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ILC Positrons. Positron Production for the ILC. J. C. Sheppard SLAC July 26, 2007. Positron Production for the ILC. What is the ILC e+ System How to make e+ Something about polarization Who works on this stuff What are the design issues What next. Parameter Reference Upgrade - PowerPoint PPT Presentation
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Slide 1July 26, 2007 Toward the ILC
AmericasILC Positrons
J. C. Sheppard
SLAC
July 26, 2007
Positron Production for the ILC
Slide 2July 26, 2007 Toward the ILC
Americas
Positron Production for the ILC
What is the ILC e+ System
How to make e+
Something about polarization
Who works on this stuff
What are the design issues
What next
Americas
Slide 3July 26, 2007 Toward the ILC
THE INTERNATIONAL LINEAR COLLIDER (ILC)
Parameter Parameter ReferenceReference Upgrade Upgrade
Beam Energy Beam Energy (GeV)(GeV) 250 250 500 500 RF gradient RF gradient (MV/m)(MV/m) 28 28 35 35 Two-Linac length Two-Linac length (km)(km) 27.00 27.00 42.54 42.54 Bunches/pulse Bunches/pulse 2625 2625 2625 2625 Particles/bunch Particles/bunch (10(101010)) 2 2 2 2 Beam pulse length Beam pulse length (µs )(µs ) 968 968 968 968 Pulse/s Pulse/s (Hz)(Hz) 5 5 5 5 xx(IP) (IP) (nm)(nm) 543 543 489 489 yy(IP) (IP) (nm)(nm) 5.7 5.7 4.0 4.0 zz(IP) (IP) (mm)(mm) 0.3 0.3 0.3 0.3 δδE E (%)(%) 3.0 3.0 5.9 5.9 Luminosity Luminosity (10(103333cmcm−2−2ss−1−1)) 25.625.6 38.138.1Average beam power Average beam power (MW)(MW) 22.6 22.6 45.2 45.2 Total number of klystrons Total number of klystrons 603 603 1211 1211 Total number of cavities Total number of cavities 18096 18096 29064 29064 AC to beam efficiency AC to beam efficiency (%)(%) 20.8 20.8 17.5 17.5
Parameter Parameter ReferenceReference Upgrade Upgrade
Beam Energy Beam Energy (GeV)(GeV) 250 250 500 500 RF gradient RF gradient (MV/m)(MV/m) 28 28 35 35 Two-Linac length Two-Linac length (km)(km) 27.00 27.00 42.54 42.54 Bunches/pulse Bunches/pulse 2625 2625 2625 2625 Particles/bunch Particles/bunch (10(101010)) 2 2 2 2 Beam pulse length Beam pulse length (µs )(µs ) 968 968 968 968 Pulse/s Pulse/s (Hz)(Hz) 5 5 5 5 xx(IP) (IP) (nm)(nm) 543 543 489 489 yy(IP) (IP) (nm)(nm) 5.7 5.7 4.0 4.0 zz(IP) (IP) (mm)(mm) 0.3 0.3 0.3 0.3 δδE E (%)(%) 3.0 3.0 5.9 5.9 Luminosity Luminosity (10(103333cmcm−2−2ss−1−1)) 25.625.6 38.138.1Average beam power Average beam power (MW)(MW) 22.6 22.6 45.2 45.2 Total number of klystrons Total number of klystrons 603 603 1211 1211 Total number of cavities Total number of cavities 18096 18096 29064 29064 AC to beam efficiency AC to beam efficiency (%)(%) 20.8 20.8 17.5 17.5
WORLD CollaborationWORLD CollaborationMulti-billion dollar projectMulti-billion dollar projectProposed eProposed e++ee–– linear collider linear collider0.5-1.0 TeV center-of-mass 0.5-1.0 TeV center-of-mass energiesenergiesMajor elementsMajor elements
Electron injectorElectron injectorElectron damping ringElectron damping ringMain electron linacMain electron linacElectron beam delivery to IRElectron beam delivery to IRPositron SourcePositron SourcePositron damping ring(s)Positron damping ring(s)Main positron linacMain positron linacPositron beam delivery to IRPositron beam delivery to IRIRIRDetectors at IRDetectors at IR
Slide 4July 26, 2007 Toward the ILC
Americas
ILC Positron Source Parameters
Parameter Symbol Value Units
Bunch Population Nb 2x1010 #
Bunches per pulse nb 2625 #
Bunch spacing tb 369 ns
Pulse repetition rate frep 5 Hz
Injection Energy (DR) E0 5 GeV
Beam Power (x1.5) Po 300 kW
Polarization e-(e+) P 80(30) %
Slide 5July 26, 2007 Toward the ILC
POSITRON SOURCE DESIGN ISSUES
Drive beamDrive beamElectrons or Electrons or photonsphotons
Photons allow for the possibility of polarized positronsPhotons allow for the possibility of polarized positrons
How are the photons madeHow are the photons madeMulti-hundred GeV electron beam through an undulatorMulti-hundred GeV electron beam through an undulatorCompton back-scattering laser beam on a multi-GeV electron beamCompton back-scattering laser beam on a multi-GeV electron beam
Drive beam phase spaceDrive beam phase space
