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Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Undulator SpecificationsHeinz-Dieter Nuhn, SLAC / SSRL
November 14, 2003
Undulator SpecificationsHeinz-Dieter Nuhn, SLAC / SSRL
November 14, 2003
Undulator OverviewUndulator Overview FEL Performance AssessmentFEL Performance Assessment Recent Undulator Parameter ChangesRecent Undulator Parameter Changes
Undulator OverviewUndulator Overview FEL Performance AssessmentFEL Performance Assessment Recent Undulator Parameter ChangesRecent Undulator Parameter Changes
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Linac Coherent Light Source
Near Hall
Far Hall
Undulator
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
UNDULATOR
3,410 406
11,905 mm
Horizontal Steering Coil
Vertical Steering Coil
Beam Position Monitor
863 mm
X-Ray Diagnostics
Quadrupoles
LCLS Undulator Schematic (Regular Section)LCLS Undulator Schematic (Regular Section)LCLS Undulator Schematic (Regular Section)LCLS Undulator Schematic (Regular Section)
130,092 mmTotal Length
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
SASE FEL theory well developedSASE FEL theory well developed
and verified by simulationsand verified by simulations
FEL radiation starts from noise in FEL radiation starts from noise in spontaneous radiation spontaneous radiation
Transverse radiation electric Transverse radiation electric field modulates the energy and field modulates the energy and bunches the electrons within an bunches the electrons within an optical wavelengthoptical wavelength
Exponential build-up of radiation Exponential build-up of radiation along undulator lengthalong undulator length
SASE FELsSASE FELs
Undulator RegimeUndulator Regime
Exponential Gain Regime
Exponential Gain Regime
Saturation
Saturation
1 % of X-Ray Pulse1 % of X-Ray Pulse
Electron BunchMicro-Bunching
Electron BunchMicro-Bunching
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Expected PerformanceExpected Performance
Low charge cases are modeled in PARMELALow charge cases are modeled in PARMELAafter the GTF results and then imported into after the GTF results and then imported into ELEGANT/GENESIS for the transportELEGANT/GENESIS for the transportthrough the LCLS beam line. through the LCLS beam line.
The simulations includes:The simulations includes:
Space charge in the gunSpace charge in the gun
Emittance compensationEmittance compensation
Wakefield and CSR effects Wakefield and CSR effects
Optimized beam transport (Jitter)Optimized beam transport (Jitter)
Spontaneous Undulator Radiation Spontaneous Undulator Radiation
Low charge cases are modeled in PARMELALow charge cases are modeled in PARMELAafter the GTF results and then imported into after the GTF results and then imported into ELEGANT/GENESIS for the transportELEGANT/GENESIS for the transportthrough the LCLS beam line. through the LCLS beam line.
The simulations includes:The simulations includes:
Space charge in the gunSpace charge in the gun
Emittance compensationEmittance compensation
Wakefield and CSR effects Wakefield and CSR effects
Optimized beam transport (Jitter)Optimized beam transport (Jitter)
Spontaneous Undulator Radiation Spontaneous Undulator Radiation
All cases reach saturationAll cases reach saturation
ParmelaParmelaParmelaParmela ElegantElegantElegantElegant Genesis / GingerGenesis / GingerGenesis / GingerGenesis / Ginger
space-chargespace-charge compression, wakes, CSR, …compression, wakes, CSR, … SASE FEL with wakesSASE FEL with wakes
Start-To-End Simulations:Start-To-End Simulations:
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Workshop on Start-To-End SimulationsWorkshop on Start-To-End Simulations
Beam Dynamics Mini WorkshopFuture Light Sources
Start-To-End Simulations for SASE FELs (S2E 2003)Chaired by
John Galayda (SLAC) and Joerg Rossbach (DESY)
Dates
August 18 – 22, 2003
Location
DESY-Zeuthen, Berlin, Germany
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Comparison of GINGER/GENESIS resultsfor 1-nC LCLS “0-order” Case
Comparison of GINGER/GENESIS resultsfor 1-nC LCLS “0-order” Case
Observations:• GENESIS shows very slightly longer gain
length, later saturation but higher power• GINGER shows stronger post-saturation
power oscillation (more deeply trapped particles?)
