mice: the first cooling frontier
DESCRIPTION
MICE: The First Cooling Frontier. V. Blackmore 18 th May, 2010. Summary. Physics at a NF Benefits of a Muon Collider Creating and Cooling Muons MICE Future. 2/20. Physics at a NF. Neutrino flavours are a superposition of mass eigenstates : - PowerPoint PPT PresentationTRANSCRIPT
MICE: THE FIRST COOLING FRONTIER
V. Blackmore
18th May, 2010
SUMMARY
Physics at a NFBenefits of a Muon ColliderCreating and Cooling MuonsMICEFuture
2/20
PHYSICS AT A NF Neutrino flavours are a superposition of mass
eigenstates:
Measure sin2213, even if 13 is small. Determine mass hierarchy. Search for CP violation in the lepton sector.
3
2
1
231313122323121323121223
231323131223122313121223
1312131312
ccsscescsccess
scssseccsscesc
ssccc
ii
iie
phase violatingCP
sin
cos
ijij
ijij
s
c
m1
m3
m2
or
3/20
Search for “wrong sign” muons: An initial beam of +, produces 50% e and 50%
Clean experimental signature and extremely low backgrounds
Can measure values of sin2213 down to O(10-4)
NF PHYSICS SENSITIVITY
N HadronShower
ee
ee
e
No oscillation With oscillation
CP1
e
e
N
N
Figure from FNAL-TM-2259
4/20
NF AND MUON COLLIDER COMPONENTS Bright, intense neutrino beams and step
towards a muon collider…
NeutrinoFactory
MuonCollider
Image from M. Zisman, Muon Collider Physics Workshop 2009
5/20
Image from M. Zisman, Muon Collider Physics Workshop 2009
BEN
EFIT
S O
F A
MU
ON
CO
LLID
ER
• Muons suffer little synchrotron radiation loss.
• Smaller energy spread at Interaction Point for precision energy scans
• RF (expensive!) used efficiently, giving a compact footprint.
• ratio makes the Higgs coupling 40’000 larger.
emm
6/20
CREATING MUONS
p
Target Decay Channel
To
Acc
eler
ator
Resulting muon beam has a large spread in energy and momentum.
This is difficult to accelerate!(Plus, they don’t live long...)
p
p
7/20
e
LIOUVILLE’S THEOREM
Emittance = area of phase space ellipse
xp
zpxp
p
p
p
8/20
LIOUVILLE’S THEOREM
“The particle density in phase space is constant unless acted on by non-conservative force.”
xxxx xzxxzxz 22 )()(2)(
Emittance = constant
9/20
COOLING
We must violate Liouville’s Theorem!...not that it hasn’t been done before.
Cooling is a reduction in emittance.
10/20
TRADITIONAL COOLING
Electrons in a damping ring
Ions cooled by pre-cooled electron beam
Amplifier
Transverse Pickup
TransverseKicker
Stochasticcooling
Muons are too heavy.
Muon is short lived.
cool
ing
11/20
IONISATION COOLING
Absorber
RFAbsorber
RF
Largeemittance
Small(er)emittance
12/20
MUON IONISATION COOLING EXPERIMENT
Aim: Build a section of cooling channel Master engineering and operation Measure cooling with high precision
Experience feeds back into NF and collider design
13/20
MICE HALL AT RAL
14/20
Cooling is balanced by multipleCoulomb scattering
Equilibrium emittance = minimum emittance a material can provide:
Low (strong focusing), large X0 and dE/dz (H2 is best)
XmEEN
dz
dE
dz
d n
0rel3
2
)GeV 014.0( 2
2rel
1
COOLING vs. HEATING
dz
dEXm
n
0rel2
GeV 014.02
equil ,
Cooling Heating
15/20
THE COOLING CHANNEL
16/20Liquid Hydrogen
AbsorberFocus Coils RF
MIC
E M
AG
NETIC
FIE
LD
o Muons produced with large emittance
o Need to contain beam and provide tight focussing at absorbers
o SFoFo lattice
o Magnetic field reverses at absorbers to prevent build-up of canonical angular momentum.
matched in tracker
abs = 42cm
Image from M. Rayner, MICE Collaboration Meeting, March 2010
17/20
TH
E R
EA
L M
ICE B
EA
M
o The current MICE muon beam.
o Characterised using the TOFs by M. Rayner (Oxford)
Images from M. Rayner, MICE Collaboration Meeting, March 2010
3 fit3 fit
Preliminary!
18/20
CO
OLIN
G IN
MIC
E
o Real beam simulations
o Beam inflated by diffuser
o Emittance reduced in absorbers.
o Energy replaced by RF
TOF
Diffuser
Absorber
RF
Absorber
Absorber
RF
MICE should work!
Preliminary!
19/20
Images from M. Rayner, MICE Collaboration Meeting, March 2010
THE FUTURE
Image from B. Palmer, Muon Collider Physics Workshop 200920/20
THE FUTURE
20/20
EXTRA
LIOUVILLE’S THEOREM
xxxx xzxxzxz 22 )()(2)(
rms,
2
rms,
rms,
2
x
xx
x
xxx
x
xx
xx
x
x
x
x
xx
xxx
x
NEUTRINO OSCILLATIONS
Suppose neutrinos {1, , } have different masses {m1, m2, m3}. Each neutrino flavour is a mix of these. E.g. in a two flavour system:
Probability for a to oscillate to e is:
2
1
cossin
sincos
e
parameter mixing neutrino 2sin
energy, Neutrino
detector, tosource from Distance
27.1sin2sin
2
22
21
2
222
mmm
E
L
E
LmP e
4/22