TargetTargetChoice of materialChoice of materialTarget heat/shock/stressTarget heat/shock/stress
Positron capturePositron captureBeam heatingBeam heatingCapture RFCapture RFCapture magnetic fieldCapture magnetic fieldDamping ring acceptanceDamping ring acceptance
Target vaultTarget vault
Drive beamDrive beamElectrons or Electrons or photonsphotons
Photons allow for the possibility of polarized positronsPhotons allow for the possibility of polarized positrons
How are the photons madeHow are the photons madeMulti-hundred GeV electron beam through an undulatorMulti-hundred GeV electron beam through an undulatorCompton back-scattering laser beam on a multi-GeV electron beamCompton back-scattering laser beam on a multi-GeV electron beam
Drive beam phase spaceDrive beam phase space
TargetTargetChoice of materialChoice of materialTarget heat/shock/stressTarget heat/shock/stress
Positron capturePositron captureBeam heatingBeam heatingCapture RFCapture RFCapture magnetic fieldCapture magnetic fieldDamping ring acceptanceDamping ring acceptance
Target vaultTarget vault
Americas
Slide 6July 26, 2007 Toward the ILC
ILC Layout
ee++ & e & e- - Damping Rings centrally locatedDamping Rings centrally located
positron source uses 150 GeV electron beampositron source uses 150 GeV electron beam
L-band superconducting RF for accelerationL-band superconducting RF for acceleration
ee++ & e & e- - Damping Rings centrally locatedDamping Rings centrally located
positron source uses 150 GeV electron beampositron source uses 150 GeV electron beam
L-band superconducting RF for accelerationL-band superconducting RF for acceleration
Americas
Slide 7July 26, 2007 Toward the ILC
Slide 8July 26, 2007 Toward the ILC
POSITRON PRODUCTION SCHEMES – DRIVE BEAMS
EM Shower
e+ to damping ringsConventional
Undulator-based (from USLCTOS)
W-Re Target
6 GeV e-
Slide 9July 26, 2007 Toward the ILC
COMPTON-BASED POSITRON SOURCE – LASERS
GLC laser power : 9.8 MW peak power per laser bunch ~ 400 kW average power (40kW with use of mirrors)~ 73 GW peak power
ILC bunch structure 2820 * 5 ~= 95 * 150but 2820 bunch pulse trainsmay be able to use mirrors to relax laser parameters
Slide 10July 26, 2007 Toward the ILC
Snowmass 2005 Ring based Compton
Slide 11July 26, 2007 Toward the ILC
ERL based Compton scheme & requirements to lasers
PosiPol2007@LAL23/May/2007
Tsunehiko OMORI (KEK)my talk is inspired by Variola-san's talk at KEK Nov/2006 and Rainer-san's suggestion at SLAC Apr/2004
Slide 12July 26, 2007 Toward the ILC
UNDULATOR BASED POSITRON SOURCE
Need to use ILC electron beam – possible reliability, machine development and commissioning issues
Can use electron source for commissioning
Long helical undulator, small aperturepermanent magnetwarm pulsedsuperconducting
Slide 13July 26, 2007 Toward the ILC
AmericasPositron Source Layout
Slide 14July 26, 2007 Toward the ILC
Americas
Polarized Positrons from Polarized ’s
(Olsen & Maximon, 1959)
Circular polarization of photon transfers to the longitudinal polarization of the positron.
Positron polarization varies with the energy transferred to the positron.
Slide 15July 26, 2007 Toward the ILC
AmericasPhoton Intensity, Angular Dist., Number,
Polarization
Slide 16July 26, 2007 Toward the ILC
AmericasPolarized Positron Production in the
FFTB
Polarized photons pair produce polarized positrons in a 0.5 r.l. thick target of Ti-alloy with a yield of about 0.5%.
Longitudinal polarization of the positrons is 54%, averaged over the full spectrum
Note: for 0.5 r.l. W converter, the yield is about 1% and the average polarization is 51%.
Slide 17July 26, 2007 Toward the ILC
AmericasPhoton Number Spectrum
Number of photons per e- per 1m undulator:Old BCD: 2.578UK1: 1.946; UK2: 1.556; UK3: 1.107Cornell1: 0.521; Cornell2: 1.2; Cornell3: 0.386
Gai and Liu, ANL
Slide 18July 26, 2007 Toward the ILC
AmericasPhoton Spectrum and Polarization of ILC baseline
undulatorResults of photon number spectrum and polarization characteristic of ILC undulator are given here as examples. The parameter of ILC undulator is K=1, u=1cm and the energy of electron beam is 150GeV.
