neutrino factory r&d in europe

H. HaserothJune 5, 2003 NuFact03

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Neutrino Factory R&D in Europe

Helmut D. HaserothCERN, Geneva, Switzerland

or the art to talk for half an hour about nothing…


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Organisation of European R&D:

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 R&D

CLIC cut drastically (to around 4 MCHF)SPL down to around 200 k€

Neutrino Activity down to a bit of travel money

(That‘s why I am still here…)


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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 R&D in

spite of CERN‘s reduction!

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 R&D have therefore to be given the highest priority.

We have a European Muon Concertation and Oversight Group (EMCOG)


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Rob Edgecock

Pascal Debut

EMCOG members


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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…


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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 => 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.


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…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

of CCLRC, CERN, DAPNIA/CEA, DESY, LNF, Orsay/IN2P3, and PSI in consultation with ECFA

have decided to form a European Steering Group on Accelerator R&D

(ESGARD)


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Two Contact Groups (CG) issued from ESGARD have been set up to bidding preparation, one of electron-positron linear colliders and one on super proton accelerators and neutrino beams. These CGs will create Working Groups (WG) with the people of the community involved in the relevant activities. They also maintain close contact with existing committees, boards and teams. The mandate of the CGs is to:

1.To act as liaison between ESGARD and the community involved in accelerator studies related to the selected theme. 2.To inform the relevant community of the proposals being developed on accelerator R&D for FP6 and form a Working Group to :

•Establish a proposal for Networking Activities (NA) related to each theme, •Develop proposals for Joint Research Projects (JRP), •Explore whether Transnational Access (TA) as defined by the EU commission is applicable to the accelerator community and, if so, make a proposal,

3.Together with the WG and in consultation with ESGARD, propose the names of the coordinators for the different activities (NA, TA and JRP). 4.Investigate with the WG whether proposals for Design Studies (DS) and/or Construction of New Infrastructures (CNI) as defined by the EU commission is applicable and identify their scope.

•Contact Group 1 on e+e- Linear Colliders : A. Antonelli, G. Guignard, F. Richard, S. Smith and D. Trines

•Contact Group 2 on super proton-accelerators and neutrino beams : R. Aleksan, H. Haseroth, P. Norton and A. Wrulich


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The R&D on accelerators for high energy physics is organised around three main future world-wide projects:

1.Electron-positron linear colliders with energies ranging between 500 and 3000 GeV in the centre-of-mass system, using the technology of superconductive high gradient accelerator structures recently developed by the TESLA international collaboration, and aiming at exploiting as well the two-beam technique for obtaining ultra-high gradients at room temperature developed by the CLIC international collaboration. 2.Facilities providing intense neutrino beams (see for example NUFACT, using both improvements to the existing methods based on intense proton beams, and the more novel techniques based on radioactive ion or muon beams.3.Facilities providing proton beams with ultra-high intensities and energies, aiming at very large hadron colliders, and covering as well luminosity and energy upgrades of the LHC at CERN.

Neutrino Factories are part of ESGARD activities


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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 R&D 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 R&D 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


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Vittorio Palladino

Not a lot of money for these activities. Typically 1 to 1.5 M€ for 5 years!


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A possible proton driver for a Neutrino Factory


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CERN Scheme


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SPL basicsStudy 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