• Method for choosing best K was slightly different for both codes
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
GINGER/GENESIS results for “0-order” 200-pC case
GINGER/GENESIS results for “0-order” 200-pC case
Observations:• Again, GENESIS shows slightly longer
gain length, 10-m later saturation but 15% higher power
• Again, GINGER shows deeper post-saturation power oscillation
• Little sensitivity (2 m, 7%) in GINGER results to 8X particle number increase
• Possible reasons for differences: bugs slight differences in initial e-beam
properties (e.g. mismatch) grid effects (e.g. outer boundary)???
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
1-nC LCLS: “1st-order” envelope reconstruction: max P(z) vs. slice time1-nC LCLS: “1st-order” envelope reconstruction: max P(z) vs. slice time
100 GW100 GW
Some quick observations:• Power suppressed in regions with high energy spread [-90:-70 fs]• GENESIS shows ~2-3X greater power than GINGER for no-wake
cases• For runs including wake fields, GINGER shows somewhat more peak
power for the main body (but more localized in time)• Beam centroid wander may be important – better modeled by
GENESIS
GINGER GENESIS
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Tolerance Analysis: Tolerance Analysis: RONRONR. Dejus, N. VinokurovR. Dejus, N. VinokurovTolerance Analysis: Tolerance Analysis: RONRONR. Dejus, N. VinokurovR. Dejus, N. Vinokurov
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Undulator Performance Requirements (as of May 2003)Undulator Performance Requirements (as of May 2003)
ParameterParameter SymbolSymbol TargetTarget
(Nom.)(Nom.)UnitsUnits ToleranceTolerance
((criticalcritical))
Effective Undulator ParameterEffective Undulator Parameter KK 3.7113.711 ±0.015 ±0.015 %%
Average Gap HeightAverage Gap Height gg 6.06.0 mmmm +0.006+0.006
Average Period LengthAverage Period Length uu 30.0030.00 mmmm ±0.03±0.03
Wiggle PlaneWiggle Plane horizontalhorizontal ——
RMS Trajectory Straightness ToleranceRMS Trajectory Straightness Tolerance xx 22 mm ——
RMS Segment Phase Shake ToleranceRMS Segment Phase Shake Tolerance 1010 degreesdegrees ——
3.6350 3.6350 6.56.5
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Trajectory Straightness RequirementTrajectory Straightness RequirementTrajectory Straightness RequirementTrajectory Straightness Requirement
Preserve transverse overlap between beam and Preserve transverse overlap between beam and radiationradiation => Tolerance for betatron amplitude < 8 => Tolerance for betatron amplitude < 8 m (beam radius m (beam radius
dep.)dep.)
Avoid longitudinal phase shake between beam and Avoid longitudinal phase shake between beam and radiationradiation
=> Tolerance for rms phase shake 10 degrees per module=> Tolerance for rms phase shake 10 degrees per module
=> Equivalent tolerance for rms electron beam straightness 2 => Equivalent tolerance for rms electron beam straightness 2 m m
Preserve transverse overlap between beam and Preserve transverse overlap between beam and radiationradiation => Tolerance for betatron amplitude < 8 => Tolerance for betatron amplitude < 8 m (beam radius m (beam radius
dep.)dep.)
