H. Haseroth

1
Neutrino Factory RD in Europe
or the art to talk for half an hour about nothing

• Helmut D. Haseroth
• CERN, Geneva, Switzerland

2

• Organisation of European RD
• Previously the CERN Neutrino Factory Working
  Group was quite active together with other
  European labs.

Then came (BIG surprise?) the LHC catastrophy
Huge reduction in accelerator RD
CLIC cut drastically (to around 4 MCHF)
SPL down to around 200 k
Neutrino Activity down to a bit of travel money
(Thats why I am still here)
3

• There are, however, a few positive points

We have some (positive) impact from directors of
big European labs with the intention to
contribute towards neutrino RD in spite of
CERNs reduction!
We have a European Muon Concertation and
Oversight Group (EMCOG)
FIRST SET OF BASIC GOALS The long-term goal is to
have a Conceptual Design Report for a European
Neutrino Factory Complex by the time of LHC
start-up, so that, by that date, this would be a
valid option for the future of CERN. An
earlier construction for the proton driver (SPL
accumulator compressor rings) is conceivable
and, of course, highly desirable. The SPL,
targetry and horn RD have therefore to be given
the highest priority.
4
EMCOG members
Pascal Debut
Rob Edgecock
5

• Charged me to create European working group
  called ENG (European Neutrino Group).
• Plenary meetings during Muon Weeks

Chair Helmut D. Haseroth Scientific
Secretary Rob Edgecock Sub-working groups with
conveners Proton Driver SPL Pascal
Debu, Roland Garoby Proton Rings Chris
Prior Targetry Roger Bennett
Collection Jean-Eric Campagne Frontend
Rob Edgecck Muon Acceleration Decay
Ring Francois Meot
One person still from CERN
6

• MUON Weeks

MUON Weeks Organized by V. Palladino
3/year at different locations in Europe at
participating labs. Covers physics and machine
aspects.
Resources at all European labs (manpower and
money) very limited gt ask the EU for support! No
hope in the past for support from EU neither for
high energy physics nor for accelerators,
especially not for CERN.
7

• but now there is FP6 (framework program 6) of
  the European Union

and ECFA is encouraged to ask for EU support.
Another committee of lab directors
have decided to form a European Steering Group on
Accelerator RD (ESGARD)
8
(No Transcript)
9
(No Transcript)
10
Neutrino Factories are part of ESGARD activities
11
 
From the minutes of the Restricted ECFA, November
29, 2002 The chairman thanked R.Aleksan and
ESGARD for the enormous amount of work they have
already done as well as M.Spiro who has set the
project going (Applause). RECFA fully supports
the steps taken by ESGARD in building up the bids
and will closely follow its work
Statement made in the Chairman's Summary of
Conclusions of the December 2002 SPC meeting at
CERN The SPC strongly supported the effort to
co-ordinate the accelerator RD at the European
level through the promotion of the ESGARD
initiative to get support of the European Union.
From the minutes of the Restricted ECFA, March
31, 2003 RECFA was impressed by the huge amount
of work done by ESGARD and congratulated them for
having so successfully built the proposal on
accelerator RD to the 6th EU Framework
Programme. This proposal includes 6 Joint
Research Projects and 3 Networks Activities,
which are all considered with high priority by
RECFA
12
Not a lot of money for these activities.
Typically 1 to 1.5 M for 5 years!
13
(No Transcript)
14
CERN Scheme
15
SPL basics
Study group since 1999 ? design of a
Superconducting Proton Linac (H-, 2.2 GeV). ?
higher brightness beams into the PS for LHC ?
intense beams (4 MW) for neutrino and
radioactive ion physics
CERN 2000-012
16
SPL design parameters
For neutrino physics, it has to be compressed
with an Accumulator and a Compressor ring
into 140 bunches, 3 ns long, forming a burst of
3.3 ms
17
A large inventory of LEP RF equipment is
available (SC cavities, cryostats, klystrons,
waveguides, circulators, etc.) which can
drastically reduce the cost of construction
LEP cavity modules in storage
Stored LEP klystrons
18
SPL lay-out

19
SPL cross section
20
Accumulator and Compressor Rings (PDAC)
2 synchrotron rings in the ex-ISR tunnel
21
Roadmap (1) 3 MeV injector

• 1) 3 MeV pre-injector 2006 at CERN
• On-going collaboration with CEA (Saclay-F) and
  CNRS (Orsay-F) to build, test and install at CERN
  a 3 MeV pre-injector based on the IPHI RFQ
  (Injecteur de Protons de Haute Intensité)