Figure1. Photon Number spectrum and polarization characteristics of ILC undulator up to the 9th harmonic. Only those have energy closed to critical energy of its corresponding harmonics have higher polarization Gai and Liu, ANL
Slide 19July 26, 2007 Toward the ILC
AmericasInitial Polarization of Positron beam at Target
exit(K=0.92 u=1.15)
Gai and Liu, ANL
Slide 20July 26, 2007 Toward the ILC
Americas
Gai and Liu, ANL
ILC Positron Polarization,captured~ 30% Pol
Slide 21July 26, 2007 Toward the ILC
AmericasILC Positron Polarization
In the case of the ILC baseline, the composite polarization of the captured positrons is about 30%. Spin rotation to preserve the polarization in the damping ring(s) is included
To upgrade to higher polarization, the incident photon beam is collimated to remove the low energy, reversely polarized component of the spectrum ( = 1.414). The length of the undulator needs to be increased to compensate for the loss in absolute flux.
Slide 22July 26, 2007 Toward the ILC
AmericasUS Institutions
• Institutions doing substantial work on ILC e+ development– SLAC
• overall coordination & leadership for the RDR• define parameters• target hall, remote handling, activation• beamline optics and tracking• NC L-Band accelerator structures and RF systems• Experiments – E166, FLUKA validation experiment
– LLNL• target simulations (thermal hydraulics and stress, rotordynamics, materials)• target design (testing and prototyping)• pulsed OMD design
– ANL• optics• tracking• OMD studies• eddy current calculations
– Cornell• undulator design, alternative target concepts
Slide 23July 26, 2007 Toward the ILC
AmericasEuropean Institutions
• Institutions doing substantial work on ILC e+ development– Daresbury Laboratory
• EDR leadership• undulator design and prototyping• beam degradation calculations
– Rutherford-Appleton Laboratory• remote handling• eddy current calculations• target hall activation
– Cockcroft and Liverpool University• target design and prototyping
– DESY-Berlin• target hall activation• spin preservation• photon collimation• E166
Slide 24July 26, 2007 Toward the ILC
AmericasILC e+ Collaboration Meeting
Slide 25July 26, 2007 Toward the ILC
AmericasILC Polarized Positron System Technical Issues
1. Demonstrate undulator parameters
2. Demonstrate NC SW structure hi power rf performance
3. Spinning target pre-prototype demonstration
3. Eddy current measurements on spinning target
4. Selection and Technical design of Optical Matching Device
5. System engineering for e+ source remote handling
6. System engineering for photon dump
7. System design compatibility with ILC upgrade scenarios: polarization and energy
Slide 26July 26, 2007 Toward the ILC
AmericasILC Positron EDR Milestones
• Sep 07: Full layout with /4 XMFR OMD
• Dec 07: EDR Scope definition: design depth and breadth, cost, schedule, staff
• Jun 08: Full upgrade scenario: polarization and ILC energy
• Sep 08: OMD selection (dc immersed, pulsed FC, /4 XMFR), Und parameter selection
• Dec 08: Freeze layout, full component and civil specifications (yield, overhead, remote handling, upgrades)
• Jan 09: EDR detailed component inventory
• May 09: First cost review
• Dec 09: Deliver EDR and preconstruction work plan
Slide 27July 26, 2007 Toward the ILC
AmericasILC Positron Design Issues, Undulator
Ne+ = cYLunNe-
c (Adr,Edr,Ac,e+) ~ 15%-25%
Y(E, X0,) ~ 1%-5%
n(K,u) ~ 2
Lu ~ 100 m
Slide 28July 26, 2007 Toward the ILC
AmericasILC Positron Design Issues, Target
FOM =[E/2(1-)/Cv/]/UTS(fatigued)
Thermoelastic stress wrt material strength
Targets break rather than melt
E/mass < 100 J/g
High strength Ti-alloy (Ti6%Al4%V)
Slide 29July 26, 2007 Toward the ILC
AmericasILC Positron Design Issues, Target
Need to spread out the energy deposition
This is done by spinning the target at 100 m/s
Same problem with windows but do not know how to spin
Can imagine an entrance window
Exit window will not survive
July 26, 2007 Toward the ILC 30
ILC RDR Baseline Positron Source
RDR Parameters
Centre of undulator to target: 500m
Active (K=0.92, period=1.21mm) undulator: 147m
Photon beam power: 131kW
Beam spot: >1.7 mm rms
July 26, 2007 Toward the ILC 31
Baseline Target Design• Wheel rim speed (100m/s) fixed by thermal load (~8% of photon beam power)
•Rotation reduces pulse energy density from ~900J/g to ~24J/g
•Cooled by internal water-cooling channel
•Wheel diameter (~1m) fixed by radiation damage and capture optics
•Materials fixed by thermal and mechanical properties and pair-production cross-section (Ti6%Al4%V)
•Wheel geometry (~30mm radial width) constrained by eddy currents.