Avoid longitudinal phase shake between beam and Avoid longitudinal phase shake between beam and radiationradiation
=> Tolerance for rms phase shake 10 degrees per module=> Tolerance for rms phase shake 10 degrees per module
=> Equivalent tolerance for rms electron beam straightness 2 => Equivalent tolerance for rms electron beam straightness 2 m m
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Workshop on Undulator ParametersWorkshop on Undulator Parameters
LCLS Undulator Parameter WorkshopChaired by
Heinz-Dieter Nuhn (SLAC)
Dates
November 24, 2003
Location
APS, Argonne, USA
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Workshop FocusWorkshop FocusWorkshop FocusWorkshop Focus
Set Undulator PeriodSet Undulator Period
Reduction of maximum available linac energyReduction of maximum available linac energy
Undulator gap height increaseUndulator gap height increase
Longer break distancesLonger break distances
Weaker FODO latticeWeaker FODO lattice
Set Undulator PeriodSet Undulator Period
Reduction of maximum available linac energyReduction of maximum available linac energy
Undulator gap height increaseUndulator gap height increase
Longer break distancesLonger break distances
Weaker FODO latticeWeaker FODO lattice
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Halbach formula for hybrid undulator is used to Halbach formula for hybrid undulator is used to estimate relation between gap/period and on-axis estimate relation between gap/period and on-axis fieldfield
Measured prototype field 5.3% larger than estimatedMeasured prototype field 5.3% larger than estimated
Halbach formula for hybrid undulator is used to Halbach formula for hybrid undulator is used to estimate relation between gap/period and on-axis estimate relation between gap/period and on-axis fieldfield
Measured prototype field 5.3% larger than estimatedMeasured prototype field 5.3% larger than estimated
Adjusting Estimate of On-Axis Undulator FieldAdjusting Estimate of On-Axis Undulator FieldAdjusting Estimate of On-Axis Undulator FieldAdjusting Estimate of On-Axis Undulator Field
2gap gap
b cperiod periodB a e
3.44 T
5.08
1.54
a
b
c
3 cm1.325 T
6.00 mm
periodB
gap
6.35
3 cm1.325 T
mm
periodB
gap
5.08
1.5
3.6
4
2 Ta
b
c
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Undulator PeriodUndulator PeriodUndulator PeriodUndulator Period
Present undulator period length of 3 cm is near Present undulator period length of 3 cm is near optimum for shortest gain lengthoptimum for shortest gain length
Change of undulator period length would require more Change of undulator period length would require more man-power and time than available before next reviewman-power and time than available before next review
Undulator period length will be kept at Undulator period length will be kept at
uu = 3.0 cm = 3.0 cm
Present undulator period length of 3 cm is near Present undulator period length of 3 cm is near optimum for shortest gain lengthoptimum for shortest gain length
Change of undulator period length would require more Change of undulator period length would require more man-power and time than available before next reviewman-power and time than available before next review
Undulator period length will be kept at Undulator period length will be kept at
uu = 3.0 cm = 3.0 cm
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Maximum Available Linac EnergyMaximum Available Linac EnergyMaximum Available Linac EnergyMaximum Available Linac Energy
14.35 GeV has been nominal energy to reach 1.5 Å14.35 GeV has been nominal energy to reach 1.5 Å
Loss of available linac energy due toLoss of available linac energy due to Reduction of available linac sections (incl. Injector Reduction of available linac sections (incl. Injector
relocation)relocation)
Off-crest accelerationOff-crest acceleration
New maximum energy set to 14.1 GeV to restore New maximum energy set to 14.1 GeV to restore operational overheadoperational overhead
