Neutrino Factories and Muon Ionization Cooling Channels

1
Neutrino Factories and Muon Ionization Cooling
Channels

• D. Errede
• HETEP University of Illinois
• 17 March, 2003

2
Why build a Neutrino Factory? (Physics, of course)
What does a Neutrino Factory look like?
In particular, what is an ionization
cooling channel? What has the University of
Illinois been doing with respect to a cooling
channel?
3
(No Transcript)
4
The Physics of Neutrinos

• Neutrino masses
• (pattern of the all fermion masses)
• Neutrino oscillation parameters
• (fill in the CKM matrix for leptons)
• CP Violating processes in the Lepton Sector
• (origin of baryon-antibaryon asymmetry in
• our universe?)
• GUTS relating properties of quarks and leptons
• Is there a grand unified scheme?

5

6
The Physics of Neutrinos
Standard form for Mixing Matrix connecting weak
and mass eigenstates Q12, Q23, Q13, d are the 4
real parameters that describe the mixing d
0 implies CP violation. (phase between 0 and 2p
)
7
The Physics of Neutrinos

• Connect two weak eigenstates with the
• evolution operator involves Hamiltonian H0
• Use two assumptions
• m1 lt m2 ltlt m3 and
• dM2 dm2atm dm232 dm231 we get

And something similar but more complicated for nm

8
The Physics of Neutrinos

• The sign of dm2 solar neutrinos
• Matter effects MSW (Mikheev, Smirnov,
  Wolfenstein)
• ne interacts with electrons in matter through the
  charged current interaction. This adds a term to
  the evolution operator.
• There is a resonance in matter near a 1 for
  typical values of sin22q (10-3 - 10-2)
• a depends on Ne, GF, En, dm2 .
• q q12 , q13

9
The Physics of Neutrinos

• The resonance applies to neutrinos for positive
  dm2 and antineutrinos for negative dm2.
• Thus we can get the mass hierarchy.
• -----m3
• 
  -----------m2
• 
  -----------m1
• OR
• -----------m2
• -----------m1
• -----m3

10
The Physics of Neutrinos
3 Plausible Sets of Values
1 2 3
J - Jarlskog factor a measure of CP violatioin
11
The Physics of Neutrinos CP VIOLATION

• J c12 c132 c23 s12 s13 s23 sind
• Jarlskog J-factor a measure of CP violation
• CP Operation C(neL) neL
• P(neL) neR
• CP Violating Process
• For example in
  vacuum

12
The Physics of Neutrinos
CP Violating Processes in the Lepton Sector Why
is this interesting/fun/exciting? A possible
explanation for Baryogenesis. (So far CP
violating processes in the b quark sector are
insufficient to explain baryogenesis)
A SCENARIO Heavy Neutral Leptons
Majorana neutrinos through see-saw mechanism
produces a light neutrino pair and a heavy
neutrino pair. N e- H or e H-
(both massless particles because this is occuring
before EW symmetry breaking).
13
The Physics of Neutrinos
CP Violating processes provides excess of
e,m,t over e-,m-,t- before EW phase
transition. Andrei Sakharov says we also need
non-equilibrium conditions so that these
processes are not driven to equalize the
numbers. Standard Model nonperturbative
processes violate B, L, but conserve B-L. Churns
leptons into baryon material.
Thank you
Boris Kayser
14
The Physics of Neutrinos
CP Violation in the Lepton Sector What would
this have to do with CP violating processes in
the low mass neutrino sector? We dont know, but
certainly CP violation in leptons at low mass
makes CP violation in leptonic interactions at
high mass scales more plausible.
GUTs one can also imagine unifying quarks and
lepton such that their CKM matrices are also
related. We wont understand this until all the
parameters are measured.
15
Neutrino Factory

1. High intensity beam on target to produce
   particles (ps) for a secondary beam. - Proton
   Driver Target
2. Collects ps, allow them to decay into muons,
   spread bunch (large DE) and then perform phase
   rotation Drifts Induction Linacs
3. Reduce energy (and emittance) between induction
   linacs Minicooling
4. Adiabatically change from one lattice to the
   next lattice Matching Sections
5. Divide long bunch (100 m) into short bunches
   that cooling section can handle - Buncher

16
Neutrino Factory

• 6. Reduce beam emittance Cooling Channels
• 7. Accelerate to energy and emittance size that
  the next recirculating accelerators can handle -
  Linac
• Accelerate from 2.8 GeV to 20 GeV Recirculating
  Linear Accelerators (RLAs)
• Circulate muons and let some decay on production
  straight Muon Storage Ring
• Make measurements on neutrino interactions Near
  and Far Detectors

17
(No Transcript)
18
Neutrino Factory Proton Driver

• Based on Feasibility Study 2 version of a
  neutrino factoryhence set at Brookhaven Natl Lab
  
• AGS proton driver uses existing ring, bypasses
  existing booster and introduces 3 new
  superconducting linacs.

