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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
BBA Related IssuesHeinz-Dieter Nuhn, SLAC / LCLS
June 28, 2004
BBA Related IssuesHeinz-Dieter Nuhn, SLAC / LCLS
June 28, 2004
TechniqueTechnique
SimulationsSimulations
Earth Field ConsiderationsEarth Field Considerations
TechniqueTechnique
SimulationsSimulations
Earth Field ConsiderationsEarth Field Considerations LCLSLCLS
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Basic StrategyBasic Strategy
Save BPM readings as a function of large, deliberate changes in Save BPM readings as a function of large, deliberate changes in ee energy (e.g., 14, 7, and 5 GeV) energy (e.g., 14, 7, and 5 GeV)
Save BPM readings as a function of large, deliberate changes in Save BPM readings as a function of large, deliberate changes in ee energy (e.g., 14, 7, and 5 GeV) energy (e.g., 14, 7, and 5 GeV)
LCLSLCLS
Calculate and correct quad & BPM misalignments and adjust ‘launch’
Repeat ~3 times with first application
Re-apply one iteration per ~1 month (?)
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
The MethodThe Method
BPM readings, BPM readings, mmii, written as sum of upstream kicks , written as sum of upstream kicks ++ offset, offset, bbii
Kicks are sensitive to momentum, Kicks are sensitive to momentum, ppkk, while offsets, , while offsets, bbii, are not, are not
Reference line defined by incoming Reference line defined by incoming xx00, , xx00 launch conditions launch conditions
BPM readings, BPM readings, mmii, written as sum of upstream kicks , written as sum of upstream kicks ++ offset, offset, bbii
Kicks are sensitive to momentum, Kicks are sensitive to momentum, ppkk, while offsets, , while offsets, bbii, are not, are not
Reference line defined by incoming Reference line defined by incoming xx00, , xx00 launch conditions launch conditions
ss
bbii > 0 > 0
EE = 0 = 0
EE < 0 < 0quad offsets and/or pole errorsquad offsets and/or pole errors
iithth BPM BPM jj
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Extrapolation to infinite momentum give BPM offsetsExtrapolation to infinite momentum give BPM offsetsExtrapolation to infinite momentum give BPM offsetsExtrapolation to infinite momentum give BPM offsets
The MethodThe Method
1/1/pp
mmii
offset = bi
(15 GeV/c)(15 GeV/c)11 (10 GeV/c)(10 GeV/c)11 (5 GeV/c)(5 GeV/c)11pp
linear only if linear only if CCijij independent of independent of pp
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
The MethodThe Method
Define…Define…
then solve the linear system…then solve the linear system…
Define…Define…
then solve the linear system…then solve the linear system…
BPM BPM readings readings at at pp11
BPM BPM readings readings at at pp22
BPM BPM offsetsoffsets
quad quad offsetsoffsets
known optical functions at each known optical functions at each ppkk
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
ConstraintsConstraints
Solve with ‘soft-constraints’Solve with ‘soft-constraints’** on resulting BPM and quad offsets on resulting BPM and quad offsetsSolve with ‘soft-constraints’Solve with ‘soft-constraints’** on resulting BPM and quad offsets on resulting BPM and quad offsets
* C. Adolphsen, 1989 PAC* C. Adolphsen, 1989 PAC
~1 mm~1 mm
Without this ‘reasonability’ weighting, resulting BPM and quad offsets can stray out to large values at low frequencies
Scanning beam energy gives sensitivity to (and ~correction of) Scanning beam energy gives sensitivity to (and ~correction of) all field errors, including undulator poles, Earth’s field, etc…all field errors, including undulator poles, Earth’s field, etc…
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Schematic layoutSchematic layout
~300 ~300 mm
UNDULATORUNDULATOR(120 m)(120 m)
LTULTUbest final trajectorybest final trajectory
steering elementssteering elements
xx00xx00
original incoming original incoming launch errorlaunch error
Undulator misaligned w.r.t. linac axis with uncorrelated Undulator misaligned w.r.t. linac axis with uncorrelated and correlatedand correlated** (‘random walk’) component (‘random walk’) component
permanent magnet quadrupoles permanent magnet quadrupoles and undulator polesand undulator poles
* suggested by C. Adolphsen* suggested by C. Adolphsen
BPMsBPMsquadsquads
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Beam-based alignment stepsBeam-based alignment steps
×3×3
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Input Errors Used for SimulationInput Errors Used for Simulation
