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PRISM-FFAG
Akira SATO
Osaka University
FFAG03@KEK2003/7/7
ContentsContents
n Physics motivation® Lepton flavor violating process
n PRISM overviewn Construction of the PRISM-FFAG® RF design® Magnet design
n Summary
Physics motivation
FFAG03@KEK2003/7/7
10- 1 4
10- 1 2
10- 1 0
10- 8
10- 6
10- 4
10- 2
1940 1950 1960 1970 1980 1990 2000
Upper limits of Branching Ratio
Y e a r
KL0 Æ me
K+ Æ pme
mAÆeA
m Æ eee
m Æ eg
History of LFV Search limits
Search forSearch forthe Lepton Flavor Violating Processthe Lepton Flavor Violating Process
n No evidence so far for chargedlepton
n Limits have been improvedsteadily® two orders of magnitude
per decaden Sensitivities are superb in muon
systems
n Getting harder® To obtain/handle more
intense muon
New physics beyond the standard model
FFAG03@KEK2003/7/7
LFV in SUSY GUTLFV in SUSY GUT
n MECO@BNL,n MEG@PSI®Equivalent sensitivity
n Future experiment will cover most of
parameter spacewith PRISM
Hisano et al.
FFAG03@KEK2003/7/7
mÆmÆee conversion in a conversion in a Muonic Muonic AtomAtom
n muonic atom (1s state)
n neutrinoless muon nuclear capture (= m-e conversion) physics beyond the Standard Model
muon decay in orbit
nucleus m-
nuclear muon capture
lepton flavors changes by one unit.
A negative muon stopped in some material :
Signal :Monochromatic electron 104.6MeV
FFAG03@KEK2003/7/7
Requirements to a muon beamRequirements to a muon beamfor a next-generation me conversion searchfor a next-generation me conversion search
n High Intensity® The potential sensitivity achievable in searches for rare processes is ultimately limited
by the number of muons available. The muon beam intensity of 1011-1012 μ-/secshould be required, yielding about more than 1020μ- per year.
n High Purity® Beam contaminations are necessary to be removed, to reduce any background associated
with them. It is already shown that the past experiments like SINDRUM-II have alreadyseen a background event just above the signal region, and they suspect that it comes frompion contamination in a beam through radiative pion capture. Therefore, it is the mostimportant to reduce pion contamination in a beam.
n Narrow Energy Width® Narrow energy spread of the beam will allow a thin muon stopping target to improve the
momentum resolution of e- detection, which is limited by energy loss in the muonstopping target.
n High Resolution Spectrometer® To improve the intrinsic momentum resolution in an e- spectrometer, it is critical to
construct a thin tracking chamber system.
PRISM overview
FFAG03@KEK2003/7/7
PRISMPRISMPPhase hase RRotated otated IIntense ntense SSlow low MMuon sourceuon source
n intensity :1011-1012m±/sec
n muon kinetic energy :20 MeV (=68 MeV/c)® range = about 3 g
n kinetic energy spread : ±0.5-1.0 MeV® ±a few 100 mg range width
n beam repetition :about 100Hz
secondary muon beam channelHigh intensity Powerful proton driver Superconducting Solenoid MagnetHigh purityNarrow energy spread Phase rotation in FFAG
dedicated for the stopped muonexperiments.
FFAG03@KEK2003/7/7
PRISM layoutPRISM layoutn Pion capture sectionn Decay sectionn Phase rotation section
FFAG advantages:n synchrotron oscillation
® need to do phase rotation
n large momentum acceptance® necessary to accept large momentumdistribution at the beginning to do phase rotation
n large transverse acceptance® muon beam is broad in space
Ring advantages:n reduction of # of rf cavitiesn reduction of rf power consumptionn compact
not in scale
FFAG as a phase rotator
FFAG03@KEK2003/7/7
Phase RotationPhase Rotationmethod to achieve a beam of narrow energy spreadmethod to achieve a beam of narrow energy spreadn Phase Rotation = decelerate
particles with high energy andaccelerate particle with lowenergy by high-field RF
n A narrow pulse structure (<1 nsec)of proton beam is needed toensure that high-energy particlescome early and low-energy onecome late.