19
Neutrino Factory AGS Proton Driver Parameters
Total beam power (MW) 1
Beam Energy (GeV) 24
Average beam current (mA) 42
Cycle time (ms) 400
Number of protons per fill 1 x 1014
Average circulating current 6
No. of bunches per fill 6
No. of protons per bunch 1.7 x 1013
Time between extracted bunches (ms) 20
Bunch length at extraction, rms (ns) 3
Peak bunch current (A) 400
Total bunch area (eV-sec) 5
Bunch emittance, rms (eV-sec) 0.3
Momentum spread, rms 0.005
20
AGS Proton Driver Layout
21
Neutrino Factory Superconducting Linacs
Period
Configuration of the cavities within the
cryo-modules
22
AGS Injection Parameters
Injection turns 360
Repetition rate (Hz) 2.5
Pulse length (ms) 1.08
Chopping rate () 65
Linac average/peak current (mA) 20/30
Momentum spread /- 0.0015
Norm. 95 emittance (pmm rad) 12
RF Voltage (kV) 450
Bunch length (ns) 85
Longitudinal emittance (eV-s) 1.2
Momentum spread /- 0.0048
Norm. 95 emittance (pmm rad) 100
23
AGS Proton Driver
Bunch pattern for using harmonic 24 to create 6
bunches
24
Neutrino Factory Target

• Energy on target 24 GeV, baseline beam power 1
  MW,
• Pion momentum distribution peaks at 250 MeV,
• ltpTgt 150 MeV ? large angles coming off
  target.
• Capture with 20 Tesla solenoid (r 7.5cm, pTmax
  225 MeV).
• Actually a horn which tapers to 1.25 T (r
  30cm,
• pTmax 67.5 MeV)
• (A horn converts transverse momentum into
  longitudinal momentum.)
• Target High Z ? maximize yield of p/p
• Goal of 2 1020 muon per year (107
  seconds) decaying in detector direction, 50 kT,
  1800 km away.

25
Neutrino Factory Target Z
26
Neutrino Factory Target

• Liquid Hg jet target chosen for maximum yield.
• Need to handle 1 4 MW beams.
• Want vjet 30m/s to resupply Hg. Tests
  achieved 2.5 m/s to date. ( 30m/s only
  resupplies mercury before next
• bunch on average 6 x 2.5 Hz 15/sec )

27
Target RD for MW-Scale Proton Beams
27

• Carbon Target tested at AGS (24 GeV, 5E12 ppp,
  100ns)
• Probably OK for 1.5 MW beam limitation target
  evaporation

• Target ideas for 4 MW Water cooled Ta Spheres
  (P. Sievers), rotating band (B. King),
  conducting target, Front-runner Hg jet

• CERN/Grenoble Liquid Hg jet tests in 13 T
  solenoid
• Field damps surface tension waves

13 Tesla
0 Tesla

• BNL E951 Hg Jet in AGS beam
• Jet (2.5 m/s) quickly re-establishes itself.
  Will test in 20T solenoid in future.

t 0 0.75 ms 2 ms
7 ms 18 ms
28
Neutrino Factory Drifts and Induction Linacs

• Beam has large energy spread.
• Drift allows beam to spread out to a long bunch
  length.
• Induction linacs accerlate late muons (lower
  energy) and decelerate early muons (higher
  energy).

29
Neutrino Factory Drifts and Induction Linacs
30
Neutrino Factory Drifts and Induction Linacs
31
Neutrino Factory Drifts and Induction Linacs
32
Neutrino Factory Drifts and Induction Linacs
33
(No Transcript)
34
Neutrino Factory Drifts and Induction Linacs
35
Neutrino Factory Minicooling in Drifts and
Induction Linacs
36
Neutrino Factory Buncher and Cooling Channel
In order to fit muon beam into cooling lattice
the Buncher separates the 100m long trail of
muons into rf buckets. The cooling channel
(Pnominal 200 MeV) then reduces the transverse
emittance to a level acceptable for acceleration
to 20 GeV.
37
Momentum-time distributions through the buncher
38
Neutrino Factory Buncher and Cooling Channel
39
Momentum-time distributions through the buncher
40
(No Transcript)
41
Neutrino Factory Cooling Channel Lattice Cell
42
Neutrino Factory Cooling Channel
43
Neutrino Factory Cooling Channel
44
Neutrino Factory Cooling Channel
45
Neutrino Factory Cooling Channel
46
Neutrino Factory Cooling Channel
47
Neutrino Factory Cooling Channel
48
Neutrino Factory Cooling Channel
49
Absorber Forced Flow Design
50
Approximate Equation Transverse Emittance in a
step ds along the particles orbit
First term is the Ionization Energy Loss
(Cooling) Term Second term is the Multiple
Scattering (Heating) term
51
Absorber Aluminum Window Pressure/Burst Testing
52
MUCOOL UIUC Absorber Instrumentation Project
Zach Conway Mike Haney Debbie Errede
53
MUCOOL RF RD
53
Need high gradient cavities in multi-Tesla
solenoid field
Concept 1 open cell cavity withhigh surface
field