0.040.04
44
100100
100100
22
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Initial BPM and quad misalignments (w.r.t. linac axis)Initial BPM and quad misalignments (w.r.t. linac axis)
++ Quadrupole Quadrupole positionspositions
oo BPM offsets BPM offsets
quad positionsquad positions
BPM offsetsBPM offsetsNow launch Now launch beam through beam through undulatorundulator
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Initial trajectory before any correction appliedInitial trajectory before any correction applied
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
fit used to smooth launchfit used to smooth launch
Note, all Note, all trajectory plots are trajectory plots are w.r.t. linac axis w.r.t. linac axis ((except last twoexcept last two) )
‘‘real’ trajectoryreal’ trajectory
quad positionsquad positionsBPM readingsBPM readings
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
130130
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Trajectory after initial rough steering (14.3 GeV)Trajectory after initial rough steering (14.3 GeV)
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
Save as 1Save as 1stst set of BPM set of BPM readingsreadings
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130130
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Energy now reduced to 10 GeVEnergy now reduced to 10 GeV
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
Save as 2Save as 2ndnd set of BPM set of BPM readingsreadings
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
130130
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Energy reduced again to 5 GeVEnergy reduced again to 5 GeV
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
Save as 3Save as 3rdrd set set of BPM of BPM readingsreadings
Now analyze Now analyze BPM data…BPM data…
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130130
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Fitted quadrupole offsetsFitted quadrupole offsets
Fit resultsFit results
Actual offsetsActual offsets
similar plot for similar plot for BPM offsets BPM offsets (not shown)(not shown)
Now correct Now correct quad and BPM quad and BPM positions…positions…
results differ by straight line…results differ by straight line…
‘‘real’ offsetsreal’ offsets
fitted offsetsfitted offsets
use linear component of fitted use linear component of fitted offsets to re-adjust launchoffsets to re-adjust launch
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
130130
130130
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Absolute trajectory after 1st pass of BBA (14.3 GeV)Absolute trajectory after 1st pass of BBA (14.3 GeV)
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
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130130
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
Possible Absolute TrajectoryPossible Absolute Trajectory
LTULTU
Beam is launched straight down undulator, with Beam is launched straight down undulator, with possible inconsequential kink at boundarypossible inconsequential kink at boundary
dispersion generated is insignificantdispersion generated is insignificant
Now look at trajectory w.r.t. undulator axis Now look at trajectory w.r.t. undulator axis
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
After 1st pass of BBA (now w.r.t. undulator line)After 1st pass of BBA (now w.r.t. undulator line)
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
Now repeat Now repeat procedure of procedure of energy changes energy changes two more times…two more times…
xx 48 48 mm
yy 24 24 mm
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
After 3rd pass of BBA (14.3 GeV)After 3rd pass of BBA (14.3 GeV)
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
RON RON (FEL-code) (FEL-code) simulation shows simulation shows LLsatsat increased by increased by
<1 gain-length;<1 gain-length;R. Dejus, R. Dejus, N.VinokurovN.Vinokurov
100°100° 100°100°
xx 1.7 1.7 mmxx 1.7 1.7 mm
yy 2.7 2.7 mmyy 2.7 2.7 mm
rms beam size: rms beam size: 30 30 mm
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130130
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Was confirmed with Was confirmed with GENESIS simulationGENESIS simulation
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator CenterTrajectory After BBA ConvergenceTrajectory After BBA Convergence
Trajectory through undulator at 14 GeV after 3 passes of BBA procedure.Trajectory through undulator at 14 GeV after 3 passes of BBA procedure.
