The technical challenge of

1
The technical challenge of Superbeams
and Neutrino Factories
H. Haseroth, CERN
2
Question to the organisers I presume that I
should rather give an introductory talk for the
newcomers.
Answer That is part of it. But you should
really present the goals of the WG, the tasks
conveners have set up for this year and beyond,
the conclusions you are aiming at for
the concluding sessions at the end of the week.
Wow !!!
this looks like the most scientific approach,
with a laptop below
3
Layout of talk
1) Format of WG3 2) Goals of the WG Tasks the
conveners have set up for this year
and beyond
Ill skip this
3) The conclusions you are aiming at for the
concluding sessions at the end of the week
(I leave this to my co-conveners at the end of
the week)
4) Short introductory talk Basics of
Neutrino Factory and Superbeam 5) Specific
problems, activities (which should be) going on
4
Format of WG3 In the past NuFacts we have had
practically always mini-conferences instead of
a real working group. We listened to nice
presentations, but the disadvantage was
frequently that there was not enough time for
questions, comments, new ideas, which can develop
in a discussion. Only coffee breaks etc. could
be used for that purpose and then the audience
was naturally somewhat limited.
5
This time we have tried to move away from this
scheme. We still have a certain number of
(shorter!) presentations, but in addition we have
focus sessions, animated by moderators, who
will try to provoke discussions on certain
subjects Subject Moderator Proton
driver Chris Prior Targetry Peter
Sievers Cooling (incl. rings etc.) Bob
Palmer FFAGs and acceleration Yoshi Mori World
wide design study Ken Long
6
Session Chair 1 Koji
Yoshimura 2a Grahame Rees 2b
Dan Kaplan 2c Moderator-Peter
Sievers 3A WG1 assignment 3b
Rolland Johnson 4a Rick Fernow 4b
Moderator-Chris Prior 5
Moderator-Bob Palmer 6a WG1 or 2
assignment 6b Shinji Machida 7
Alan Bross 8a Moderator-Ken Long 8b
Roland Garoby 9a
Moderator-Yoshi Mori 9b Speaker-Roland
Garoby
7
Goals(1) of WG3 (my humble private opinion) Get
more participation and help (money people)
for Targetry Enhance comparison between
solid and liquid targets. Join the nTOF11
(high power target experiment at CERN
collaboration ! Cooling (incl. rings
etc.) Optimum for nufacts and possibilities for
muon colliders. Join MICE ! FFAGs and
acceleration Find most economical
solution Join the e-model collaboration !
8
Goals (2) of WG3 (my humble private
opinion) Related to our focus sessions Get
more discussions going and get (hopefully) more
new ideas Proton driver Define energy or
define what needs still to be explored to define
it ! World wide design study Get together
to draft a plan and do the follow-up
9
Short introductory talk Basics of Neutrino
Factory and Superbeam No Superbeam without
targets and horn proton driver target collection c
ooling acceleration decay ring

10
Reminder How do we get neutrinos?
Well, they are everywhere and lots of
them Estimates remnant neutrinos (2K) around
150 cm-3 Solar neutrino flux 5x106/cm2s Reactor
flux 1012 - 1013/cm2s beta decay pi
decay muon decay
Wanted

1. many
2. at reasonable energy

11
What are the different possibilities?
Beta-beam Superbeam Neutrino factory
12
What is a Beta-beam? See next talk!
What is a Superbeam?
A Superbeam is a conventional ?-beam where the
?s are produced by ? (and K) decay but at a much
higher intensities
What is a Neutrino Factory?
A Neutrino Factory is a machine where the ?-beam
is produced by ? decay, which are in turn
produced by the decay of ?s. The ? beam is of
good quality and may open the way to ? colliders
(the ultimate high energy for lepton colliders)
Very schematic layout
Superbeam
Target
Neutrinos
Electrons
Accelerated Muons
Protons
Pions
Muons
Neutrinos
13
now 3.5 GeV
cooling!
target!
acceleration!
After Blondel
14
R B Palmer
15
Scott Berg Study 2 A
16
CERN 3-stage approach(for the proton driver)

• Stage 1 3 MeV test place
• Þ development and test of linac equipment, beam
  characterization

• Stage 2 Linac4
• New linac replacing the present injector of the
  PS Booster (Linac2)
• Front-end of the future SPL
• Þ improvement of the beams for physics (higher
  performance and easier operation for LHC, ISOLDE
  etc.)

• Stage 3 SPL
• New injector for the PS, replacing the PS Booster
• New physics experiments using a high proton flux
• Þ improvement of the beams for physics and
  possibility of new experiments

17
(No Transcript)
18
Fréjus underground lab.
19
Phase rotation
Phase rotation in the CERN scheme is achieved
with rf cavities operating at 88 MHz. The
American scheme was using induction linacs, now
rf cavities to first bunch and then rotate the
beam. In both cases one lets the muon beam
generated via the very short (1 ns rms) proton
bunch spread out in the longitudinal direction
and use the corresponding time-position
correlation to correct the energy of the muons
with a time-varying electric field.
20
Cooling / Cooling Rings
To perform cooling, the beam is sent through
liquid hydrogen absorbers, reducing the
transverse and longitudinal momenta. Subsequent
reconstitution of the longitudinal momentum
occurs with RF cavities. Basically the cooling
channel is a linear accelerator with liquid
hydrogen absorbers. The cooling channel will be
fairly long and expensive, hence the interest in
ring coolers, where cooling is done over many
revolutions.
21
Acceleration with RLAs or FFAGs
After the cooling the muons have to be
accelerated to energies between 20 and
50 GeV. Normal synchrotrons are too slow and the
decay losses of muons would not be tolerable (the
muons life time is only 2.2 ?s). So-called
recirculating linacs (RLA) were advocated as a
good compromise between cost and speed. Now it
seems that FFAGs are more cost effective.
One interesting proposal should nevertheless be
mentioned here the possible use of a rapidly
pulsed synchrotron (D. Summers), which seems
feasible by making use of the fairly low
repetition rate, at least in the US scheme.
22
some specific problems Specific problems,
activities (which should be) going on, and WG3
goals
23
Problems Intensity related proton driver,
target, cooling, acceleration Mains power
related proton driver, cooling,
acceleration Cost related everything Techn
ology related (somewhat subjective) target,
collection, cooling, acceleration
24
Well, let us see where we have no problems
?
Target for one shot
25
Alain Blondel
26
Target Horn
27
Target