•20cm between target and rf cavity.
T. P
igg
ott, L
LN
L
Drive motor and water union are mounted on opposite ends of through-shaft.
Slide 32July 26, 2007 Toward the ILC
AmericasTarget Progress
• Baseline target/capture
– RAL, ANL and Cornell have done Eddy current simulation which produce consistent results with multiple codes. Estimates for power dissipation in the target are >100kW for a constant field and are considered excessive.
– Evaluation of ceramic target material is on-going. No conclusions.– Radiation damage of the superconducting coil is still TBD but may not
be worthwhile unless a solution can be found for the eddy currents.– ANL simulation of beam heating in windows shows that an upstream
window is feasible but a downstream window is not.
• Alternative target/capture
– Capture efficiency for the lithium lens focusing and ¼ wave solenoid is still TBD
– Thermal heating and stress for the lithium lens is still on-going.– Thermal stress calculation for the liquid metal target is still on-going
Slide 33July 26, 2007 Toward the ILC
Americas
Capture versus Optical Matching Device Type
From F. Zhou, W. Liu
Pos
itron
Cap
ture
(ar
b. u
nits
)
No OMD
¼ xfrm
Pulsed FC
Immersed
0
0.1
0.2
0.3
0.4
Slide 34July 26, 2007 Toward the ILC
AmericasOptical Matching Device (OMD)
• Optical Matching Device – factor of 2 in positron yield (3 if immersed target)
– DC solenoid before target or pulsed flux concentrator after target
– Pulsed device is the baseline design
• Target spins in the magnetic field of the OMD– Eddy currents in the target – need to calculate power
– Magnetic field is modified by the eddy currents – effect on yield??
• Eddy current mitigation– Reduce amount of spinning metal
– Do experiment to validate eddy current calculations
– Look for low electrical / high thermal conductivity Ti-alloys
– Other materials such as ceramics
– No OMD• Use focusing solenoidal lens (1/4 wave) – lower fields• OMD is upgrade to polarization(??)
Slide 35July 26, 2007 Toward the ILC
AmericasEddy Current Experiment
Eddy current calculation mesh -
S. Antipov, W. Liu, W. Gai - ANL
Proposed experimentLayout at CockcroftInstitute/Daresbury(this summer)
Slide 36July 26, 2007 Toward the ILC
AmericasCalculated Eddy Current Power
0
500
1000
1500
2000
2500
0 500 1000 1500 2000 2500 3000 3500
RPMs
Power, kWatts σ=2.5e6
σ=2.0e6
σ=1.5e6
σ=1.0e6
coppersigma=60e6
Nominal RPMs
TiAlV = 6e5
Slide 37July 26, 2007 Toward the ILC
Americas
Pulsed Flux Concentrator: 7T, 1 ms, 5 Hz
Pulsed Flux Concentrator, circa 1965: Brechna et al.
Slide 38July 26, 2007 Toward the ILC
AmericasOMD Progress
• Plans and Actions (baseline target/capture):– ANL will simulate eddy currents in the pulsed magnet configuration.
– UK will evaluate suitability of non-conducting materials for the target
– Daresbury/Cockroft/RAL will spin a one meter target wheel in a constant magnetic field and will measure the forces.
• Eddy simulations will be calculated and benchmarked against this configuration
• Plans and Actions (alternative targets/capture):– ANL will determine the capture efficiency for ¼ wave focusing optics
and lithium lens.
– LLNL will evaluate the survivability of lithium lens to beam stress
– Cornell will specify an initial design of a liquid metal target. LLNL will calculate the Stress-strain behavior of the outgoing beam window.
