1. Challenges of future accelerator-based
Neutrino Facilities
Introduction
Proton drivers
Target and Collection
Neutrino Factory challenges
muon cooling
acceleration (FFAGs)
Beta-Beam challenges
See NUFACT04 site:

2. leptonic CP & T violations
Where are we?
We know that there are three families of active, light neutrinos (LEP)
Solar neutrino oscillations are established (Homestake+Gallium+Kam+SK+SNO+KamLAND)
Atmospheric (nm -> ) oscillations are established (IMB+Kam+SK+Macro+Sudan+K2K)
At that frequency, electron neutrino oscillations are small (CHOOZ)
This allows a consistent picture with 3-family oscillations
q12 ~ Dm122~ eV q23 ~ Dm23 2~ eV q13 <~ 100
with several unknown parameters q13, d, mass hierarchy
leptonic CP & T violations
=> an exciting experimental program for at least 25 years *)
Where do we go?
*)to set the scale: CP violation in quarks was discovered in 1964
and there is still an important program
(K0pi0, B-factories, Neutron EDM, LHCb, BTeV….)
to go on for >>10 years…i.e. a total of >50 yrs.
and we have not discovered leptonic CP yet!
5. LSND ? ( miniBooNe)
This result is not consistent with three families of neutrinos oscillating, and is not supported
(nor is it completely contradicted) by other experiments.
If confirmed, this would be even more exciting
See Barger et al PRD

3. Atmospheric “wavelenght”

4. A Experiments to find q13 :
Road Map
A Experiments to find q13 :
search for nmne
--in conventional nm beam (MINOS, ICARUS/OPERA)
limitations: NC p0 background, intrinsic ne component in beam
-- in reactor experiments
--Off-axis beam (JHF-SK, off axis NUMI, off axis CNGS) or
--Low Energy Superbeam (BNL  Homestake, SPL Fréjus)
B Precision experiments to find CP violation
-- or to search further if q13 is too small
-- beta-beam and
-- Neutrino factory with muon decay storage ring
and
fraction thereof will exist .

5. Example: a series of facilities envisaged for CERN
As always in neutrino physics the event rate is a major concern
Most future facilities are based on a
High Intensity Proton source.
Example: a series of facilities envisaged for CERN

6. Fréjus underground lab.
CERN-SPL-based Neutrino SUPERBEAM
300 MeV n m Neutrinos
small contamination from ne (no K at 2 GeV!)
target!
Fréjus underground lab.
A large underground water Cerenkov (400 kton) UNO/HyperK
or/and a large L.Arg detector.
also : proton decay search, supernovae events solar and atmospheric neutrinos. Performance similar to J-PARC II
There is a window of opportunity for digging the cavern stating in 2008 (safety tunnel in Frejus)

7. -- Neutrino Factory -- CERN layout --
cooling!
1016p/s
target!
acceleration!
m/s = m/yr
m/yr _
m+  e+ ne nm
ne/yr
nm/yr
oscillates ne  nm
interacts giving m-
WRONG SIGN MUON
interacts
giving m+

8. CERN: b-beam baseline scenario
EU pride..
Nuclear Physics
SPL
target!
Decay ring
B = 5 T
Lss = 2500 m
SPS
Decay
Ring
ISOL target & Ion source
ECR
Cyclotrons, linac or FFAG
Foer politiska skael har jag laatit bli att skriva EURISOL och valt att skriva Nuclear Physics istaellet. Energin foer jonerna aer laangt ifraan helt fast-staelld. Gamma=150 foer Helium aer inte ett “magiskt” tal men det aer mest kraevande utifraan accelerator synpunkt saa daerfoer har jag koncentrerat mig paa detta I fortsaettningen.
Stacking!
Rapid cycling synchrotron PS
Same detectors as Superbeam !

