The R&D effort towards a neutrino factory

M. BonesiniSezione INFN Milano Bicocca

Dipartimento di Fisica G. Occhialini

Ro

adm

ap

2030

2010

2005

2015-20

K2K-II

JHF

? Off-Axis

HARP

MICE/MERIT

? Factory

CNGSNuMI

disappearance

down to 1o

appearanceNC/CC

CP violation

F R

&D

MiniBooNE

LSND?

KamLand

m212,12 at 2%

Yellow ReportCERN-2004-002, ECFA/04/230Further informations:http://muonstoragerings.cern.ch

ISS

NOW 2006 - Otranto

beams: conventional and nufact beams

Problem in conventional beams: a lot of minority components (beam understanding)

Following muon collider studies, accelerated muons are ALSO an intense source of “high energy”

Crucial features high intensity (x 100 conventional

beams) known beam composition

(50% 50% e )

Possibility to have an intense e beam

Essential detector capabilities:

detect and determine their sign

WANF

(conventional)

Nufact

ee ee

IEEE 2004 - Roma

+ e++ +e

+

Oscillate

Wrong Sign muons

1016p/s

3 1020 eyr

3 1020 yr

0.9 1021 yr

IEEE 2004 - Roma

Sensitivity of Nufact

present limit from the CHOOZ experiment0.75 MW JHF to super Kamiokande with an off-axis narrow-band beam, Superbeam: 4 MW CERN-SPL to a 400 kt water Cerenkov@ Fréjus (J-PARC phase II similar)Neutrino Factory with 40 kton large magnetic detector.

0.10 10 2.50 50 130

M. Mezzetto

X 5

NOW 2006 - Otranto

Towards a Neutrino Factory: the challenges

• Target and collection (HARP/MERIT)

– Maximize + and - production

– Sustain high power (MW driver)

– Optimize pion captureINTENSE PROTON SOURCE (MW);

GOOD COLLECTION SCHEME

• Muon cooling (MICE)

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

• Muon acceleration

– Has to be fast, because muons are short-lived !

(RLA, FFAG, … not covered in this talk)

IEEE 2004 - Roma

Neutrino Factory studies and R&D

USA, Europe, Japan have each their scheme. Only one has been costed, US study II:

Neutrino Factory CAN be done…..but it is too expensive as is. Aim: ascertain challenges can be met + cut cost in half.

+ detector: MINOS * 10 = about 300 M€ or M$

US Study II

IEEE 2004 - Roma

Study to optimize target : HARP experiment at CERN

~420 Mtriggers collected on different targets 1.5-15 GeV/c4 detector (TPC+forward)First results for NUFACT target optimization (see G. Catanesi talk)

HARP at CERN PS

A Layout of the Harp experiment

Tpc

spectrometer

CerenkovTof

Target length ()

BeamMomentum (GeV)

#events(millions)

2 (2001)

5

100

±3± 5± 8

± 12± 15

Negative only 2% and 5%

233.16

C

Al

Cu

Sn

Ta

Pb

K2K Al5, 50, 100,

replica

+12.9 15.27

MiniBooNE Be +8.9 22.56

Cu “button”Cu +12.9, +15

1.71

Cu “skew”Cu 2 +12

1.69

Cryogenictargets

N7

6 cm

±3± 5± 8

± 12± 15

58.4308

D1

H1

DeuteriumH2 18 cm ±3, ±8,

±14.513.83

WaterH20 10, 100 +1.5,

+8(10%)9.6

First results for NUFACT targetry optimizatio

From S. Borghi talk at NUFACT06

• Proof of principle demonstration of Hg-jet target for a 4MW proton beam, contained in a 15-T solenoid for maximal collection of soft secondary pions

– 24 GeV proton beam from CERN PS• Start Spring 2007 (nTOF area)

15-T solenoid during tests at MIT

Hg delivery and containment system under construction at ORNL. Integration tests scheduled this Fall at MIT.

MERIT (MERcury Intense Target)

IEEE 2004 - Roma

The big problem: reduction of emittance

The muon beam emittance must be reduced for injection into the acceleration system• Energy spread ► phase rotation• Transverse emittance ► cooling

AcceleratoAccelerator acceptance

R 10 cm, x’ 0.05 rad rescaled @ 200 MeV

and after focalization

NOW 2006 - Otranto

Muon ionization cooling

principle reality (simplified)

reduce pt and pl

increase pl

heating

Stochastic cooling is too slow.

A novel method for + and - is needed: ionization cooling

A delicate technology and integration problem Need to build a realistic prototype and verify that it works (i.e. cools a beam)Difficulty: affordable prototype of cooling

section only cools beam by 10%, while standard emittance measurements barely achieve this precision.

Solution: measure the beam particle-by-particle

IEEE 2004 - Roma

Muon Ionization Cooling Experiment Build a section of cooling channel long

enough to provide measurable cooling (10% ) and short enough to be affordable and flexible

Wish to measure this change to 1% Requires measurement of emittance of

beams into and out of cooling channel to 0.1% !