Slide 39July 26, 2007 Toward the ILC
CCLRC
Undulator Challenges
High fields Pushing the limits of technology
Short Periods Shorter periods imply higher fields
Narrow apertures Very tight tolerances - Alignment critical
Cold bore (4K surface) Cannot tolerate more than few W of heating per module
Minimising impact on electron beam Must not degrade electron beam properties but have to remove energy from
electrons Creating a vacuum
Impossible to use conventional pumps, need other solution Minimising cost
Minimise total length, value engineering
High fields Pushing the limits of technology
Short Periods Shorter periods imply higher fields
Narrow apertures Very tight tolerances - Alignment critical
Cold bore (4K surface) Cannot tolerate more than few W of heating per module
Minimising impact on electron beam Must not degrade electron beam properties but have to remove energy from
electrons Creating a vacuum
Impossible to use conventional pumps, need other solution Minimising cost
Minimise total length, value engineering
Slide 40July 26, 2007 Toward the ILC
CCLRC
UK Undulator Recent Highlights
Two 12mm period SC undulator prototypes built and tested Period reduced to 12mm from 14mm Better, more reproducible, fabrication technique Full inclusion of iron for the first time
One 11.5mm period SC undulator built and tested Period further reduced to RDR value of 11.5mm New SC wire used (more SC and less Cu) Field strength measured greater than expected, possibly due to increase in SC
content of wire Best ever field quality results (well within spec) Full length prototype will use these parameters
Full length prototype construction started 4m prototype design complete Fabrication has commenced
Undulator impact studies ongoing Emittance growth due to misalignments & wakefields shown to be <2%
Paper on undulator technology choice published by Phys. Rev. ST-AB Paper on vacuum issues submitted to JVSTA
Two 12mm period SC undulator prototypes built and tested Period reduced to 12mm from 14mm Better, more reproducible, fabrication technique Full inclusion of iron for the first time
One 11.5mm period SC undulator built and tested Period further reduced to RDR value of 11.5mm New SC wire used (more SC and less Cu) Field strength measured greater than expected, possibly due to increase in SC
content of wire Best ever field quality results (well within spec) Full length prototype will use these parameters
Full length prototype construction started 4m prototype design complete Fabrication has commenced
Undulator impact studies ongoing Emittance growth due to misalignments & wakefields shown to be <2%
Paper on undulator technology choice published by Phys. Rev. ST-AB Paper on vacuum issues submitted to JVSTA
Slide 41July 26, 2007 Toward the ILC
CCLRC
UK Prototypes
I II III IV V
Former material Al Al Al Iron Iron
Period, mm 14 14 12 12 11.5
Groove shape rectangular trapezoidal trapezoidal trapezoidal rectangular
Winding bore, mm
6 6 6.35 6.35 6.35
Vac bore, mm 4 4 4 4.5
(St Steel tube)
5.23*
(Cu tube)
Winding 8-wire ribbon,
8 layers
9-wire ribbon,
8 layers
7-wire ribbon,
8 layers
7-wire ribbon,
8 layers
7-wire ribbon,
8 layers
Sc wire Cu:Sc 1.35:1 Cu:Sc 1.35:1 Cu:Sc 1.35:1 Cu:Sc 1.35:1 Cu:Sc 0.9:1
Status Completed and tested
Completed, tested and sectioned
Completed and tested
Completed and tested
Completed and tested
Slide 42July 26, 2007 Toward the ILC
CCLRC
Prototype 5
Same parameters as RDR Baseline undulator
11.5 mm period 6.35 mm winding diameter Peak on-axis field spec of
0.86T (10 MeV photons) Winding directly onto copper
tube with iron pole and yoke New wire with more
aggressive Cu:SC ratio of 0.9:1.0
Same parameters as RDR Baseline undulator
11.5 mm period 6.35 mm winding diameter Peak on-axis field spec of
0.86T (10 MeV photons) Winding directly onto copper
tube with iron pole and yoke New wire with more
aggressive Cu:SC ratio of 0.9:1.0
First 500mm long
prototype
Slide 43July 26, 2007 Toward the ILC
CCLRC
1st results from prototype 5 at RAL
Prototype V fi eld profi le
-1
-0.5
0
0.5
1
0 100 200 300 400 500
Z, mm
Fie
ld o
n ax
is, T
Prototype 5 details
Period : 11.5 mmMagnetic bore: 6.35 mmConfiguration: Iron poles and yoke
Measured field at 200A
0.822 T +/- 0.7 %(spec is +/- 1%)
Measurements for Prototype 5
Prototype V training
0
50
100
150
200
250
300
350
0 2 4 6 8 10 12
Magent runup
Que
nch
curr
ent (
A)
23/01/2007
25/01/2007
Quench current 316A
Equates to a field of 1.1 T in bore
RDR value is 0.86 T
80% of critical current (proposed operating point) would be 0.95 T
Slide 44July 26, 2007 Toward the ILC
CCLRC
Summary of Prototype Results
Field on axis vs. Undulator period
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
6 8 10 12 14 16 18
Period, mm
Fie
ld o
n a
xis,
T
K=1
10.7 MeV -photons
Achieved with Al-former(Prototype I)
Achieved with Al-former(Prototype III)
Achieved with iron former(Prototype IV)
Achieved with iron formerand iron yoke (Prototype IV)
Achieved with Prorotype V(iron former and iron yoke)
Aluminium former
Fe former
Fe former & yoke
Prototype 5 @ 250A
@ 200A
Slide 45July 26, 2007 Toward the ILC
CCLRC
Specification for 4m Undulator Module
On axis field 0.86 T
Peak to peak variation <1%
Period 11.5 mm
Nominal Current ~250 A
Nom current as % of Short Sample 80%
SC wire NbTi 0.4mm dia., SC:Cu ratio 0.9:1
Winding Cross Section 7 wires wide x 8 high
Number of magnets per module 2 (powered separately for tests)
Length of magnetic field 2 x 1.74 m
No Beam Collimators or Beam Pipe Vacuum pumping ports in the magnet beam pipe
Slide 46July 26, 2007 Toward the ILC
CCLRC
4m Prototype Module
Stainless steel vacuum vessel with Central turret
Stainless steel vacuum vessel with Central turret
50K Al Alloy Thermal shield. Supported from He bath
Stainless Steel He bath filled with liquid Helium.