22
Roadmap (2) Linac4
Idea Take only the room temperature part of the
SPL (120 MeV) and install it in the PS South
Hall, to inject H- into the PS Booster ? gt
twice the number of protons/pulse in the PSB (5
1013)
120 MeV, 80m, 16 LEP klystrons
23
Linac4 layout in South Hall
to inflector PSB
24
HIPPI
In the frame of the CARE Initiative (ESGARD),
Joint Research Activity called HIPPI (High
Intensity Pulsed proton Injector) (total 6
JRAs) 8 European Laboratories join efforts for a
common RD on high intensity linacs with energy
in the range 3-200 MeV (CEA, CERN, ISN-Grenoble,
GSI, IAP-Frankfurt, FZ Juelich, RAL, INFN-Mi) to
prepare the upgrade of the proton accelerator
facilities at CERN, GSI, RAL 4 Work Packages 1.
Normal-conducting accelerating structures 2.
Superconducting accelerating structures 3.
Beam chopping 4. Beam dynamics Total
investment of some 15 M (including lab
salaries), request to EU for a contribution of 4
M over 5 years (2004-08)
For CERN, this means 130 k/yr ().
25
RD Topics - CCDTL
CCDTL Cell Coupled Drift Tube Linac, a simpler
and cheaper alternative to DTL for energy gt 40 MeV
CCDTL prototype
coupling cell
quadrupole
DTL-like accelerating cell (2 or 3 drift tubes)
26
Roadmap (3) SPL

• LEP RF cavities are getting older...
• New technology can provide better performance
  (gradient!)
• More EU-wide interest on 700 MHz frequency, bulk
  Nb
• Consequences
• Slowly relax the option on the LEP cavities
• Consider 700 MHz already for the 100-150 MeV at
  Linac4.
• Start market survey for 700 MHz klystrons
• RD options must be valid for both frequencies

27
Preliminary Layout of Neutrino Factory
28
European Scenarios

• SPL accumulator and compressor rings
• 5 GeV, 50 Hz synchrotron-based system
• 15 GeV, 25 Hz synchrotron-based system
• 30 GeV, 8 Hz slow cycling synchrotron
• 8 GeV, 16.67 Hz rapid cycling synchrotron for
  ISIS/Fermilab, plus upgrades

29
CERN PDAC Bunch Compression
30
RAL 5 GeV Proton Driver
31
ISIS MW Upgrades and possible use as a NF test bed

• 800 MeV,160 kW, 50 Hz, spallation neutron source
• Current upgrade to 240 kW with new ion source,
  RFQ and dual harmonic RF accelerating system

32
Stage 1 upgrade to 1MW neutrons

• Addition of a new synchrotron to increase beam
  energy to 3 GeV at 50 Hz
• Operated at 16.67 Hz, with every third ISIS
  pulse, could take beam to 8 GeV and be used as a
  test bed for 1 ns bunch compression

33
Stage 2 Upgrade to 4-5 MW

• Design and build new linac and two new booster
  synchrotrons with radius 39 m, operating at 50 Hz
  to 1.6 GeV (h3)
• Build a second 78 m racetrack
• Operate the two racetracks at 25Hz on alternate
  cycles
• 2MW beam power in each rings
• 4MW neutron source
• 2MW to neutron target
• 2MW to pion target
• 4MW to pion target

180 MeV Linac
39m radius
78m radius
34
Target Studies
35

• The Liquid Metal (Mercury) Jet
• The jet is constantly being reformed for every
  pulse. The jet becomes heated by the beam and
  disperses to hit the walls
• No Problems with
• Radiation Damage
• Shock Damage
• Power dissipation
• Possible Problems with
• Jet formation
• Interaction with the magnetic field
• Interaction of the mercury with other equipment
• Tests to date indicate that the jet is viable

36
Hg-jet p-converter target with a pion focusing
horn
37
Targetry
Many difficulties enormous power density ?
lifetime problems pion capture
Replace target between bunches Liquid mercury
jet or rotating solid target
Stationary target
Proposed rotating tantalum target ring
Densham
Sievers
38
Granular Target
39

• A Water Cooled Cu-Ni Rotating Band Target (BNL
  and FNAL, Bruce King)
• A Radiation Cooled Rotating Toroid, (RAL)
• TOROID OPERATES AT 2000-2500 K
• RADIATION COOLED
• ROTATES IN A VACUUM
• VACUUM CHAMBER WALLS WATER COOLED
• NO WINDOWS
• SHOCK? Pbar target OK. Tests using electron beam
  simulation indicate no problem.

40
V
No threading solenoid
V Lf R not fixed
Individual Targets Levitated
Reservoir for targets to collect and cool
41

• Advantages of Solid Target
• No windows
• Cooling in the walls
• Simple concept
• Disadvantages
• Large rotating toroid or individual targets
• Problems if toroid breaks
• Thermal shock - toroid breaks
• Very radioactive

42
Tests by RAL with electron beams show that
tantalum foils can withstand at least 200000
pulses and have lasted for 1000000.
43
Collector 1. Solenoid, 10-20 Tesla US
consider they have a long life (gt1 year)
design 2. Horn Problems with Heat
dissipation, Radiation damage, Stress
Possible 6 week life Studies will continue
44
Double horn concept
45
Horn prototype ready for tests
46
Acoustic frequency meas.
Horn eigenfrequencies from horn sound
dB
Hz
47
What we planned to do