9. The reference facility: J-PARC 0.75 MW at start, evolving
Nuclear and Particle
Experimental Facility
Materials and Life Science
Experimental Facility
Nuclear Transmutation
Neutrino to Kamiokande
3 GeV Synchrotron
(25 Hz, 1MW)
50 GeV Synchrotron
(0.75 MW)
Linac
(350m)
J-PARC = Japan Proton Accelerator Research Complex

10. Fermilab Proton Driver 8 GeV Superconducting Linac
Basic concept inspired by the observation (by Bill Foster) that $/GeV for SCRF has fallen dramatically
 Consider a solution in which H- beam is accelerated to 8 GeV in a superconducting linac and injected directly into the Main Injector
Attractions of a superconducting linac:
Many components exist (few parts to design vs. new synchrotron)
Copy SNS, RIA, & AccSys Linac up to 1.2 GeV
“TESLA” Cryo modules from 1.2  8 GeV
Smaller emittance than a synchrotron
High beam power simultaneously at 8 & 120 GeV
Plus, high beam power (2 MW) over entire GeV range
Flexibility for the future
Issues
Uncontrolled H- stripping
Halo formation and control
Cost

11. 8 GeV Linac Neutrino “Super- Beams” X-RAY FEL LAB Long-Pulse
Fermilab Proton Driver 8 GeV SC Linac: Other possible missions (from the mind of Bill Foster)
Damping Rings
for FNAL
With 8 GeV e+ Preacc.
1% LC Systems Test
VLHC at Fermilab
Neutrino
“Super-
Beams”
NUMI
Off-
Axis
SY-120
Fixed-Target
X-RAY FEL LAB
Anti-
Proton
8 GeV
neutrino
~ 700m Active Length
8 GeV Linac
Main
Injector
@2 MW
Long-Pulse
Spallation Source
Bunching
Ring
Recirculating
Linac for Neutrino Factory
& Neutrino Target
Neutrinos
to “Homestake”
Target and Muon Cooling Channel
Short Baseline Detector Array

12. Target !  4 MW of protons (i.e. 40 000 light bulbs!)
High intensity proton accelerators pose many challenges but certainly one of the most critical one is the
Target !
Typical Dimensions: L  30 cm, R  1 cm
 4 MW of protons (i.e light bulbs!)
into a big cigar….
it would immediately go to smoke.

13. Liquid Mercury Target R&D
Speed of Hg disruption
Max v  20 m/s measured
v//  3 m/s
(design calls for 20m/s)
1 cm
Protons
liquid jet of mercury
jet remains intact for more than 20 microseconds.

14. Liquid Mercury Target R&D
US scheme:
jet is inside a
very high field
tapered solenoid
(20 T max)
this was tested at the Laboratoire de Champs Intenses (Grenoble)
A. Fabich et al– CERN-BNL-Grenoble

15. Targetry: other ideas
Many difficulties: enormous power density  lifetime problems
Stationary granular target:
Replace target between bunches:
rotating solid target
Proposed rotating tantalum target ring
Densham
Sievers

16. Prototype built at CERN
Target & collection
The CERN magnetic horn for pion collection
Current of 300 kA
Prototype built at CERN p
Protons
2.2 GeV
4 MW
B = 0
B1/R
Major issue is resistance of horn material to combination
of shock, Joule heating & irradiation

17. Installation and commissioning
Target & collection
Proposal to test a 10m/s Hg Jet in a 15T Solenoid with an Intense Proton Beam
Participating Institutions
RAL
CERN
KEK
BNL
ORNL
Princeton University
aim:
Installation and commissioning
at CERN by April 2006

18. Hg-jet system Power absorbed in Hg-jet 1 MW Operating pressure 100 Bar
Flow rate 2 t/m
Jet speed 30 m/s
Jet diameter 10 mm
Temperature - Inlet to target 30° C - Exit from target 100° C
Total Hg inventory 10 t
Pump power 50 kW

19. Muon ionization cooling
Frictional cooling is only for m+
A novel method for m+ and m- is needed: ionization cooling
principle
reality (simplified)
reduce pt and pl with as little
heating as possible:
Hydrogen!
increase pl
fast acceleration
Never realized in practice !
A realistic prototype should be built and proven to be adequate to the Neutrino Factory requirements.