Magnet support provided by a stiff U Beam
U beam Support rod
Superconducting Magnet cooled to 4.2K
Beam Tube
Construction has started, will be complete by Autumn 07
Slide 47July 26, 2007 Toward the ILC
CCLRC
Magnet Design Concept
2 start helical groove machined in steel former
2 start helical groove machined in steel former
Cu beam pipe, withconductor wound on to tube OD
Steel Yoke. Provides 10% increase in field and mechanical support for former
PC board for S/C ribbon connections
Winding pins
Steel yoke
Slide 48July 26, 2007 Toward the ILC
Americas
STATUS OF CORNELL UNDULATOR PROTOTYPING
Alexander Mikhailichenko, Maury Tigner
Cornell University, LEPP, Ithaca, NY 14853
A superconducting, helical undulator based source has been selected as the baseline design for the ILC. This report outlines progress towards design, modeling and testing elements of the needed undulator. A magnetic length of approximately 150 m is needed to produce the desired positron beam. This could be composed of about 50 modules of 4 m overall length each.This project is dedicated to the design and eventual fabrication of one full scale, 4 m long undulator module. The concept builds on a copper vacuum chamber of 8 mm internal bore
Slide 49July 26, 2007 Toward the ILC
Americas
Fig.1;Extensible prototype concept for ILC positron undulator . Diameter of cryostat =102mm
Slide 50July 26, 2007 Toward the ILC
Americas
Several 40 cm long undulator models with 10 and 12 mm period, Ø 8 mm clear bore have been made and measured. See Table
OFC vacuum chamber, RF smoothness
For aperture diameter 5.75 mm we expect: for period 8mm – K~0.4 ; for period 10mm -K~0.9
SC wire 54 filaments 56 filaments 56 filaments
# layers 5* 6* 9** (12***) +sectioning
λ=10 mm K=0.36 tested K=0.42 tested K≈0.5 (calculated)
λ=12 mm K=0.72 tested K=0.83 tested K≈1 (calculated)
*) Wire – Ø0.6 mm bare; **) Wire – Ø0.4 mm bare; ***) Wire – Ø0.3 mm bare
Fig.3: Field profile – conical ends. 6 layer, 12 mm period – orthogonal hall probes. 1Tesla full scale
Slide 51July 26, 2007 Toward the ILC
Americas
•Progress to Date
•An overall concept design for the module as shown in Fig. 1 has been developed. The design is very compact, having an outside cryostat diameter of 100 mm. Standard size plumbing components are used throughout. Figure 1 shows the cross section design for tapered end coils.
•We have made optimization studies for undulators having 10 and 12 mm period with 8 mm clear bore and wound with various commercially available wires.
•Technology for fabrication of the undulator has been reduced to practice including winding of the wire and the helical iron yoke as well as procedures and apparatus for measuring the field distribution at the operating temperature. •Several 40 cm long undulator models with 10 and 12 mm period, 8 mm clear bore have been made and measured.
Slide 52July 26, 2007 Toward the ILC
Americas
Capture versus initial rf gradient
Initial rf gradient (MV/m)
Pos
itron
Cap
ture
(ar
b. u
nits
)
Batygin slac-pub-11238
Slide 53July 26, 2007 Toward the ILC
AmericasPrototype Positron Capture Section
Slide 54July 26, 2007 Toward the ILC
AmericasPreliminary Microwave Checking
1300.175 MHz at 20°C, N2
1300.125 MHz at 20°C, N2
Field Plots for Bead Pulling Two Different Frequencies Showing the Correct Cell Frequency and Tuning Property.
Measurement Setup for the Stacked Structure before Brazing without Tuning
Slide 55July 26, 2007 Toward the ILC
Americas
Brazed Coupler and Body Subassemblies - Ready for Final Brazing
Slide 56July 26, 2007 Toward the ILC
AmericasSummary Page for the Capture RF
Juwen Wang
• Vacuum Leak Check• Recheck the RF Properties• Installation:
• Support;• Cooling system;• Waveguide system;• Window; • Vacuum system; • Solenoid; • Monitoring System.