2-2-mm BPM BPM resolutionresolution50-50-mm initial initial BPM & quad BPM & quad offsetsoffsets1-1-mm mover mover backlashbacklash14-7-4.514-7-4.5 GeV GeV 204°204°
2-2-mm BPM BPM resolutionresolution50-50-mm initial initial BPM & quad BPM & quad offsetsoffsets1-1-mm mover mover backlashbacklash14-7-4.514-7-4.5 GeV GeV 204°204°
++ Quadrupole Quadrupole positionspositions
oo BPM readback BPM readback
ee trajectory trajectory
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
BPM read-backs through undulator at 14 GeV (top) and 4.5 GeV (bottom) after rough steering, but before BPM read-backs through undulator at 14 GeV (top) and 4.5 GeV (bottom) after rough steering, but before the BBA procedure. The energy is changed and the launch is re-established. Trajectory changes are the BBA procedure. The energy is changed and the launch is re-established. Trajectory changes are expected at the expected at the 500-500-mm level. level.
500 500 mm
Verify BBA Convergence by noting orbit change from 14 to 4.5 GeVVerify BBA Convergence by noting orbit change from 14 to 4.5 GeVBeforeBefore BBA procedure BBA procedureBeforeBefore BBA procedure BBA procedure
14.1 GeV14.1 GeV
4.5 GeV4.5 GeV
drop energy, drop energy, reset launch, reset launch, note changenote change
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
BPM read-backs through undulator (note scale change) at 14 GeV (top) and 4.5 GeV (bottom) after three BPM read-backs through undulator (note scale change) at 14 GeV (top) and 4.5 GeV (bottom) after three rounds of the BBA procedure, where trajectory changes with energy are expected at the rounds of the BBA procedure, where trajectory changes with energy are expected at the 20-20-mm level. level.
20 20 mm
Verifying BBA ConvergenceVerifying BBA Convergence
AfterAfter BBA procedure BBA procedureAfterAfter BBA procedure BBA procedure
drop energy, drop energy, reset launch, reset launch, note changenote change
14.1 GeV14.1 GeV
4.5 GeV4.5 GeV
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
0.1-Gauss Earth’s field in 0.1-Gauss Earth’s field in xx- direction – perfect system, quads on, no steering- direction – perfect system, quads on, no steering
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
0.1-Gauss Earth’s field in 0.1-Gauss Earth’s field in xx-direction – perfect system, after BBA-direction – perfect system, after BBA
Courtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul EmmaCourtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
0.1-Gauss Earth’s field in 0.1-Gauss Earth’s field in xx-direction – standard errors, after BBA-direction – standard errors, after BBA
no Earth’s field – standard errors, after BBAno Earth’s field – standard errors, after BBA
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Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
0.2-Gauss Earth’s field in 0.2-Gauss Earth’s field in xx-direction – standard errors, after BBA-direction – standard errors, after BBA
Courtesy of Paul Emma Courtesy of Paul Emma Courtesy of Paul Emma Courtesy of Paul Emma
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
SummarySummary
BPMs resolve trajectory to ~1 BPMs resolve trajectory to ~1 m rmsm rms
BPM readings ‘drift’ <1 BPM readings ‘drift’ <1 m over 1-2 hr (temperature)m over 1-2 hr (temperature)
Magnet movers are settable to within Magnet movers are settable to within 1 1 m (or use coils)m (or use coils)
BPM readings are not sensitive to variable beam size, etc.BPM readings are not sensitive to variable beam size, etc.
Trajectory is stable enough to <20% of beam size (already Trajectory is stable enough to <20% of beam size (already demonstrated in FFTB)demonstrated in FFTB)
Earth magnetic field needs to be compensatedEarth magnetic field needs to be compensated
BPMs resolve trajectory to ~1 BPMs resolve trajectory to ~1 m rmsm rms
BPM readings ‘drift’ <1 BPM readings ‘drift’ <1 m over 1-2 hr (temperature)m over 1-2 hr (temperature)
Magnet movers are settable to within Magnet movers are settable to within 1 1 m (or use coils)m (or use coils)
BPM readings are not sensitive to variable beam size, etc.BPM readings are not sensitive to variable beam size, etc.
Trajectory is stable enough to <20% of beam size (already Trajectory is stable enough to <20% of beam size (already demonstrated in FFTB)demonstrated in FFTB)
Earth magnetic field needs to be compensatedEarth magnetic field needs to be compensated
Alignment can be achieved at adequate level Alignment can be achieved at adequate level using beam-based technique, given that…using beam-based technique, given that…
LCLSLCLS
4 4
Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS
BBA Related IssuesBBA Related Issues [email protected]@slac.stanford.edu
Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center
End of Presentation