Ken Peach

Particle Physics Department

Neutrino Factory Overview

Ken Peach

A neutrino factory is …

… a medium energy [10 GeV 50 GeV]

… high Intensity [>1020 muon decays/year]

… muon storage ring [racetrack, triangle, bow-tie]

… with long straight section(s)

… pointing to detector(s) several thousand km distant

… designed to measure the CP/T-violating phase in the MNS designed to measure the CP/T-violating phase in the MNS matrixmatrix with good precisionwith good precision

Ken Peach

Muon

Storage

Ring

A neutrino factory is …

… an accelerator complex designed to produce >1020 muon decays per year directed at a detector thousands of km away

Principal Components

High Power H- sourceProton

DriverTarget Capture

Co

olin

g

Muon Acceleration

‘near’ detector (1000-3000km)

‘far’ detector (5000-8000km)

‘local’ detector

Ken Peach

Why?

• Neutrino physics has become a very hot topic– Fundamental particle– Recent observations show that neutrinos are not massless– Neutrino masses are “something new”

• Physics “beyond the standard model”

– Implications for cosmology

– Possible (part of the) explanation for the matter/antimatter asymmetry of the Universe

• Why is there a physical universe at all?

Ken Peach

The Neutrino Factory

CPV: > 1020 muon decaysConventional beams

& K decaySome flavour selectivityContaminationFluxes ~1017-1018

Reactor beamsPure e

Huge FluxesVery low energy (MeV)

Super Conventional beams(& some decay

Flavour selectivity ()Low Contamination at E<200MeVFluxes ~1018-1019

The Neutrino Factory

Ken Peach

2/

2/

1212

1212

1313

1313

2323

2323

1

1

1

1

i

i

i

i

MNS

e

e

cs

sc

ces

esc

cs

sc

U

Neutrino Mixing

Parameters of neutrino oscillation

1 absolute mass scale

2 squared mass differences

3 mixing angles

1 phase

2 Majorana phases βα,

)esinθ always ( δ

θθθ

ΔmΔm

m

iδ13

132312

232

221

νe

, ,

,

221

232

231

2i

2j

2ji

ΔmΔmΔm

mmΔm

21

31

61

21

31

61

31

32 13.0

25-221

2-3232

eV10 0.8)(7.3

eV10 0.4)(2.6

m

m

Ken Peach

Neutrino matter-antimatter asymmetry

L/E

sinsinsin

2sin2sin2sincos

42

2

1223131321

232

221

ELm

ELm

eCPoddP

Ken Peach

Matter v. CP-violation effects

Ken Peach

A neutrino factory provides …

flavour tagged background free normalised (calibrated flux)equal fluxbeams of

muon antineutrinos and electron neutrinos from + muon neutrinos and electron antineutrinos from -

In principle, gives a complete set of measurements

e, x disappearance

e appearance

e, appearanceand

charge conjugate

Ken Peach

Shape of Muon Storage Ring

• Racetrack– Single far detector, relatively simple construction

• Maximum ‘efficiency’ ~ 40%• Very intense local beam for conventional neutrino experiments

• Triangle– Two detectors at different distances

• (~1000km, ~3000km or ~3000km, ~6000km)• Maximum ‘efficiency’ ~80%

– Ring built in a steeply inclined plane– Steeply rising local beam for conventional neutrino experiments

• Bow-tie– Advantages as for triangle

• Because of the ‘bow-tie’, the depth is ~½ triangle depth– 2 Steeply rising local beams for conventional neutrino

experiments– May ruin the precision knowledge of the neutrino spectrum

Ken Peach

Where could a neutrino factory be built?

FNALBNL

CERNGSICEAINFN

JHF

DUBNA

RAL?

Ken Peach

Possible Baselines

Gruber

Ken Peach

Proton or H- Source and Proton Driver

• Pion production in the 200 - 400 MeV region is essentially proportional to the beam power over a wide range of proton energies– 1-5 MW beam power required for 1020 1021 muons per year– mA proton currents required

• Proton energy is a critical design choice– Ideas at 2.2 GeV (CERN), 5 GeV (RAL), 8 & 16 GeV (FNAL),

15 GeV (CERN), 24 GeV (BNL), 50 GeV (JHF)– ‘figure of merit’ is probably

• pions per steradian per proton per GeV

– Part of the overall design optimisation

• Need better data on pion production– HARP, E910

Ken Peach

Example: Proton Driver Design

Similar features needed for

• ESS

• Radioactive Ion Beams

• Accelerator Transmutation of Nuclear Waste

• IFMIF

H

Ion Source

LEBT 280 MHz RFQ Chopper 280 MHz DTL

2.493 MeV75 keV 180.2 MeV

Section

Prior & Rees

Ken Peach

The proton power of a neutrino factor

Ken Peach

Pion Source & Decay Channel

Solenoid option – alternative magnetic horn

Ken Peach

Target issues/muon source

• Liquid jet … or … solid (moving?) target– no clear consensus

• much R&D needed

– Existing/future high power targets

• RAL/ISIS• CERN/ISOLDE• CERN &

FNAL/antiproton• SNS/Oak Ridge• FNAL/NuMI• PSI,TRIUMF &

KEK/muon sources

– clear area for R&D• material• radiation & heating

Mohkov (FNAL)

>1 Tera Rad !