Requires change in K valueRequires change in K value
14.35 GeV has been nominal energy to reach 1.5 Å14.35 GeV has been nominal energy to reach 1.5 Å
Loss of available linac energy due toLoss of available linac energy due to Reduction of available linac sections (incl. Injector Reduction of available linac sections (incl. Injector
relocation)relocation)
Off-crest accelerationOff-crest acceleration
New maximum energy set to 14.1 GeV to restore New maximum energy set to 14.1 GeV to restore operational overheadoperational overhead
Requires change in K valueRequires change in K value
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Undulator Gap SelectionUndulator Gap SelectionUndulator Gap SelectionUndulator Gap Selection
Undulator gap height changes still possibleUndulator gap height changes still possible
Present gap height: 6 mmPresent gap height: 6 mm
Gap height corrected for measured field: 6.35 mmGap height corrected for measured field: 6.35 mm
Parameter correction for reduced maximum energyParameter correction for reduced maximum energy
Larger gap gives access to short wavelength 1.0 ÅLarger gap gives access to short wavelength 1.0 Å
Undulator gap height changes still possibleUndulator gap height changes still possible
Present gap height: 6 mmPresent gap height: 6 mm
Gap height corrected for measured field: 6.35 mmGap height corrected for measured field: 6.35 mm
Parameter correction for reduced maximum energyParameter correction for reduced maximum energy
Larger gap gives access to short wavelength 1.0 ÅLarger gap gives access to short wavelength 1.0 Å
max
6.5 mm
1.298 T
3.6350
gap
B
K
14.09 GeV 1.5 Å
4.46 GeV 15.0 År
r
E
E
max
8.2 mm
1.013 T
2.838
gap
B
K
14.03 GeV 1.0 Å
11.46 GeV 1.5 Å
3.62 GeV 15.0 Å
r
r
r
E
E
E
New ParametersNew ParametersNew ParametersNew Parameters
Rejected
Rejected
Rejected
Rejected
More Room for Vacuum Chamber
More Room for Vacuum Chamber
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
LCLS Undulator Large Gap / Low K ProposalLCLS Undulator Large Gap / Low K Proposal
Proposed Proposed Undulator Undulator
LengthLength
Emittance Emittance GoalGoal
Safety Safety OverheadOverhead
Emittance Emittance AchievedAchieved
Based on Based on Chosen Chosen
ParametersParameters
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
New Break LengthsNew Break LengthsNew Break LengthsNew Break Lengths
Separations between undulator modules (breaks) designed to Separations between undulator modules (breaks) designed to produce slippage by integer number of optical wavelength.produce slippage by integer number of optical wavelength.
Break increments for adding slippage of 1 optical wavelength is Break increments for adding slippage of 1 optical wavelength is LLBB==uu (1+K (1+K22/2). /2).
LLBB=23.7 cm (old); 22.8 cm (new)=23.7 cm (old); 22.8 cm (new) Present design uses break pattern 1-1-2 which corresponds to Present design uses break pattern 1-1-2 which corresponds to
the lengths sequence the lengths sequence 18.7 cm – 18.7 cm – 42.1 cm 18.7 cm – 18.7 cm – 42.1 cm
18.7 cm gives not enough space for quads, BPMs, etc.18.7 cm gives not enough space for quads, BPMs, etc. Length needed > 30 cm Length needed > 30 cm 42.1 cm gives not enough space for x-ray diagnostics42.1 cm gives not enough space for x-ray diagnostics Length needed > 70 cm Length needed > 70 cm
New break pattern 2-2-4 corresponding to lengthNew break pattern 2-2-4 corresponding to lengthsequence 40.6 cm – 40.6 cm – 86.3 cmsequence 40.6 cm – 40.6 cm – 86.3 cm
Separations between undulator modules (breaks) designed to Separations between undulator modules (breaks) designed to produce slippage by integer number of optical wavelength.produce slippage by integer number of optical wavelength.
Break increments for adding slippage of 1 optical wavelength is Break increments for adding slippage of 1 optical wavelength is LLBB==uu (1+K (1+K22/2). /2).
