at 10-3 to avoid bias on emittance reduction measurement– TOF hodoscope– Aerogel Cherenkov
(n=1.02, blind to s)– Calorimeter for MIP vs
E.M. Shower
Ckov Cal
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 21
MICE at RALMICE at RAL
Site Proposed for MICE Plant
Proposed route for services
Alternative route for services
Proposed site for controls & control room (presently the cable store and under the ISIS control room).
Proposed new linac cooling plant room
Hall has been emptied and preparation to host the experiment begun
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 22
- STEP I: spring 2006
STEP II: summer 2006
STEP III: winter 2007
STEP IV: spring 2007
STEP V: fall 2007
STEP VI: 2008
MICE installation phasesMICE installation phases
2006
2007
2008
Subject to availability of funds…
……
……
……
……
……
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 23
Muon accelerationMuon acceleration• Previous accelerator
scheme: LINAC + Recirculating Linear Accelerator (RLA)– Very costly: need high RF
gradient to limit losses from muon decay
• Proposed solution: use Fixed Field Alternating Gradient (FFAG) accelerator – Repetition rate can be
raised >10 times faster than in ordinary synchrotrons
New US Scheme
Japan Scheme
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 24
Muon acceleration: FFAGMuon acceleration: FFAG
• Latest ideas in US have lead to the invention of a new type of FFAG (“non-scaling FFAG”) – interesting for more than just Neutrino Factories– may require a demonstration experiment (plans are developing)
• R&D in Europe is just starting
Perhaps the different concepts are merging to produce something better ??
Much progress in Japan with the development and demonstration of large acceptance FFAG accelerators
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 25
Why we are optimistic/enthusiastic – US perspective:
Note: In the Study 2 design roughly ¾ of the cost came from these 3 roughly equally expensive sub-systems.
New design has similar performance to Study 2 performance but keeps both + and - !
(S.Geer - CERN MW ws April 2004)
Good hope for improvement in performance and reduction of cost!
We are working towards a “World Design Study” We are working towards a “World Design Study” with an emphasis on cost reductionwith an emphasis on cost reduction
Neutrino2004 - Paris, June 14-19 2004 A.Tonazzo – Machine R&D towards a Neutrino Factory / 26
Summary and outlookSummary and outlookThe construction of a Neutrino Factory poses several
stimulating challenges
• Target and collection– Magnetic horn prototype built at CERN
– Complete target test experiment proposed and approved
• Muon cooling– International Muon Ionization Cooling Experiment at RAL
• Acceleration– The FFAG solution is progressing both in Japan and in the US
• Enthusiastic R&D is ongoing, and a lot has already been accomplished