Ken Peach

Target Studies for a Future Neutrino Factory

Temperature jump (cut-away section of target material)

Shock wave stress intensity contours 4 µs after 100 kJ, 1 ns proton pulse

Pion production target for a future neutrino factory: Pulsed proton beam induced shock waves in section of solid tantalum target

Shock wave stresses

Proposed rotating tantalum target ring

Roger Bennett, Chris Densham & Paul Drumm

Ken Peach

PULSED EFFECTS

Proton beam pulse length (~1 ns) at 100 Hz rate.

rotation

individual overlapping beam pulses on the target, 20 cm long

Faster rotation, illumination by each pulse separate until at v = 20 m/s they just touch.

Slow target rotation - areas illuminated by pulses overlap

At speeds greater than 20 m/s the areas of each pulse separate

The maximum power at a pulse repetition rate f is:

W = 0.322·f

W = 32 MW at 100 Hz

Roger Bennett, Chris Densham & Paul Drumm

Ken Peach

POWER DISSIPATION

0.01 0.1 1 10 100 1 103

0.01

0.1

1

10

100

1 103

power

MW

10 m

10 m

v = 100 m/s

1 m

1 m

100 m

100 m

0.1 m

200 m

20 m10 m

2 m

0.1 m

1 m

2000 m

1000 m

radius/velocity

v = 20 m/s

v = 10 m/s

v = 1 m/s

v = 0.1 m/s

1000 m

10 m

100 m

10000 m

Roger Bennett, Chris Densham & Paul Drumm

Ken Peach

Cooling

• Cooling will (probably) work

… but experiments needed pions longitudinal phase space at production. (fluka calculation, 26 mm mercury target, 2.2 GeV beam)

Lombardi

Ken Peach

One Challenge: Ionization Cooling

PT

PL

After ionisation energy loss

After Multiple Scattering

After Acceleration

Muon Momentum

Ken Peach

Heating and Cooling

Zisman

Ionization loss Multiple scattering

Ken Peach

Muon Ionisation Cooling Experiment

Ken Peach

ISIS as MICE host

HEP Test Beam Hall

Potential MICE

location

An international study of muon beam options

(including CERN, FNAL, TRIUMF, PSI) ISIS was

identified as the best technical location for the

MICE test facility

Ken Peach

Ionisation loss

Zisman

Ken Peach

Muon Ionisation Cooling Experiment

What does it have to do?

• Demonstrate a cooling channel is feasible

• Measure a 10% reduction in emittance

• Investigate channel performance as a function of

Emittance: 1πmm.mrad to 50 πmm.mrad

Energy: 100 to 400 MeV

Energy spread: “zero” to 20%

Phase, B-field, etc?

• Use a single particle beam

Ken Peach

- STEP I:

2004

STEP II: summer 2005

STEP III: winter 2006

STEP IV: spring 2006

STEP V: fall 2006

STEP VI: 2007

Blondel

Ken Peach

Pion-muon decay channel

88 MHz muon linac

Reverse Rotation Lattice

Chris Prior, Graham Rees

An alternative to cooling?

Ken Peach

Muon Acceleration

• 2 or 3 stages– Linac (to 1 2 GeV?)– Recirculating linac 1 (to 10 GeV?)– Recirculating linac 1 (to final energy)

• Some possible parameters (CERN)

Haseroth

Ken Peach

Muon Storage Ring

• A design (CERN)

Haseroth

Ken Peach

Cost breakdown - subsystemsF

NA

L F

easi

bil

ity

stu

dy

Ken Peach

Where could a neutrino factory be built?

FNALBNL

CERNGSICEAINFN

JHF

DUBNA

RAL?

Ken Peach

Neutrino Factory

Neutrino Factory Footprint

Ken Peach

Encouragement

Research Fortnight, 15th January 2003

“Hosting a global facility like the neutrino factory would bring substantial scientific

and commercial benefits to the UK”

“We believe that an ambitious and far sighted approach is needed to secure

maximum benefit for UK science”

‘the government will need to show “greater willingness” … to carry out the necessary

development work to put together a serious bid, and then commit the

necessary resources … to see it through’

House of Commons Science and Technology Select Committee.

First Report on the work of PPARC,

17th December 2002

Ken Peach

A neutrino factory …

… is needed (probably) to measure CP violation in the lepton sector

… is (probably) feasible

… but significant challenges

Design – muon energy, baseline optimisationMachine – target, cooling, r/f (muon acceleration)Detector – flavour identification with charge measurement

… and COST