FFAG03@KEK2003/7/7
rrin=460
rout=550cm
Half gap = 10 x (500/r)5 cm
m-
n GEANT3.21 simulation® FFAG Acceptance, Phase rotation® Muon yield, background rate
n Field gradient was made by gap size.n Magnitude of the field
® D : Bz = -0.0717(r(m)/r0)5 (T)® F : Bz = +0.435(r(m)/r0)5 (T)
® r0 = 5 m for 68MeV/c
n Using TOSCA 3D magnetic field map
1 Cell = 45.0 deg.Straight sect. = 16.49 D = 2.46 FD間 = 0.10 F/2 = 3.00
Simulation studies of phase rotator
DFD Triplet Magnet
FFAG03@KEK2003/7/7
012345
Sinusoidal or Saw-tooth Sinusoidal or Saw-tooth
n RF : 5MHz, 128kV/m
ΔE/E = 20MeV+12%-10%
012
3
4
5
n RF : 5MHz, 250kV/m
ΔE/E = 20MeV+4%-5%
FFAG03@KEK2003/7/7
Phase Rotation Simulation:Phase Rotation Simulation:Horizontal Phase SpaceHorizontal Phase Space
Initial Phase
After 1 turn
After 2turns
After 3turns
After 4 turns
After 5turns
54.4 61.2 68.0 74.8 81.6MeV/c
FFAG03@KEK2003/7/7
Pulsed Proton Beam Facility at J-PARCPulsed Proton Beam Facility at J-PARC
50GeV-PS at J-PARCn High intensity 0.75 MW
® 1014proton/sec® Upgradable to 4x1014proton/sec
n A narrow bunched : for phase rotation
New Fast extraction line is necessaryLOI was submitted to J-PARC Request for A Pulsed Proton Beam Facility at J-PARC PRISM/PRIME, EDM ,g-2, Antiproton, NuFactJ
Fast Extraction
Slow Extraction
1ms 100 pulse
0.1s
Kicker
100 Hz is feasible
LOIs are available from :http://psux1.kek.jp/~jhf-np/LOIlist/LOIlist.html
FFAG03@KEK2003/7/7
Muon LFVMuon EDMMuon g-2
Pulsed Proton Beam Facility at J-PARC (cont.)Pulsed Proton Beam Facility at J-PARC (cont.)
FFAG03@KEK2003/7/7
Application List with PRISMApplication List with PRISM
n Particle, Nuclear Physics® Lepton flavor violation
n me conversion, PRIMEn m+ m- conversion
® m life time® m edm® g-2
n Material Science®Muonic X-ray, m sR
n Archeology
n Life science
® Living cell
® Brain scan
FFAG03@KEK2003/7/7
Staging scenarioStaging scenario
n Muon Factory (PRISM,g-2)® Muon LFV® Muon g-2 (3 GeV/c beam line)
n Muon Factory-II (PRISM-II,g-2)® Muon EDM® Muon g-2 (6 GeV/c beam line)
n Neutrino Factory® Based on 1 MW proton beam
n Neutrino Factory-II® Based on 4.4 MW proton beam
n Muon Collider
Physics outcomeat each stage
FFAG03@KEK2003/7/7
Muon Acceleration based ona series of FFAGs
FFAG-based Muon AccelerationFFAG-based Muon Acceleration
n FFAG Acceleration® Large Acceptance (eH,V, dp/p)® Muon cooling is not
mandatory (better ifavailable).
n Advantages® Costs saving
n Small # of RF cavitiesn no cooling needed.
® Simple and compact® Less R&D components
n Four FFAG rings
FFAG03@KEK2003/7/7
Neutrino Factory at J-PARCNeutrino Factory at J-PARC
Schematic Layout of Nufact-J at J-PARC
Construction ofthe PRISM-FFAG
FFAG03@KEK2003/7/7
PRISM layoutPRISM layoutn Pion capture sectionn Decay sectionn Phase rotation section
FFAG advantages:n synchrotron oscillation
® necessary to do phase rotation
n large momentum acceptance® necessary to accept large momentumdistribution at the beginning to do phase rotation
n large transverse acceptance® muon beam is broad in space
not in scale
FFAG as a phase rotator
A budget for the PRISM-FFAG has been approved !FY2003-FY2007
FFAG03@KEK2003/7/7
n To demonstrate® Phase rotation® Muon acceleration® (Muon ionization cooling)
n R&D components® RF with high
n 5MHz, 250kV/m® Large aperture Magnet
n multi coil
Construction of the PRISM-FFAG Construction of the PRISM-FFAGWe will construct a full size PRISM-FFAG
0 20 m5 10 15 05
10
15
Magnet PS
RF PS
RF AMP
Injection system
Extraction
Vacuum Pump
Only 1 RF cavity and 1 kicker will be constructed.Future budget -> Other RFs and kicker to upgrade to the full spec.
