MICE: The International Muon Ionization Cooling Experiment Ulisse Bravar University of Oxford ICHEP...

MICE: The International Muon Ionization Cooling Experiment

Ulisse BravarUniversity of Oxford

ICHEP ‘04 1


Ulisse Bravar University of Oxford

18 August 2004 •Neutrino Factories•Ionization Cooling•The MICE experiment•MICE goals & structure •Present status of MICE•Future developments



ICHEP ‘04 2

Neutrino Beam Experiments

Neutrinos:• Three flavor states : = e, , • Three mass states : i i = 1, 2, 3

Mixing Matrix: 3 mixing angles • 12 -> solar • 13 -> reactor and beam • 23 -> atmospheric

Oscillation probability in vacuum: P(a->b) = sin2 2 sin2 (1.27 m2 L / E)

13 experiments:• present limit from CHOOZ • expected sensitivity from MINOS• Neutrino Factory with 40 kton large

magnetic detector

0.10 10 2.50 50 130



ICHEP ‘04 3

Neutrino Factory Layout• Target and collection

– High + and - yield– Sustain high power– Capture as many produced

pions as possible• Muon cooling

– Reduce +/- phase space to capture as many muons as possible in an accelerator

• Muon acceleration– Has to be fast, because

muons are short-lived !

From ECFA/CERN Study, 2004



ICHEP ‘04 4

Beam Emittance

Emittance:

x = x x’

• Liouville’s theorem use dissipative forces to reduce x

x

x’Large emittance

away from a focus

Large emittanceclose to a focus

Small emittance

B-field:x = constant

Cooling=

reduction of x

x’ = dx/dz = px/pz

z

x



ICHEP ‘04 5

Ionization Cooling

PRINCIPLE:

REALITY (simplified):

Stochastic cooling is too slow.A new method for and - is needed: ionization cooling

Cooling channel = LINAC + AbsorberAbsorber = cooling from dE/dx + heating from multiple scattering

Select absorber material with minimum multiple scattering for fixed dE/dx lossBest material is liquid hydrogen LH2 !!!

Absorber + RF + B-field



ICHEP ‘04 6

The MICE ExperimentGOALS:• Design, engineer and build a section of a cooling channel capable of giving

the desired performance for a Neutrino Factory.• Place this apparatus in a ~200 MeV/c muon beam and measure its

performance in a variety of operating modes and beam conditions.

CHALLENGES:• Contain cost. Neutrino Factory cooling channel is ~100 m long and cools the

beam by a factor 10. To be affordable, the MICE cooling channel is only ~6 m long and provides 10% to 15% measurable cooling.

• Measure emittance reduction OUT / IN to 10-3.• Operate high-gradient RF cavities in solenoidal field and with field

terminators.• Safely operate LH2 absorbers with very thin containers.

• Ionization cooling has never been demonstrated in the past. A working ionization cooling channel has never been built or tested !!!



ICHEP ‘04 7

The MICE CollaborationLouvain

DAPNIA

CEA/Saclay

Bari

Frascati

Genova

Legnaro

Milano

Napoli

Padova

Roma

Trieste

NIKHEF

Novosibirsk

CERN

Geneva

ETH

PSI

KEK

Tsukuba

Osaka

Brunel

Edinburgh

Glasgow

Liverpool

Imperial College

Oxford

CLRC RAL

Sheffield

Argonne

Brookhaven

Fairfield University

University of Chicago

Enrico Fermi Institute

Fermilab

Illinois Institute of Technology

Jefferson Lab

LBL

UCLA

NIU

Iowa

Mississippi

UC Riverside



ICHEP ‘04 8

MICE Layout

5.5 m



ICHEP ‘04 9

MICE PerformanceCOMPONENTS:

• 18 superconducting coils + cryocoolers. Solenoidal B-field, BZ ~ 4 T. Contain & focus the muons

in the channel.

• 3 liquid hydrogen LH2 absorbers in

thin Al containers. Provide dE/dx energy loss = cooling.

• 2 RF cavity modules, with a total of eight 201.25 MHz cavities. Field gradient = 8 MV/m. Restore lost energy.

• Upstream and downstream spectrometer. Measure beam emittance to 10-3.

• Particle ID detectors. Reject background events to 10-3.



ICHEP ‘04 10

MICE at RALSite Proposed for MICE Plant

Proposed route for services

Alternative route for services

Proposed site for controls & control room (presently the cable store and under the ISIS control room).

Proposed new linac cooling plant room

Hall has been emptied and preparation to host the experiment begun

Hole in the ISIS vault



ICHEP ‘04 11

MICE BeamlineDetailed design now beginning to achieve muon rates of the order of 100 Hz, as needed by MICE

z (m)

em

ittan

ce (

m r

ad)

Present beam almost ideal to demonstrate cooling

z (m)

COOLING IN MICE

Present design beam cools almost as well as ideal case

PSI solenoid

LH2

RF

out

in



ICHEP ‘04 12

Focus Coil-Absorber Module

Liqu

id h

ydro

gen

cell

35 c

m t

hick

Tw

o A

l win

dow

s on

ea

ch s

ide

of L

H2,

20

0 m

thi

ckne

ss

Superconducting coilsolenoidal B-field

Stored E = 1.3x106 JBpeak in coil = 6.27 T

Inter-coil F = 1.55x106 N

Cryostat

Side view

35 cm

Front view

30 cm



ICHEP ‘04 13

RF module(CERN, JLAB, LANL, LBL, RAL)

MICE R&DLH2 window

(ICAR, IIT, KEK, NIU, Oxford)

RF Cavity has been cleaned at J-Lab and

started nose

welding and ports annealing

at NASA in July 2004

The challenge:Thin Al windows ~ 120 m

+ safety regulationsFirst vessel has been filled with LH2 at FNAL in spring

2004



ICHEP ‘04 14

MICE TrackerAlternative option:

TPC with GEM readout (TPG)Baseline option:

Scintillating fiber tracker

5 planes of Sci-FiWith double layer.0.35 X0 per layer

The prototype



ICHEP ‘04 15

MICE Particle ID• Upstream:

– TOF hodoscopes with 10m path, 70 ps resolution

– Cherenkov / separation at better than

1% at 300 MeV/c • Downstream: 0.5% of s decay in flight:

need electron rejection at 10-3 to avoid bias on emittance reduction measurement– TOF hodoscope– Aerogel Cherenkov

(n=1.02, blind to s)– Calorimeter for MIP vs

E.M. Shower

Ckov Cal



ICHEP ‘04 16

- STEP I: spring 2006

STEP II: summer 2006

STEP III: winter 2007

STEP IV: spring 2007

STEP V: fall 2007

STEP VI: 2008

MICE Timescale2006

2007

2008

Subject to availability of funds…

……

……

……

……

……



ICHEP ‘04 17

Summary

• Ionization cooling is an essential ingredient in a neutrino factory

• MICE will demonstrate for the first time its feasibility

• Detailed design and simulation of MICE well under way

• Hardware elements are being built and tested

• Dedicated hall and beamline at RAL in preparation

• MICE should be up and running by 2008

MICE: The International Muon Ionization Cooling Experiment Ulisse Bravar University of Oxford ICHEP...

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