• Distribute the energy deposition over a larger
  volume
• Similar a rotating anode of a X-ray tube

rotating toroid
toroid magnetically levitated and driven by
linear motors
R.Bennett, B.King et al.
solenoid magnet
toroid at 2300 K radiates heat to water-cooled
surroundings
proton beam
28
Target
Target Module with jumpers
The SNS Target Station
Outer Reflector Plug
Target Inflatable seal
Core Vessel water cooled shielding
Core Vessel Multi-channel neutron guide flange
Moderators
29
Target
30
Target
31
Target / energy of the proton driverStephen
Brooks summary

• So far, it appears that a 10-30GeV proton beam
• Produces 60 more pions per p.GeV
• in a more focussed angular distribution
• with 40 less rod heating
• than the low-energy option
• BUT the useful yield is crucially dependent on
  the capture system

• While 30GeV may be excellent in terms of raw pion
  yields, the pions produced are increasingly lost
  due to
• Large transverse momenta (above 10-20GeV)
• A high energy spread, outside the acceptance of
  bunching systems (above 6-10GeV)
• This work suggests the optimal energy is around
  6-10GeV, providing a 50 yield improvement over
  2.2GeV

32
Now approved as nTOF11
Target

• Participating Institutions
• RAL
• CERN
• KEK
• BNL
• ORNL
• Princeton

33
Pump Systems
Target

• EM centrifugal pump
• or
• Hydraulic piston pump

34
15 T pulsed solenoid
Target

• 3rd coil production completed
• Integration into cryostat starts
• Testing scheduled in summer 2005 at MIT

P.Titus, MIT
35
Secondary particle yield
Target

• momentum p 24 GeV/c
• 4 bunches within 8 PS buckets at our discretion
• tpulse 0.5-2 microseconds
• tbunch50ns full length, peak-to-peak 250 ns
• lt 7 TP per bunch, total intensity lt 28 TP/pulse
• spot size at target lt2 mm r.m.s.

Pump-Probe method for cavitation studies and
secondary meson yield
36
Target and horn (needed for Superbeam)
37
Cooling MICE
38
Cooling MICE
39
Cooling MICE (RAL)
MICE 1 Hz 800 MeV 0.1 µA
ISIS 50 Hz 800 MeV 300 µA
40
Cooling 200 MHz cavity for MICE
Derun Li
41
Cooling Windows for the hydrogen absorbers for
MICE
42
COOLING etc. At FNAL there is a new MUCOOL Test
Area (MTA)
43
A.Bross
44
High pressure H2
Rolland Johnson, updated April 26, 2005
45
divide by 14 to get atm !
46
(No Transcript)
47
(No Transcript)
48
Frictional Cooling A. CaldwellMPI f.
Physik/Columbia University
Ionization stops, muon too slow
Nuclear scattering, excitation, charge exchange,
ionization

• Bring muons to a kinetic energy (T) where dE/dx
  increases with T
• Constant E-field applied to muons resulting in
  equilibrium energy
• Big issue how to maintain efficiency
• Similar idea first studied by Kottmann et al.,
  PSI

1/?2 from ionization
49
Acceleration

• Acceleration in previous schemes in the range
• of 88 MHz (CERN) to 200 MHz (RLAs).
• David Neuffer scheme of bunching, phase rotation,
  acceleration with 202 ? 330 MHz.
• High currents in short pulses need high power rf
  or large cavities (low frequencies) to store
  enough energy.

50
SCRF Cavity studies at Cornell
Fabrication at CERN
D. Hartill
Magnetron Nb film (1-2 mm) sputtering
51
Why Nb-Cu cavities?
52
Acceleration (FFAGs) POP (KEK) (protons 50 - 500
keV)
53
(No Transcript)
54

• Several scaling FFAGs exist or designed in Japan
• US/EU look at non-scaling FFAGs
• Smaller, simpler, cheaper?
• Non-scaling FFAGs have three unique features
• multi-resonance crossings
• huge momentum compaction
• asynchronous acceleration
• Proof-of-Principle electron machine planned
• Collaboration of 14 institutes EU, US, Canada,
  Japan
• Location Daresbury Laboratory, using ERLP
• Two correlated proposals submitted
• UK Basic Technology programme (hardware)
• EU FP6 opportunity to gain experience

After Edgecock
55
Electron Model at Daresbury
56
Reminder Goals(1) of WG3 Get more participation
and help (money people) for Targetry
Enhance comparison between solid and liquid
targets. Join the nTOF11 (high power target
experiment at CERN collaboration ! Cooling
(incl. rings etc.) Optimum for nufacts and
possibilities for muon colliders. Join MICE
! FFAGs and acceleration Find most economical
solution Join the e-model collaboration !
57
Reminder Goals (2) of WG3 Related to our focus
sessions Get more discussions going and get
(hopefully) more new ideas Proton driver
Define energy or define what needs still to be
explored to define it ! World wide design
study Get together to draft a plan and do the
follow-up
58
R B Palmer
Just keep going
59
Thank you