H- RFQ RFQ1 chop. RFQ2DTL CCDTL RFQ1 chop. RFQ2 0.52 0.7 0.8 dump

Source Low Energy section DTL Superconducting section

95 keV 3 MeV 7 MeV 120 MeV 2.2 GeV

40MeV 237MeV6 m 64 m 584m

PS / Isolde

Stretching andcollimation line

Accumulator Ring

383MeV

chopping

4 m

660 m

CERN 2000-012


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SPL design parameters

H- RFQ RFQ1 chop. RFQ2 RFQ1 chop. RFQ2 0.52 0.7 0.8 dump

Source Low Energy section DTL Superconducting section

45 keV 3 MeV 120 MeV 2.2 GeV

40MeV 237MeV

6 m 64 m 584 m

PS / Isolde

Stretching andcollimation line

Accumulator Ring

Debunching

383MeV

668 m

DTL CCDTLchopping

For neutrino physics, it has to be compressed with an

Accumulator and aCompressor ring into

140 bunches, 3 ns long,forming a burst of 3.3 s

Ion species H-Kinetic energy 2.2 GeVMean current during the pulse 13 mADuty cycle 14.0 %Mean beam power 4 MWPulse frequency 50 HzPulse duration 2.80 msDuty cycle during the beam pulse 61.6 %Maximum bunch current 22.7 mABunch length (total) 0.5 nsEnergy spread (total) 0.5 MeVNormalised rms horizontal emittance 0.4 mm mradNormalised rms vertical emittance 0.4 mm mradLongitudinal rms emittance (352 MHz) 0.3 deg MeV


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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


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SPL lay-out


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SPL cross section


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Accumulator and Compressor Rings (“PDAC”)

T= 2.2 GeVIDC = 13 mA (during the pulse)IBunch= 22 mA3.85 108 protons/bunchlb(total) = 44 ps*H,V=0.6 m r.m.s

(140 + 6 empty)per turn

845 turns( 5 140 845 bunches per pulse)

no beam

2.8 ms20 ms

140 bunches

20 ms

3.2 s

Charge exchangeinjection

845 turns

PROTON ACCUMULATORTREV = 3.316 s

(1168 periods @ 352.2 MHz)

1 ns rms(on target)

22.7 ns

TARGET

H+140 bunches1.62 1012 protons/bunchlb(rms) = 1 ns (on target)

Fast ejection

KICKER20 ms

3.3 slb(total) = 0.5 ns

DRIFT SPACE+

DEBUNCHER

H-

11.4 ns

22.7 ns

5bunches

Fast injection(1 turn)

BUNCH COMPRESSORTREV = 3.316 s

(1168 periods @ 352.2 MHz)

BUNCHROTATIONRF (h=146)

Fast ejection

RF (h=146)

3 emptybuckets

17.2 ms

2 synchrotron ringsin the ex-ISR tunnel


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Roadmap (1): 3 MeV injector1) 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)

E C R S IL H I sou rcean d L E B T

R F Q H E B T w ithB e a m D ia g n o st ic s

sp ectrom eter

B e a mStopp er

B ea m P o w er : 3 0 0 k W

9 5 K e V

2 R F S y ste m s3 5 2 M H z - 1 .3 M W

3 M e V

1 0 0 K VH V p latfo rm

8,6 m 6 m 14 m


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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 > twice the number of protons/pulse in the PSB

(5 1013)

H- RFQ RFQ1 chop. RFQ2DTL CCDTL

95 keV 3 MeV 120 MeV 150 MeV

40MeV 6 m 64 m

chopping

4 m

SCL/SC

120 MeV, 80m, 16 LEP klystrons


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Linac4 layout in South Hall

"NEW LINAC" Layout in the PS South Hall - version 5.2.2002

12.0

m

PS Access

RF Workshop

Loading Area

Storage AreaRFQ Test stand352 MHz Test StandLoading

Area

to inflector & PSB


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HIPPIIn the frame of the CARE Initiative (ESGARD), Joint Research Activity

called HIPPI (High Intensity Pulsed proton Injector) (total 6 JRA’s)8 European Laboratories join efforts for a common R&D 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 structures2. Superconducting accelerating structures3. Beam chopping4. 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 (…).