LLBB=23.7 cm (old); 22.8 cm (new)=23.7 cm (old); 22.8 cm (new) Present design uses break pattern 1-1-2 which corresponds to Present design uses break pattern 1-1-2 which corresponds to
the lengths sequence the lengths sequence 18.7 cm – 18.7 cm – 42.1 cm 18.7 cm – 18.7 cm – 42.1 cm
18.7 cm gives not enough space for quads, BPMs, etc.18.7 cm gives not enough space for quads, BPMs, etc. Length needed > 30 cm Length needed > 30 cm 42.1 cm gives not enough space for x-ray diagnostics42.1 cm gives not enough space for x-ray diagnostics Length needed > 70 cm Length needed > 70 cm
New break pattern 2-2-4 corresponding to lengthNew break pattern 2-2-4 corresponding to lengthsequence 40.6 cm – 40.6 cm – 86.3 cmsequence 40.6 cm – 40.6 cm – 86.3 cm
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Weaker FODO LatticeWeaker FODO LatticeWeaker FODO LatticeWeaker FODO Lattice
FODO Lattice had been designed for FODO Lattice had been designed for < <x,yx,y>=18 m at 1.5 Å >=18 m at 1.5 Å
Required gradient of 106-107 T/m for 5 cm long quadsRequired gradient of 106-107 T/m for 5 cm long quads
New gradient set to 60 T/m toNew gradient set to 60 T/m to Increase Saturation PowerIncrease Saturation Power
Relax Beam-Based Alignment TolerancesRelax Beam-Based Alignment Tolerances
Saturation length only slightly increasedSaturation length only slightly increased
Average beta function at 1.5 Å is nowAverage beta function at 1.5 Å is now < <x,yx,y>=30 m>=30 m
Focusing and defocusing magnets will be identicalFocusing and defocusing magnets will be identical
FODO Lattice had been designed for FODO Lattice had been designed for < <x,yx,y>=18 m at 1.5 Å >=18 m at 1.5 Å
Required gradient of 106-107 T/m for 5 cm long quadsRequired gradient of 106-107 T/m for 5 cm long quads
New gradient set to 60 T/m toNew gradient set to 60 T/m to Increase Saturation PowerIncrease Saturation Power
Relax Beam-Based Alignment TolerancesRelax Beam-Based Alignment Tolerances
Saturation length only slightly increasedSaturation length only slightly increased
Average beta function at 1.5 Å is nowAverage beta function at 1.5 Å is now < <x,yx,y>=30 m>=30 m
Focusing and defocusing magnets will be identicalFocusing and defocusing magnets will be identical
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
LCLS Optimum -Function at Short Wavelength LCLS Optimum -Function at Short Wavelength
Optimum Beta-FunctionOptimum Beta-Function
New Beta-FunctionNew Beta-Function
14.1 GeV 14.1 GeV
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
LCLS Operating Points for 1 nC Bunch Charge (Old)LCLS Operating Points for 1 nC Bunch Charge (Old)
LCLS Operating Point at LCLS Operating Point at 1.5 Å1.5 ÅLCLS Operating Point at LCLS Operating Point at 1.5 Å1.5 Å LCLS Operating Point at LCLS Operating Point at 15 Å15 ÅLCLS Operating Point at LCLS Operating Point at 15 Å15 Å
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
LCLS Operating Points for 1 nC Bunch Charge (New)LCLS Operating Points for 1 nC Bunch Charge (New)
LCLS Operating Point at LCLS Operating Point at 1.5 Å1.5 ÅLCLS Operating Point at LCLS Operating Point at 1.5 Å1.5 Å
Operating PointOperating Point Operating PointOperating Point
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
LCLS Operating Points for 1 nC Bunch Charge (New)LCLS Operating Points for 1 nC Bunch Charge (New)
LCLS Operating Point at LCLS Operating Point at 15 Å15 ÅLCLS Operating Point at LCLS Operating Point at 15 Å15 Å
Operating PointOperating PointOperating PointOperating Point
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Beam Based Alignment Tolerances (Paul Emma)Beam Based Alignment Tolerances (Paul Emma)
0.040.04
00 44
100100
100100
22
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
OLD NEWUndulator Type planar hybrid planar hybridMagnet Material NdFeB NdFeBWiggle Plane horizontal horizontalGap 6 6.5
mmPeriod Length 3.0 3.0 cmPeak On-Axis Field 1.325 1.298 TK 3.711 2.635
Module Length 3.41 3.41 mNumber of Modules 33 33Undulator Magnet Length 112.5 112.5 m