• First inner horn 11 prototype
• Power supply for Test One 30 kA and 1 Hz,
  pulse 100 ms long
• First mechanical measurements
• Test of numerical results for vibration
• Test of cooling system
• Test Two 100 kA and 0.5 Hz, 100 ms long
• test of this power supply during last weeks
• Last test 300 kA and 50 Hz

Unknown schedule
Goal Horn Life-Time 6 weeks (2108 pulses)
48
(No Transcript)
49
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

50
If you do not like this
Try funneling! B. Autin, F. Meot, A. Verdier
51
What are the problems?

• Proton beam power 4 MW
• Target to cope with high power(must be a high Z
  target because of the modest proton energy)
• Horn to be pulsed at 50 Hz(Linac frequency)

• It would be much simpler if we had only 1 MW and
  e.g. 12.5 Hz

52
How does it work?
Why a funneling system?

• No exotic and expensive technology.
• Lifetime in excess of one year.
• Evolutionary design.

• The proton beam is switched to 4 targets in
  sequence.
• Each of the 4 pion lines contains an integrated
  system of target and magnetic horn.
• The funnel is made of large aperture magnets with
  quadrupolar and pulsed dipolar coils.

53
Funneling step by step
54
Horn Parameters
Radius of the waist mm 40
Voltage on the horn kV 4.2
Skin depth mm 1.25
Pulse length ms 93
Peak current kA 300
Repetition frequency Hz 50 ? 12.5
rms current in the horn kA 14.5 ? 3.6
Power dissipation by current kW 39 ? 9.7
55
Target dynamics

• High repetition frequency f reduces instantaneous
  energy deposited W at given power P W P/f .
• Long pulse heats the spheres adiabatically
  no shock.
• 
  
  Without funneling
• 
  With funneling

56
Polarities
Scheme 1 AC quadrupoles Scheme 2 DC
quadrupoles Good transmission. Reduced
transmission (2/3). Complicated power supplies
due Conventional power supplies. to high stored
magnetic energy.
57
Muon production

• Y Nm/Np versus longitudinal emittance for two
  transverse admittances
• et 1p cm (no cooling)
• et 4p cm (cooling)

58
Introduction
Frontend
59
CERN Baseline Frontend
Replaced with an all 88MHz frontend ? eliminates
44MHz cavities
Same performance as 44/88MHz channel
target and horn as before
15 m decay channel
cooling (6.4 m/cell)
7.2 m phase rotation
60
Frontends without Cooling
Grahame Rees et al
Pion-muon decay channel
88 MHz muon linac
61
Frontends without Cooling
Transmission comparable to 44/88MHz scheme
62
AG Phase Rotation
Jaroslaw Pasternak et al

• Extend AG structure to phase rotation - 8
  triplet FODO cells matched to decay channel
• Add magnetic compression chicane - 2
  periods, each 3 FODO cells

1.8x increase
63
Rings
Grahame Rees et al
S solenoid, A absorber, 36 cavities in blocks
of 3

• Hybrid ring, using solenoids and dipoles
• 44m circumference 18m straights, 4m bends
• 4m sections for injection and extraction
• Initial results looking promising

64
Working Group of F. Meot / CEA - DAPNIA
65
Working Group of F. Meot / CEA - DAPNIA
Design studies - Plans for the future   a full
design of a single- or double-RLA, a full design
of an FFAG ring - 6D tracking, DA, etc. polytron
scheme ? converge on, finalise muSR design in all
cases, perform tracking simulations end to
end need develop simulation (including tracking)
tools "These acceleration systems are the largest
cost items in the system" DN, Acceleration for
the mu-storage ring neutrino-source prime goal
reduce costs
66
Muon Colliders
Some time ago regarded by some people as science
fiction, it must be noted that the advances in
cooling theory and technology are so impressive
as to consider this type of machine as a real
possibility in the future.
High Energy Frontier
67
Possible step 0 Neutrino SUPERBEAM
300 MeV n m Neutrinos small contamination from
ne (no K at 2 GeV!)
Fréjus underground lab.
A large underground water Cerenkov (400 kton)
UNO/HyperK is best choice also proton decay
search, supernovae events solar and atmospheric
neutrinos.
68
Design studies (preliminary thoughts)
NUFACT (superbeam/neutrino factory)
collection, horn
4 MW target station
proton driver
muon acceleration and storage
proton/H- driver nuclear-synergy group
Cooling
NA BENE
Large cavern and UNO
EURISOL
betabeam acceleration to g 70 (CERN)
Driver
isol production of rare ions
Mass separator
Post-accelerator
5 MW target
Scientific instrumentation
69
Many thanks to my European colleagues for their
help to prepare this talk, in particular to R.
Aleksan R. Garoby Ch. Prior R. Bennett S.
Gilardoni B. Autin R. Edgecock F. Méot M.
Lindroos and many others