20. MICE setup: cooling + diagnostics

21. Operation of RF cavities at high gradient in magnetic field
Dark current backgrounds measured
on a 805 MHz cavity in magnetic field!
with a 1mm scintillating fiber at d=O(1m)
This will be also a source of backgrounds for MICE:

22. RF cavity (800 MHz) at Fermilab
being pushed to its limits (35 MV/m)
to study dark current emission in magnetic field. Sees clear enhancement due to B field.
Various diagnostics methods
photographic paper, scintillating fibers
Microscope 
BCT and solid state counters
have demonstrated this and allowed precise
measurements
Real cavities will be equipped with Be windows
which do not show sign of being pitted contrary to Cu

23. MICE cooling channel R&D
The challenge:
Thin windows + safety regulations
RF module
(Berkeley, Los Alamos, CERN, RAL)
LH2 window
(IIT, NIU, ICAR)
First cavity
Be window to minimize thickness

24. MICE installation phases-
STEP I
2006
STEP II
STEP III
2007
STEP IV
STEP V
2008
STEP VI

25. Muon acceleration
Previous accelerator scheme: LINAC + Recirculating Linear Accelerator (RLA)
Very costly and rigid use.
Proposed solution:
Fixed Field Alternating Gradient (FFAG). a new type of accelerator with B-field shaped as rk
-->particles can be kept and accelerated over a range of energies of ~factor 3.
Japan Scheme
New US Scheme

26. Muon acceleration: FFAG
Much progress in Japan with the development and demonstration of large acceptance FFAG accelerators
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 (e.g. from SPL to 20 GeV?)
require a demonstration experiment (PRISM, electron prototype)
Perhaps US & Japanese concepts are merging to produce something better ??

27. $$$$$ … COST … $$$$$
USA, Europe, Japan have each their scheme for Nu-Fact.
Only one has been costed, US 'study II' and estimated (2001) ~2B$.
The aim of the R&D is also to understand if solutions
could reduce cost in half.
+ detector: MINOS * 10 = about 300 M€ or M$
Neutrino Factory CAN be done…..but it is too expensive as is.
Aim of R&D: ascertain challenges can be met + cut cost in half.

28. NUFACT 2004: cost can be reduced by at least 1/328
Why we are optimistic:
In the previous design ~ ¾ of the cost came from these 3 equally expensive sub-systems. New design has similar performance to Study 2 performance and keeps both m+ and m- !
(RF phase rotation)
NUFACT 2004: cost can be reduced by at least 1/3
= proton driver + 1 B €
MAYBE the Neutrino Factory is not so far in the future after all….
We are working towards a “World Design Study” with an emphasis on cost reduction.
S. Geer:

29. Beta beam Challenges
1. Intense production of ions, in particular + emitters (18Ne)
2. Clean acceleration: life time is much longer than muons but the decays produce activation in the rings)
3. Stacking in the storage ring

30. 6He production by 9Be(n,a)
Converter technology: (J. Nolen, NPA 701 (2002) 312c)
Layout very similar to planned EURISOL converter target aiming for 1015 fissions per s.

31. Production of b+ emitters
Spallation of close-by target nuclides: 18,19Ne from MgO and 34,35Ar in CaO
Production rate for 18Ne is 1x1012 s-1 (with 2.2 GeV 100 mA proton beam, cross-sections of some mb and a 1 m long oxide target of 10% theoretical density)
19Ne can be produced with one order of magnitude higher intensity but the half life is 17 seconds!
A PULSED souce could be realized by ECR (P.Sortais Moriond 2003)
Baade Neon och helium aer producerat med EURISOLs “lilla” target station foer 100 kW. Igen, foer neon har vi taenkt oss tre targets efter varandra.

32. From dc ions to very short bunches
2.2 ms t B PS
SPS
2 x 1.1 ms to decay ring (4 bunches with few ns)
PS: 1s flat bottom with 8 (16) injections. Acceleration in ~1s to top PS energy
Target: dc production during 1 s.
60 GHz ECR: accumulation for 1/8 (1/16) s ejection of fully stripped ~20ms pulse batches during 1s.
RCS: further bunching to ~100 ns Acceleration to ~300 MeV/u (16) repetitions over 1s.
SPS: injection of 8 (16) bunches from PS. Acceleration to decay ring energy and ejection of bunches. Repetition time 8 s.
7 s
Post accelerator linac: acceleration to ~100 MeV/u. 8 (16) repetitions over 1s.

33. STACKING is necessary to ensure duty cycle less than 10-3
inject off energy
(using e.g. dispersive section)

34. Summary
The construction of future neutrino facilities poses many stimulating challenges
Enthusiastic R&D is ongoing, and a lot has already been accomplished (despite all the difficulties related to lack of funding) -- much more is needed!
Many of these facilities offer other a large range of physics interests ranging from nuclear physics to rare muon decay and neutrinos -- AND… LHC upgrade…
The long term goal, LEPTONIC CP VIOLATION, makes the effort highly worthwhile