• High Power Test (5MW, 1.2 ms,5 Hz)• Beam Acceleration Test
Slide 57July 26, 2007 Toward the ILC
AmericasOptics
• Source optics laid out. Need to look at details– Beam loss and collimation
– Component interferences (target halls, DR injection)
– Refine and document optics and beam physics
58 EPAC June 2003
E-166 Experiment
E-166 is a demonstration of undulator-based polarized positron production for linear colliders
- E-166 uses the 50 GeV SLAC beam in conjunction with 1 m-long, helical undulator to make polarized photons in the FFTB.- These photons are converted in a ~0.5 rad. len. thick target into polarized positrons (and electrons).- The polarization of the positrons and photons will be measured.
59 EPAC June 2003
Undulator-Based Production of Polarized Undulator-Based Production of Polarized PositronsPositrons
E-166 Collaboration
(45 Collaborators)
60 EPAC June 2003
Undulator-Based Production of Polarized Undulator-Based Production of Polarized PositronsPositronsE-166 Collaborating Institutions
(15 Institutions)
Slide 61July 26, 2007 Toward the ILC
Americas
Slide 62July 26, 2007 Toward the ILC
Americas
Slide 63July 26, 2007 Toward the ILC
AmericasFLUKA Validation Experiment
Slide 64July 26, 2007 Toward the ILC
AmericasFLUKA Validation Experiment
• SLAC/CERN Collaboration (RP groups) – Validation of FLUKA activation calculations
• 100 W
• 30 GeV electron beam in ESA at SLAC
• Cylindrical copper dump
• Samples around the dump (including a Ti-4V-6Al)
• Look mr/hour and gamma spectrum from irradiated samples
– Run at the beginning of April …
Slide 65July 26, 2007 Toward the ILC
AmericasExperiment Setup
Slide 66July 26, 2007 Toward the ILC
AmericasPreliminary Data: Ti and Ti-alloy
Slide 67July 26, 2007 Toward the ILC
Americas
Target Hall / Remote Handling
• Projected ILC running mode– 9 month run + 3 month shutdowns
• Target stations designed with 2 year lifetime– Replace target station every shutdown– If target fails then
• EITHER a “hot” spare• OR fast replacement
• Radiation levels ~ 100 rem/hour immediately after beam shutoff– Remote handling needed
• Target hall deep underground– Vertical target extraction/replacement
• Vinod used to work in the FNAL antiproton source!!
Slide 68July 26, 2007 Toward the ILC
Americas
ILC Target Hall Cartoon (single target)
Slide 69July 26, 2007 Toward the ILC
AmericasTarget Remote Handling
Estimated 53 hour replacement time
July 26, 2007 Toward the ILC 70
M. W
oodward, R
AL
Cryocooler
(if required)
+ vacuum pump
+ water pump
Details of vertical drive for target wheel not yet considered.
Remote-Handling Module and Plug
Module contains target, capture optics and first accelerating cavity.
Slide 71July 26, 2007 Toward the ILC
Americas
TRIUMF – ISAC FACILITY
Slide 72July 26, 2007 Toward the ILC
AmericasVisit to ORNL
Slide 73July 26, 2007 Toward the ILC
AmericasVisit to ORNL
Slide 74July 26, 2007 Toward the ILC
AmericasVisit to ORNL
Slide 75July 26, 2007 Toward the ILC
AmericasVisit to ORNL
• The remote handling systems for the SNS target is estimated to have cost about $100M
• Off the cuff estimate to work up ILC e+ Remote Handling Systems for the EDR would be about 4-5 FTE spread out over 3 years
Americas
Slide 76July 26, 2007 Toward the ILC
ILC Status
Reference Design Report (RDR) completedReference Design Report (RDR) completedDesign feasibility Design feasibility
Alternative technologies (cost saving, risk reduction ..)Alternative technologies (cost saving, risk reduction ..)
R&D prioritiesR&D priorities
4-volume report, Executive Summary, Physics Case, 4-volume report, Executive Summary, Physics Case, Accelerator, Detectors ~ 700 pages producedAccelerator, Detectors ~ 700 pages produced
Printed version in AugustPrinted version in August
Now setting up Engineering Design Phase (EDR)Now setting up Engineering Design Phase (EDR)Define EDR, (nn% design complete?)Define EDR, (nn% design complete?)
Choose final design technologiesChoose final design technologies
Setup structure to get it done (regional balance to optimize Setup structure to get it done (regional balance to optimize use of resources)use of resources)
Three year timescaleThree year timescale
Reference Design Report (RDR) completedReference Design Report (RDR) completedDesign feasibility Design feasibility
Alternative technologies (cost saving, risk reduction ..)Alternative technologies (cost saving, risk reduction ..)
R&D prioritiesR&D priorities
4-volume report, Executive Summary, Physics Case, 4-volume report, Executive Summary, Physics Case, Accelerator, Detectors ~ 700 pages producedAccelerator, Detectors ~ 700 pages produced
Printed version in AugustPrinted version in August
Now setting up Engineering Design Phase (EDR)Now setting up Engineering Design Phase (EDR)Define EDR, (nn% design complete?)Define EDR, (nn% design complete?)