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R&D Topics - CCDTL

CCDTL = Cell Coupled Drift Tube Linac, a simpler and cheaper alternative to DTL for energy > 40 MeV

quadrupole coupling cell

DTL-like accelerating cell(2 or 3 drift tubes)

CCDTL prototype


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• LEP RF cavities are getting older... • New technology can provide better performance (=gradient!)• More EU-wide interest on 700 MHz frequency, bulk Nb• Consequences:

1. Slowly relax the option on the LEP cavities2. Consider 700 MHz already for the 100-150 MeV at

Linac4.3. Start market survey for 700 MHz klystrons4. R&D options must be valid for both frequencies

Roadmap (3): SPL …


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Preliminary Layout of Neutrino Factory


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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


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CERN PDAC: Bunch Compression


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180 MeV H- Linac

Two 1.2 GeV, 50 Hz Rapid Cycling Synchrotrons

2 bunches of 2.5 1013 protons

4 bunches of 2.5 1013 protons

Two 5 GeV, 25 Hz Rapid Cycling Synchrotrons

Collimation

Injection

Momentum Ramping

RAL 5 GeV Proton Driver


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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


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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


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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 (h=3)

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

78m radius

39m radius

180 MeV Linac


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Current StatusCERN have had considerable success with studies of mercury jets (with BNL), including within solenoidal fields.

CERN are are also studying granular targets.

PSI are building a liquid metal target. They are involved with the US in liquid metal targets for high power spallation sources.

RAL has done preliminary tests on shock waves in hot tantalum using electron beams.

CERN ISOLDE have experience of the problems of radioactivity and of shock waves. They have a laboratory suitable for handling active materials and molten metals - mercury.

CERN, PSI (not pulsed) and RAL have facilities providing high power proton beams. Also in the US at Los Alamos, Brookhaven and FNAL.

Target Studies


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The Liquid Metal (Mercury) JetThe 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


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Hg-jet p-converter target with a pion focusing horn


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Proposed rotating tantalum target ring

Targetry

Many difficulties: enormous power density lifetime problems pion capture

Replace target between bunches:Liquid mercury jet or rotating

solid target

Stationary target:

Densham Sievers


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Granular Target


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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.


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Individual Targets

Levitated

V

Reservoir for targets to collect

and cool

V = Lf

R not fixed

No threading solenoid


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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


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Tests by RAL with electron beams show that tantalum foils can withstand at least 200000 pulses and have lasted for 1000000.


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Collector

1. Solenoid, 10-20 Tesla

US consider they have a long life (>1 year) design

2. Horn Problems with: Heat dissipation, Radiation damage, Stress Possible 6 week life Studies will continue


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Double horn concept

B field

0.001

0.01

0.1

1

1 100Radius (mm)

B (a

.u.) I = 300 kA

I = 600 kASum


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Horn prototype ready for tests


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Acoustic frequency meas.Horn eigenfrequencies from horn “sound”

Hz

dB


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What we planned to do• First “inner” horn 1:1 prototype • Power supply for Test One:

30 kA and 1 Hz, pulse 100 s longFirst mechanical measurements Test of numerical results for vibration Test of cooling system

• Test Two: 100 kA and 0.5 Hz, 100 s long– test of this power supply during last weeks

• Last test: 300 kA and 50 Hz Unknown

schedule

Goal: Horn Life-Time 6 weeks (2*108 pulses)


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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 target30° C- Exit from target 100° C

• Total Hg inventory 10 t• Pump power 50 kW


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If you do not like this…

Try funneling!B. Autin, F. Meot, A.

Verdier


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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


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How does it work?• 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.

•No exotic and expensive technology.

•Lifetime in excess of one year.

•Evolutionary design.

Why a funneling system?


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Funneling step by step


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Horn ParametersRadius of the waist [mm] 40Voltage on the horn [kV] 4.2

Skin depth [mm] 1.25 Pulse length [s] 93Peak current [kA] 300Repetition frequency [Hz] 50 → 12.5rms current in the horn [kA] 14.5 → 3.6Power dissipation by current [kW] 39 → 9.7


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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

0.2 0.4 0.6 0.8 1ts50

100

150

200

250

TK


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PolaritiesScheme 1: AC quadrupoles Scheme 2: DC quadrupolesGood transmission. Reduced transmission (2/3).Complicated power supplies due Conventional power supplies.to high stored magnetic energy.

