LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Introduction to the LCLS UndulatorsHeinz-Dieter Nuhn, SLAC / LCLS
October 14, 2004
Introduction to the LCLS UndulatorsHeinz-Dieter Nuhn, SLAC / LCLS
October 14, 2004
Undulator Overview Requirement Documents Undulator Fields and Tapering Cradle Components and Motion MMF Physics Requirements
Undulator Overview Requirement Documents Undulator Fields and Tapering Cradle Components and Motion MMF Physics Requirements
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Linac Coherent Light Source
Near Hall
Far Hall
Undulator
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Undulator Segment Prototype
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Undulator Requirement Documents
Index URL: http://www-ssrl.slac.stanford.edu/lcls/requirements.html
Index URL: http://www-ssrl.slac.stanford.edu/lcls/requirements.html
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Undulator Type planar hybridMagnet Material NdFeBWiggle Plane horizontalGap 6.8 mmPeriod Length 30.0 ± 0.05 mmEffective On-Axis Field 1.249 TStandard Effective K 3.49290 ± 0.015%Range of Effective Undulator Parameter K 3.5000 - 3.4929 (3.4804)Accumulated Segment Phase Error Tolerance 10 degrees
(at any point along segment)
Module Length 3.40 mNumber of Modules 33Undulator Magnet Length 112.2 m
Standard Break Lengths 48.2 - 48.2 - 94.9 cmNominal Total Device Length 130.954 m
Quadrupole Magnet Technology EMQNominal Quadrupole Magnet Length 7 cmIntegrated Quadrupole Gradient 3.0 T
Undulator Type planar hybridMagnet Material NdFeBWiggle Plane horizontalGap 6.8 mmPeriod Length 30.0 ± 0.05 mmEffective On-Axis Field 1.249 TStandard Effective K 3.49290 ± 0.015%Range of Effective Undulator Parameter K 3.5000 - 3.4929 (3.4804)Accumulated Segment Phase Error Tolerance 10 degrees
(at any point along segment)
Module Length 3.40 mNumber of Modules 33Undulator Magnet Length 112.2 m
Standard Break Lengths 48.2 - 48.2 - 94.9 cmNominal Total Device Length 130.954 m
Quadrupole Magnet Technology EMQNominal Quadrupole Magnet Length 7 cmIntegrated Quadrupole Gradient 3.0 T
Summary of Nominal Undulator Parameters
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Micro Tapering V: K valuesMicro Tapering V: K values
The following list contains the nominal K values for the 33 undulator segments for the 6.8 mm gap height:
The following list contains the nominal K values for the 33 undulator segments for the 6.8 mm gap height:
This amount of tapering requires only a negligible adjustment for break lengths.
After achieving goal performance, tapering beyond saturation point is desirable. (up to 0.56% total)
This amount of tapering requires only a negligible adjustment for break lengths.
After achieving goal performance, tapering beyond saturation point is desirable. (up to 0.56% total)
Undulator Segment Keff
1 3.50002 3.49983 3.49964 3.49935 3.49916 3.49897 3.49878 3.49849 3.498210 3.498011 3.497812 3.497613 3.497314 3.497115 3.496916 3.496717 3.496418 3.496219 3.496020 3.495821 3.495522 3.495323 3.495124 3.494925 3.494726 3.494427 3.494228 3.494029 3.493830 3.493531 3.493332 3.493133 3.4929
To compensate energy loss from spontaneous radiationTo compensate energy loss from spontaneous radiation
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Undulator Pole Canting
• Canting comes from wedged spacers
• 4.5 mrad cant angle• Gap can be adjusted by lateral
displacement of wedges• 1 mm shift means 4.5 microns in
gap, or 8.2 Gauss • Beff adjusted to desired value
Source: Liz MoogSource: Liz Moog
Suggested by J. Pflueger, DESYSuggested by J. Pflueger, DESY
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Canting the poles helps in many ways
Facilitates final setting of Beff
Remote control of position allows run-time adjustment
Allows compensating for temperature effect on field strength: ±1.0°C temperature error would require ±1.2 mm lateral shift of undulator
Source Liz MoogSource Liz Moog
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Effective B field vs. x
Measured slope of 6.6 Gauss/mm agrees with calculations(~ 5.7 Gauss/mm for 3 mrad cant)
Field variation allowance between segments is B/B = 1.5x10-4, or B = 2 Gauss, which translates to x = 0.3 mm ( or 1 micron in gap)
Source Liz MoogSource Liz Moog
See I. Vasserman’s Talk for Prototype Measurements
See I. Vasserman’s Talk for Prototype Measurements
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Using Undulator Roll-Away and K Adjustment Function
Neutral; K=3.4965; x=+0.0 mm First; K=3.5000; x=-1.5 mm
Last; K=3.4929; x=+1.5 mm RollAway; K=0.0000; x=+100 mm
PowerTp; K=3.4804; x=+7.0 mm
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Cradle Components
Cradle Components includeUndulator strongback arrangement mounted on horizontal slides
Vacuum chamber support
BPM
Quadrupole
WPM sensors
HLS sensors
(diagnostics chamber)
The undulator strongback arrangement (segment) is mountable on and removable from the cradle with the vacuum chamber in place and without compromising the alignment of the vacuum chamber.