FFAG03@KEK2003/7/7
J-PARC
FFAG03@KEK2003/7/7
MA(Magnetic Alloy) CavityMA(Magnetic Alloy) Cavity for high field gradient (~300kV/m) at 5MHzfor high field gradient (~300kV/m) at 5MHz
n MA will be used for J-PARC synchrotron RF cavitiesn Characteristics of MA® Thin Tape , 18 mm® High Field Gradient
n Voltage limit: Brf <Bsat. (1T) and Voltage per layer < 5 V
® High Curie Temperature® Large core, Rectangular Shape® Large permeability(about 2000 at 5MHz)® Original Q value is small(0.6).® High Q is possible by cut core configuration® Thickness -35mm (50mm in future)
FFAG03@KEK2003/7/7
High Gradient CavityHigh Gradient Cavity
1.00E+09
1.00E+10
1.00E+11
1 10 100 1000 10000Brf[Gauss]
up'Q
f
SY2N5C4M2-302FT-smallFT-large
Magnetic Alloys
Ferrites
B=V/wS=25kV/2pX5MHzX5cmX40cm=400Gauss250kV/m 4gap 5MHz
FFAG03@KEK2003/7/7
MA Cavity using Cut CoreMA Cavity using Cut Coren Low Q=large inductance vs. Resonant frequency = 5MHz vs. RF power for 250kV/m
® Resonant capacitance > 50-100 pF by structure® Large inductance in case of no cut MA (not good).
n Can be reduced by using cut core
n Solution® Q=1 at 5MHz with Cut Core (1.5mm gap)
n C=100pF and Rp=500 W /gapn Or C=50 pF and Rp=1 k W/gapn To obtain 40kV/gap, 800kW is necessary.
|Z|
0
20
40
60
80
100
120
140
160
180
0 5 10 15
frequency(MHz)
Impe
danc
e (O
hm)
H=1H=2
Need a model cavity to confirm.Measured using a core for J-PARC cavity
FFAG03@KEK2003/7/7
PRISM RFPRISM RF plan planAnode PS
Clover
cavity cavity cavity cavity
HeaterSG
AMPcondenser
AMPcondenser
AMPcondenser
AMPcondenser
driveAMP
Cooling
# of cores
Impedance
Gaps/cavity
Field gradient
Power tube
Air cooling
4 cores /gap(2.5-3cmcore)
1k W/gap 以上
1 gaps, 31.25-kV/gap, 25cm
62.5- kV/cavity250- kV/m
EIMAC 4CW150KDC35-40kV900-kW(peak)
PRISM RF Plan
FFAG03@KEK2003/7/7
FFAG03@KEK2003/7/7
MA coreMA core
MA core for 150MeV FFAG
1.7m x 0.985m x 30mm
FFAG03@KEK2003/7/7
Multi coil typen demerit
® Not easy to design® Needs current control
n Merit® Flat gap, large gap→large acceptance
® k-value changeable
Pole shape typen merit
® Established scheme® Easy to design
n demerit® Has small Gap
→acceptance is limited by gapsize
® k-value unchangeable
PRISM-FFAG MagnetPRISM-FFAG Magnet
PoP150-MeV
PRISM-FFAG
New
FFAG03@KEK2003/7/7
X400.0 X450.0 X550.0 X600.0 X650.0
Y-50.0
Y50.0
Y100.0
Z0.0
Z50.0
Z100.0
Z150.0
Z250.0
Z300.0
Z350.0
X400.0 X450.0 X550.0 X600.0 X650.0
Y-100.0
Y-50.0
Y50.0
Y100.0
Z
X400.0 X450.0 X550.0 X600.0 X650.0Y
Z100.0
Z150.0
Z250.0
Z300.0
Magnet design is undergoing.
FFAG03@KEK2003/7/7
Acceptance SimulationsAcceptance Simulations
LargeLarge
FFAG03@KEK2003/7/7
0 20 m5 10 15 05
10
15
Magnet PS
RF PS
RF AMP
Injection system
Extraction
Vacuum Pump
Schedule of the PRISM-FFAG constructionSchedule of the PRISM-FFAG constructionn FY2003
® Lattice design, Magnet design® RF R&D
n FY2004® RFx1gap construction & test® Magnetx1 construction & field
meas.n FY2005
® RFx4gap tuning® Magnetx7 construction® FFAG-ring construction
n FY2006® Commissioning® Phase rotation
n FY2007® Muon acceleration® (Ionization cooling)
Important first step to Neutrino Factory
FFAG03@KEK2003/7/7
SummarySummaryn PRISM® Super muon beam with new technology for stopped muon
experiments.® High intensity, high purity and narrow energy spread muon
beamn Staging Scenario to NuFact and muon collider® a important step for the future muon physics and the NuFact.
n A budget for the PRISM-FFAG has been approved. The PRISM-FFAG will be constructed by the end of 2007.® RF construction will start soon.® Lattice and magnet design will be finalized by the end of this
year.
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