Cannot be done with conventional beam monitoring device

Instead perform a single particle experiment: High precision measurement of

each track (x,y,z,px,py,pz,t,E) Build up a virtual bunch offline Analyse effect of cooling channel

on many different bunches Study cooling channels parameters

over a range of initial beam momenta and emittances

• Experiment approved in 2003 y CLRC and scheduled for first run in October 2007

MICE setup: cooling + diagnostics

NOW 2006 - Otranto

RF cavitiesRestore lost pL

•8 MV/m accelerator gradient•4 T axial magnetic field

MICE cooling channel R&D

LH2 absorbersreduce muons momenta•Large ionization energy loss rate•Low scattering

First cavity has been assembled

Be window to minimize thickness

The challenge:Thin windows + safety regulations

NOW 2006 - Otranto

MICE cooling channel

•

• High gradient reacceleration– 10% reduction of muon emittance for 200 MeV muons requires ~20MV RF

• Challenge: integration of these elements in the most compact and economic way

• 3 Liquid Hydrogen absorbers

• 8 cavities 201MHz RFs, 8MV/m

• 5T SC solenoids

0

2

32 2

)014.0(11

XmEEds

dE

ds

d nn

Minimize heating term:•Absorber with large X0

•SC solenoid focusing for small T

NOW 2006 - Otranto

equilibrium emittance = 2.5 mm.radian

cooling effect at nominal inputemittance ~10%

curves for 23 MV, 3 full absorbers, particles on crest

Acceptance: beam of 5cm and 120 mrad rms

Quantities to be measured in a cooling exp

Difficulty: standard emittance measurement barely reach the required 0.1 % precision

Solution: Single particle measurement

•The advantages:–Separate measurement of transmittance and emittance variation

–A precision on (Tin-T

out) <10-3 can be achieved

•The challenge: The measurement should not affect the cooling

Muon Emittance measurement

Determines, for an ensemble (sample) of N particles, the moments:Averages <x> <y> etc… Second moments: variance(x) x

2 = < x2 - <x>2 > etc… covariance(x) xy = < x.y - <x><y> >

Covariance matrix M = M =

2't

't'y2

'y

't'x2

'x

'tt2t

'yt2y

'xt'xy'xxxtxy2x

...............

............

............

............

............

2'y'xyx

D4

't'y'xytxD6

)Mdet(

)Mdet(

Evaluate emittance with:

Compare Compare in in with with outout

Getting at e.g. Getting at e.g. x’t’x’t’ is essentially impossibleis essentially impossible with multiparticle bunch with multiparticle bunch measurements measurements

Each spectrometer measures 6 parameters per particle x y t x’ = dx/dz = Px/Pz

y’ = dy/dz = Py/Pz t’

=dt/dz =E/Pz

G4MICE simulation of Muon traversing MICE

NOW 2006 - Otranto

1. must be sure particles considered are muons throughout

a) reject incoming e, p, => TOF 2 stations 10 m flight with 70 ps

resolution b) reject outgoing e => Cerenkov + Calorimeter 2. measure 6 particle parameters i.e. x,y,t, px/pz , py/pz , E/pz

3. measure widths and correlations … resolution in all parameters must be better than 10%

of width at equilibrium emittance (correction less than 1%)

meas = true+

res = true [ 1+ (res/ true

)2 ] (n.b. these are r.m.s.!)

4. robust against noise from RF cavities

=>

Statistical precision 105 muons out/ in ) = 10-3 in ~ 1 hour Systematics!!!!

Spectrometer system requirements

NOW 2006 - Otranto

B

Baseline tracker5 planes of scintillating fiber tracker with 3 double layers. passive detector + fastgood for RF noise

Very small fibers needed to reduce MSLittle light VLPC readout (D0 experience)

Mice: tracker

Must measure muon momenta & positions

KEK TB Data: Residual Distribution

DATADATA MCMC

KEK TBTracker

1T BESS Magnet

TOF0 TOF1

Ckov1

IronShield

TOF2EMCal

ISISBeam

DiffuserProtonAbsorber

IronShield

Apparatus: PID overview

In the cooling channel muons can be contaminated by •Pions in the incoming beam (muons parents)

•Electrons in the outgoing beam (muon decay products) PID

NOW 2006 - Otranto

MICE: Particle ID

• Upstream:– TOF0/1 hodoscopes

with 10m path, ~60 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– TOF2 hodoscope– Calorimeter for MIP vs

E.M. Shower

TOF2Cal

Frascati TB – TOF & CAL

TOF stationEMCAL

Emittance measurement

from Geant-4 simulations

IEEE 2004 - Roma

-

STEP I

STEP II

STEP III

STEP IV

STEP V

STEP VI

PHASE 1 (funded): start October 2007

•Characterize beam

•Calibrate spectr I

PID + Tracker

+Solenoid

2008 ->

~ 2008

2009?

NOW 2006 - Otranto

MICE at RAL

Site 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

MANX (Muon collider And Neutrino factory eXperiment)

• Proposed follow-up of MICE to obtain large cooling factors (~0.5) in few meters, using graded B fields to mach decreasing p

• Optimization under study, proposal submitted to FNAL (May 2006)

NOW 2006 - Otranto

Summary and outlook

“ Neutrino Oscillations provide us with exciting experimentally driven science. We might be in for big surprises. Neutrino Factories offer a new type of neutrino beam with impressivestatistical and systematic precision, and flexibility. If 13 is smaller than O(0.01) they will offer a way forward … but only if we invest in the R&D so that the option exists when the time comes. “

• As an example, R&D on muon cooling is

a critical point (MICE at RAL)

• Enthusiastic R&D is ongoing, and a lot has

already been accomplished