Choose final design technologiesChoose final design technologies
Setup structure to get it done (regional balance to optimize Setup structure to get it done (regional balance to optimize use of resources)use of resources)
Three year timescaleThree year timescale
Slide 77July 26, 2007 Toward the ILC
Americas
What do we want
• RDR to EDR phase– ILC “management” is trying to match ILC tasks to world wide
ILC resources– ILC positron source EDR leadership may well migrate to
Europe– Strong US input is still needed to finish EDR
• Design of all aspects of the ILC e+ Sub-systems needs help– Need people to consult with – Need collaborators to help with design– Need collaborators to take the lead in the design– Need collaborators to do the design
Slide 78July 26, 2007 Toward the ILC
AmericasPolarized Electron Source
(A. Brachmann, SLAC)
Slide 79July 26, 2007 Toward the ILC
Americas
Select Positron References, 1
• ILC RDR Positron Chapter:
http://media.linearcollider.org/report-apr03-part1.pdf sec. 2.3, pg. 45 ff• ILC Positron Source Collaboration Meetings
1st meeting at RAL September, 2006: http://www.te.rl.ac.uk/ILC_Positron_Source_Meeting/ILCMeeting.html
2nd meeting at IHEP, Beijing January, 2007 : http://hirune.kek.jp/mk/ilc/positron/IHEP/• ILC Notes
1. ILC Target Prototype Simulation by Means of FEM Antipov, S; Liu, W; Gai, W [ILC-NOTE-2007-011] http://ilcdoc.linearcollider.org/record/6949
2. On the Effect of Eddy Current Induced Field , Liu, W ; Antipov, S; Gai, W [ILC-NOTE-2007-010] http://ilcdoc.linearcollider.org/record/6948
3. The Undulator Based ILC Positron Source: Production and Capturing Simulation Study – Update,
Liu, W ; Gai, W [ILC-NOTE-2007-009] http://ilcdoc.linearcollider.org/record/6947• Other Notes
1. F.Zhou,Y.Batygin,Y.Nosochkov,J.C.Sheppard,and M.D.Woodley,"Start-to-end beam optics development and multi-particle tracking for the ILC undulator-based positron source", slac-pub-12239, Jan 2007. http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-12239.pdf
2. F.Zhou,Y.Batygin,A.Brachmann,J.Clendenin,R.H.Miller,J.C.Sheppard,and M.D.Woodley,"Start-to-end transport design and multi-particle tracking for the ILC electron source", slac-pub-12240, Jan 2007. http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-12240.pdf
3. A.Mikhailichenko, " Liquid metal target for ILC*."*. Jun 2006. 3pp.Prepared for European Particle Accelerator Conference (EPAC 06), Edinburgh, Scotland, 26-30 Jun 2006.Published in *Edinburgh 2006, EPAC* 816-818
Slide 80July 26, 2007 Toward the ILC
Americas
Select Positron References, 2• Other Notes, cont’d
4. A.A. Mikhailichenko <http://www-spires.slac.stanford.edu/spires/find/wwwhepau/wwwscan?rawcmd=fin+%22Mikhailichenko%2C%20A%2EA%2E%22>, "Test of SC undulator for ILC.",Jun 2006. 3pp. Prepared for European Particle Accelerator Conference (EPAC 06), Edinburgh, Scotland, 26-30 Jun 2006.Published in *Edinburgh 2006, EPAC* 813-815.
5. A.Mikhailichenko, "Issues for the rotating target", CBN-07-02, 2007, http://www.lns.cornell.edu/public/CBN/2007/CBN07-2/CBN07-2.pdf
6. A.Mikhailichenko, "Positron Source for ILC:A perspective", CBN-06-06, 2006, http://www.lns.cornell.edu/public/CBN/2006/CBN06-1/CBN06-1.pdf
7. Preliminary Investigations of Eddy Current Effects on a Spinning Disk, W.T. Piggott, S. Walston, and D. Mayhall. UCRL-TR-224467, Sep. 8, 20068. Positron Source Target Update, W.T. Piggott, UCRL-PRES-227298, Jan. 16, 2007.9. Computer Calculations of Eddy-Current Power Loss in Rotating Titanium Wheels and Rims in
Localized Axial Magnetic Fields. D.J. Mayhall, W. Stein, and J. Gronberg, UCRL-TR-221440, May 17, 2006
10. A Preliminary Low-Frequency Electromagnetic Analysis of a Flux Concentrator, D.J. Mayhall, UCRL-TR-221994, June 13, 2006
Also see Posipol 2007 and Posipol 2006:
http://events.lal.in2p3.fr/conferences/Posipol07/
http://posipol2006.web.cern.ch/Posipol2006/
Recommended