Q

H

V1 2 3 4 5

Q

H

V1 2 3 4 5


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Muon production• Y = N/Nversus longitudinal emittance for two transverse admittances:

t = 1 cm (no cooling) t = 4 cm (cooling)

0.5 1 1.5 2l eV.s

5

10

15

20

Y%

t cm 1

t cm 4

High field AG line

Conventional AG line

Solenoid


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IntroductionIntroduction

FrontendFrontend


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CERN Baseline FrontendCERN Baseline FrontendReplaced with an all 88MHz frontend Replaced with an all 88MHz frontend eliminates 44MHz eliminates 44MHz

cavities cavities

target

and ho

rn:

as

before

15 m deca

y channel

7.2 m phase

rotat

ion

cooling (6

.4 m/ce

ll)

80 MHz

Decay Rotation Cooling I Acceleration I

Acceleration II

Length [m] 15 8 90 10 450

Diameter [cm] 40 40 40 30 20

B-field [T] 4 4 4 4 quads

Frequency [MHz] 80 80 80 80-200

Gradient [MV/m] 4 4 4 4-10

Kin Energy [MeV] 200 200 300 2000

Same performance Same performance as 44/88MHz as 44/88MHz

channelchannel


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Frontends without CoolingFrontends without CoolingGrahame Rees et alGrahame Rees et al

Muon Front Ends Decay Region .2 GeV

44 MHz Rotation .2 GeV

44 MHz Cooling .2 GeV

44 MHz Accel’n .28 GeV

88 MHz Cooling & Acceleration .4 GeV 286.0 m

Decay Region .19 GeV

88 MHz Rotation .19 GeV

88 Mhz Acceleration .4 GeV 132.7 m

Decay Region .19 GeV

Reverse Rotation .19 GeV

88 MHz Acceleration .4 GeV 128.0 m

Pion-muon decay channel

88 MHz muon linac


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Frontends without CoolingFrontends without Cooling

Solenoid

channel

Es=190MeV

RF phase

rotation

channel

Es=190MeV

Linac

Es=400MeV

(Transmission

=77%)

Solenoid

channel

Es=190MeV

Inverse

rotation

channel

Es=190MeV

Linac

Es=400MeV

Transmission comparable to 44/88MHz scheme


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AG Phase RotationAG Phase Rotation

Jaroslaw Pasternak et alJaroslaw Pasternak et al

• Extend AG structure to phase rotation:Extend AG structure to phase rotation: - 8 - 8 triplet FODO cells matched to decay channeltriplet FODO cells matched to decay channel• Add magnetic compression chicane:Add magnetic compression chicane:

- 2 periods, each 3 FODO cells- 2 periods, each 3 FODO cells

1.8x increase1.8x increase


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RingsRings

S = solenoid, A = absorber, 36 cavities in blocks of 3

Grahame Rees et alGrahame Rees et al

• Hybrid ring, using solenoids and dipolesHybrid ring, using solenoids and dipoles• 44m circumference: 18m straights, 4m bends44m circumference: 18m straights, 4m bends• 4m sections for injection and extraction4m sections for injection and extraction• Initial results looking promisingInitial results looking promising


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Working Group of F. Meot / CEA - DAPNIA


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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 designin all cases, perform tracking simulations end to endneed 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


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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.

Muon Colliders

High Energy Frontier…


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300 MeV Neutrinos

small contamination from e (no K at 2 GeV!)

A large underground water Cerenkov (400 kton) UNO/HyperK is best choicealso : proton decay search, supernovae events solar and atmospheric neutrinos.

Possible step 0: Neutrino SUPERBEAM

Fréjus underground lab.


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EURISOL

NUFACT (superbeam/neutrino factory)

isol production of rare ions

+betabeam acceleration to (CERN)

4 MW target station collection, horn

Cooling muon acceleration and

storage + proton/H- driver nuclear-synergy group

NA : BENE

Large cavern and UNO

proton driver

Design studies (preliminary thoughts)

Driver

Post-accelerator

Mass separator

5 MW target Scientific instrumentation


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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…

neutrino factory r&d in europe

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