Break Length 18.7-18.7-42.1 40.6-40.6-86.3 cmTotal Device Length 121.8 130.2 m
OLD NEWUndulator Type planar hybrid planar hybridMagnet Material NdFeB NdFeBWiggle Plane horizontal horizontalGap 6 6.5
mmPeriod Length 3.0 3.0 cmPeak On-Axis Field 1.325 1.298 TK 3.711 2.635
Module Length 3.41 3.41 mNumber of Modules 33 33Undulator Magnet Length 112.5 112.5 m
Break Length 18.7-18.7-42.1 40.6-40.6-86.3 cmTotal Device Length 121.8 130.2 m
Summary of Nominal Undulator Design ChangesSummary of Nominal Undulator Design Changes
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
OLD NEW
Lattice Type FODO FODOMagnet Type permanent permanentNominal Magnet Length 5 5 cmQF Gradient 107 60 T/mQD Gradient -106 -60 T/mAverage Function at 1.5 Å 18.0 30 mLowest Usable Energy 3.17 1.84 GeV
OLD NEW
Lattice Type FODO FODOMagnet Type permanent permanentNominal Magnet Length 5 5 cmQF Gradient 107 60 T/mQD Gradient -106 -60 T/mAverage Function at 1.5 Å 18.0 30 mLowest Usable Energy 3.17 1.84 GeV
Summary of Nominal Focusing Lattice ChangesSummary of Nominal Focusing Lattice Changes
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Summary of Electron Beam ParametersSummary of Electron Beam Parameters
At 15 Å OLD NEW
Electron Beam Energy 4.45 4.46 GeV 8880 8722<> 7.3 8.9
mrms beam radius 35 34 m
At 15 Å OLD NEW
Electron Beam Energy 4.45 4.46 GeV 8880 8722<> 7.3 8.9
mrms beam radius 35 34 m
At 1.5 Å OLD NEW
Electron Beam Energy 14.35 14.09 GeV 28082 27580<> 18.0 30.0
mrms beam radius 36 35 m
At 1.5 Å OLD NEW
Electron Beam Energy 14.35 14.09 GeV 28082 27580<> 18.0 30.0
mrms beam radius 36 35 m
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
ConclusionsConclusions
Requirements for LCLS undulator are well establishedRequirements for LCLS undulator are well establishedLCLS undulator performance requirements are well understoodLCLS undulator performance requirements are well understoodRisks have been assessed and undulator specifications address the riskRisks have been assessed and undulator specifications address the riskNew parameter values have been chosenNew parameter values have been chosen
Increase in undulator gap, Increase in undulator gap, reduction in maximum electron beam energy, reduction in maximum electron beam energy, longer break length, and longer break length, and reduced quadrupole gradientsreduced quadrupole gradients
Benefits areBenefits aremore room for vacuum chambermore room for vacuum chambermore energy safety marginmore energy safety marginmore space for diagnostics components between undulator modulesmore space for diagnostics components between undulator modulesincrease of accessible wavelength rangeincrease of accessible wavelength range
Requirements for LCLS undulator are well establishedRequirements for LCLS undulator are well establishedLCLS undulator performance requirements are well understoodLCLS undulator performance requirements are well understoodRisks have been assessed and undulator specifications address the riskRisks have been assessed and undulator specifications address the riskNew parameter values have been chosenNew parameter values have been chosen
Increase in undulator gap, Increase in undulator gap, reduction in maximum electron beam energy, reduction in maximum electron beam energy, longer break length, and longer break length, and reduced quadrupole gradientsreduced quadrupole gradients
Benefits areBenefits aremore room for vacuum chambermore room for vacuum chambermore energy safety marginmore energy safety marginmore space for diagnostics components between undulator modulesmore space for diagnostics components between undulator modulesincrease of accessible wavelength rangeincrease of accessible wavelength range
Undulator Parameter Workshop, November 14, 2003Undulator Parameter Workshop, November 14, 2003 Heinz-Dieter Nuhn, SLAC / SSRLHeinz-Dieter Nuhn, SLAC / SSRL
Undulator SpecificationsUndulator Specifications [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
End of Presentation