Undulator strongback can be taken off the cradle for magnetic measurements
Complete cradle assembly will be aligned on Coordinate Measurement Machine (CMM).
Cradle Components includeUndulator strongback arrangement mounted on horizontal slides
Vacuum chamber support
BPM
Quadrupole
WPM sensors
HLS sensors
(diagnostics chamber)
The undulator strongback arrangement (segment) is mountable on and removable from the cradle with the vacuum chamber in place and without compromising the alignment of the vacuum chamber.
Undulator strongback can be taken off the cradle for magnetic measurements
Complete cradle assembly will be aligned on Coordinate Measurement Machine (CMM).
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Motions of the Cradle and of Cradle Components
Remotely Controlled Motion:
Cradle: x, y, rollx, y motion of cradle ends are coupledroll motion capability is to be used to keep roll constant
Undulator: xHorizontal slide stages move undulator strongback independent of cradle and vacuum chamber
Manual Adjustment:Cradle Movers to fixed support girder (AMP)Quadrupole and BPM position to cradle.
Remotely Controlled Motion:
Cradle: x, y, rollx, y motion of cradle ends are coupledroll motion capability is to be used to keep roll constant
Undulator: xHorizontal slide stages move undulator strongback independent of cradle and vacuum chamber
Manual Adjustment:Cradle Movers to fixed support girder (AMP)Quadrupole and BPM position to cradle.
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
MMF Physics Requirements
Earth Magnetic Field CompensationEstablish environmental magnet field in MMF to be equal to the environmental field at target location in undulator hall to better than 0.01 T.
MMF TemperatureAverage ambient MMF temperature needs be 20.0 ± 0.1 oC to match the ambient undulator hall temperature of 20.0 ± 0.2 oC.
Magnetic Undulator Shimming toReduce phase error below 10 degrees at 0.15 nm.Reduce 1st Field Integral below ±40×10-6 TmReduce 2nd Field Integral below ±50×10-6 Tm2
Definition of Standard Undulator Axis (SUSA) so thatSUSA is Parallel to Undulator Center LineEffective K along SUSA is 3.4965 ± 0.0005
Alignment of Quadrupole on Cradle with respect to CA*.Tolerance: 40 m (rms).
Routine Operational Checking of Undulator SegmentsRemove 3 segments / month from undulator hall and replace with sparesCharacterize magnetic field of removed segments and prepare for re-installation.
Earth Magnetic Field CompensationEstablish environmental magnet field in MMF to be equal to the environmental field at target location in undulator hall to better than 0.01 T.
MMF TemperatureAverage ambient MMF temperature needs be 20.0 ± 0.1 oC to match the ambient undulator hall temperature of 20.0 ± 0.2 oC.
Magnetic Undulator Shimming toReduce phase error below 10 degrees at 0.15 nm.Reduce 1st Field Integral below ±40×10-6 TmReduce 2nd Field Integral below ±50×10-6 Tm2
Definition of Standard Undulator Axis (SUSA) so thatSUSA is Parallel to Undulator Center LineEffective K along SUSA is 3.4965 ± 0.0005
Alignment of Quadrupole on Cradle with respect to CA*.Tolerance: 40 m (rms).
Routine Operational Checking of Undulator SegmentsRemove 3 segments / month from undulator hall and replace with sparesCharacterize magnetic field of removed segments and prepare for re-installation.
*Cradle Axis (CA) is identical to SUSA when undulator segment is
in neutral horizontal position
*Cradle Axis (CA) is identical to SUSA when undulator segment is
in neutral horizontal position
See J. Welch’s and I Vasserman’s talks for details
See J. Welch’s and I Vasserman’s talks for details
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
Requirements and Specifications are available from the LCLS WEB site.
The main Physics Requirements Document (PRD) outlining the requirements for the undulator system is PRD1.4-001. The MMF specifications are found in PRD1.4-002.
Main Physics Task to be done at the MMF areUndulator magnetic field tuning to specifications under same surrounding magnetic field and temperature conditions as at target location in undulator hall.
Quadrupole and BPM alignment on cradle with respect to undulator strongback
Characterization of undulators that have been used in operation
All undulator segments will be tuned identically.
Micro-tapering implies that every undulator core be at a slightly different K value, which will be accomplished by horizontal positioning.
Requirements and Specifications are available from the LCLS WEB site.
The main Physics Requirements Document (PRD) outlining the requirements for the undulator system is PRD1.4-001. The MMF specifications are found in PRD1.4-002.
Main Physics Task to be done at the MMF areUndulator magnetic field tuning to specifications under same surrounding magnetic field and temperature conditions as at target location in undulator hall.
Quadrupole and BPM alignment on cradle with respect to undulator strongback
Characterization of undulators that have been used in operation
All undulator segments will be tuned identically.
Micro-tapering implies that every undulator core be at a slightly different K value, which will be accomplished by horizontal positioning.
Conclusions
http://ssrl.slac.stanford.edu/lcls/internals/requirements.htmlhttp://ssrl.slac.stanford.edu/lcls/internals/requirements.html
LCLS Undulators October 14, 2004 Heinz-Dieter Nuhn, SLAC / SSRLMMF Review [email protected]@slac.stanford.edu
End of Presentation
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