• 805 MHz Cavity built tested
• Surface fields 53 MV/m achieved
• Large dark currents observed
• Breakdown damage at highest gradients
• Lots of ideas for improvement

High Power 805 MHz Test Facility12 MW
klystron Linac-type modulator controls X-Ray
cavern 5T two-coil SC Solenoid Dark-current
X-Ray instrumentation
Concept 2 pillbox cavity - close aperture with
thin conducting foil
805 MHz Cavity built being tested
54
Neutrino Factory Cooling Channel
55
Construction of FODO Quad Cooling Cell

• 1/2
  1/2
• abs F rf D rf
  F rf D abs
• COOLING CELL PHYSICAL PARAMETERS
• Quad Length 0.6 m
• Quad bore 0.6 m
• Poletip Field 1 T
• Interquad space 0.4 - 0.5 m
• Absorber length 0.35 m
• RF cavity length 0.4 - 0.7 m
• Total cooling cell length 4 m
• The absorber and the rf cavity can be made
  longer if allowed to extend into the ends of the
  magnets.
• Or, more rf can be added by inserting another
  FODO cell between absorbers
• In this design
• For applications further
  upstream at larger emittances, this channel can
  support a 0.8 m bore, 0.8 m long quadrupole with
  no intervening drift without matching to the
  channel described here.

56
Quad Cooling Beam Dynamics Group UIUC Debbie
Errede, Kyoko Makino, Kevin Paul MSU Martin
Berz FERMILAB Carol Johnstone, A. Van Ginneken

• MOVIE
• Quad cooling movie / Kyoko Makino
• GSview - View fit window full screen page
  down - escape

57
Recirculating Linear Accelerators (RLAs)
58
Recirculating Linear Accelerators (RLAs)
Preaccelerator
59
Recirculating Linear Accelerators (RLAs)
Preaccelerator
60
Recirculating Linear Accelerators (RLAs)
Preaccelerator
61
Recirculating Linear Accelerators (RLAs)
Preaccelerator
62
Recirculating Linear Accelerators (RLAs)
Preaccelerator
63
Recirculating Linear Accelerators (RLAs)
Preaccelerator
64
Recirculating Linear Accelerators (RLAs)
Injection Chicane from Linac to RLA
65
Recirculating Linear Accelerators (RLAs) Arcs
66
Recirculating Linear Accelerators (RLAs) Arcs
67
(No Transcript)
68
Recirculating Linear Accelerators (RLAs)
69
Recirculating Linear Accelerators (RLAs)
70
Muon Storage Ring

• Maximize number of muon on production straight
• fs Ls/C
• Minimize length of arcs
• Real Estate is an important issue here.
• Larger energy decreases angular beam spread
  (1/g)
• allowing more neutrinos on target detector

71
(No Transcript)
72
Real Estate is an important issue here! ARCS
73
COSY Kyoko Makino (UIUC), Martin Berz (MSU)
Tracking performed on a single arc cell.
74
COSY Kyoko Makino (UIUC), Martin Berz (MSU)
75
Same Lattice with End Fields added
76
(No Transcript)
77
Conclusions

• Neutrino physics is fascinating, beautiful and
  accessible.
• A Muon Collaboration exists that has done two
  feasibility
• studies on neutrino factory designs and RD
  on targetry,
• absorbers, 800 (200) MHz NCRF cavities,
  solenoid
• magnets, and constructing a test area off of
  the Fermilab
• 400 MeV/c proton linac.
• Design studies for Ring Coolers, FFAG
  machines,
• Emittance Exchange are ongoing.
• Alternative technologies pursued at CERN and in
  Japan.
• Future plans include the construction of a
  cooling channel
• lattice cell to be tested in a low intensity
  muon beam at
• Rutherford Labs near Oxford, England.