Undulator Gap Increase [email protected] Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center

Undulator Meeting, June 28 - 29, 2004Undulator Meeting, June 28 - 29, 2004 Heinz-Dieter Nuhn, SLAC / LCLSHeinz-Dieter Nuhn, SLAC / LCLS

Undulator Gap IncreaseUndulator Gap Increase [email protected]@slac.stanford.edu

Linac Coherent Light Source Stanford Synchrotron Radiation LaboratoryStanford Linear Accelerator Center

Undulator Gap IncreaseHeinz-Dieter Nuhn, SLAC / LCLS

June 28, 2004

Undulator Gap IncreaseHeinz-Dieter Nuhn, SLAC / LCLS

June 28, 2004

Problem DescriptionProblem Description Impact on PerformanceImpact on Performance SummarySummary

Problem DescriptionProblem Description Impact on PerformanceImpact on Performance SummarySummary




Problem DescriptionProblem Description

Present baseline design includes gap height of 6.5 Present baseline design includes gap height of 6.5 mmmmResulting in 250 microns or less of clearance on top Resulting in 250 microns or less of clearance on top and bottom of the vacuum chamberand bottom of the vacuum chamberIn order to support the remote roll-away option the In order to support the remote roll-away option the APS requests a 200 microns increase in clearance on APS requests a 200 microns increase in clearance on the top and bottom of the vacuum which the top and bottom of the vacuum which corresponds to a gap increase from 6.5 to 6.9 mmcorresponds to a gap increase from 6.5 to 6.9 mmIf the effect of this gap increase is not compensated If the effect of this gap increase is not compensated bby change in magnet design or magnet material it y change in magnet design or magnet material it will correspond to a reduction in nominal K value will correspond to a reduction in nominal K value from 3.630 to 3.420.from 3.630 to 3.420.Expected performance impact of this reduction in K Expected performance impact of this reduction in K value is being discussed on the following pages.value is being discussed on the following pages.

Present baseline design includes gap height of 6.5 Present baseline design includes gap height of 6.5 mmmmResulting in 250 microns or less of clearance on top Resulting in 250 microns or less of clearance on top and bottom of the vacuum chamberand bottom of the vacuum chamberIn order to support the remote roll-away option the In order to support the remote roll-away option the APS requests a 200 microns increase in clearance on APS requests a 200 microns increase in clearance on the top and bottom of the vacuum which the top and bottom of the vacuum which corresponds to a gap increase from 6.5 to 6.9 mmcorresponds to a gap increase from 6.5 to 6.9 mmIf the effect of this gap increase is not compensated If the effect of this gap increase is not compensated bby change in magnet design or magnet material it y change in magnet design or magnet material it will correspond to a reduction in nominal K value will correspond to a reduction in nominal K value from 3.630 to 3.420.from 3.630 to 3.420.Expected performance impact of this reduction in K Expected performance impact of this reduction in K value is being discussed on the following pages.value is being discussed on the following pages.




Impact of Gap Change IImpact of Gap Change IVARIABLE(Bold=input) UNITS LCLS NOV03 LCLS JUN04

Change LCLS NOV03

LCLS JUN04

Change

Wiggler Type linear linear linear linearr (Radiation wavelength) nm 0.15 0.15 0% 1.50 1.50 0%w (Wiggler period) (used) cm 3.00 3.00 0% 3.00 3.00 0%kw (Wiggler wave number) cm-1 2.094 2.094 0% 2.094 2.094 0%gw (Wiggler gap) cm 0.650 0.690 6% 0.650 0.690 6%Bw (Wiggler peak field)(used) Tesla 1.29587 1.22092 -6% 1.29587 1.22092 -6%K (Wiggler parameter, peak) 3.6300 3.4200 -6% 3.6300 3.4200 -6%aw 2.567 2.418 -6% 2.567 2.418 -6%x,y,ext. (quad) m 30.00 30.00 0% 10.00 10.00 0%n_rms (Normalized rms emittance)

mm mrad 1.200 1.200 0% 2.500 2.500 0%

n,rms/ mm mrad 43.56E-6 45.86E-6 5% 286.99E-6 302.10E-6 5%x (electron distribution rms ) m 34.7 35.7 3% 51.3 52.7 3%'x (electron divergence) m rad 1.25 1.29 3% 5.60 5.74 3%

(Electron energy in unit of .511MeV) 27546.904 26169.287 -5% 8711.096 8275.455 -5%E (Electron Energy) GeV 14.07593 13.37197 -5% 4.45085 4.22824 -5%Ipeak (Peak electron beam current) A 3400.0 3400.0 0% 1920.0 1920.0 0%Peak Beam power GW 47860 45466 -5% 8547 8119 -5%Particle densitiy ne m-3 1.29E+22 1.22E+22 -5% 3.34E+21 3.17E+21 -5% (rms energy spread) 2.800 2.800 0% 2.800 2.800 0% x10-3 0.102 0.107 5% 0.321 0.338 5%

1.5 Angstrom1.5 Angstrom 15.0 Angstrom15.0 Angstrom




Impact of Gap Change IIImpact of Gap Change IIVARIABLE(Bold=input) UNITS LCLS NOV03 LCLS JUN04

Change LCLS NOV03

LCLS JUN04

Change

j (Radiation Beam Radius) (3D) m 49.7 51.0 3% 74.5 76.5 3%Zr (Rayleigh Length) (3D) m 51.65 54.40 5% 11.64 12.25 5%LG (3D) [as in exp [z /LG(3D)] m 4.291 4.370 2% 2.472 2.538 3%

(3D) =w/(4LGsqrt(3)) 321.24E-6 315.43E-6 -2% 557.64E-6 543.13E-6 -3%LE (3D) m 8.581 8.739 2% 4.943 5.076 3%2 Lc (3D) = 2LE r/w m 0.27 0.27 2% 1.55 1.59 3%2 Lc (3D) fs 0.90 0.92 2% 5.18 5.32 3%Psat (saturated power, 3D) corrected MW 8017.571 7355.345 -8% 3987.551 3599.357 -10%Lsat (SASE length to saturation, 3D) cor m 95.33 96.59 1% 57.86 59.07 2%Average Power W 244.6E-3 224.4E-3 -8% 226.7E-3 204.6E-3 -10%Peak Photon Flux Ph/s 6.054E+24 5.554E+24 -8% 3.011E+25 2.718E+25 -10%Average Photon Flux Ph/pulse 1.539E+12 1.412E+12 -8% 1.427E+13 1.288E+13 -10%Average Photon Flux Ph/s 1.847E+14 1.694E+14 -8% 1.712E+15 1.545E+15 -10%ph,x (coherent photon distribution, rms) micron 34.749 35.673 3% 51.287 52.654 3%ph,x' (coherent photon distribution, rms) micro-rad 0.344 0.335 -3% 2.327 2.267 -3%Repetition Rate Hz 120.000 120.000 0% 120.000 120.000 0%Spontaneous Energy per Pulse J 21.4E-3 17.2E-3 -20% 2.3E-3 1.8E-3 -20%Peak Spontaneous Power per Pulse W 84.4E+9 67.6E+9 -20% 4.8E+9 3.8E+9 -20%

Coherent Photons per Pulse 1.539E+12 1.412E+12 -8% 1.427E+13 1.288E+13 -10%Coherent Energy per Pulse mJ 2.038 1.870 -8% 1.889 1.705 -10%Photon Energy keV 8.3E+0 8.3E+0 0% 826.6E-3 826.6E-3 0%

Peak Brilliance [Ph./s/mm2/mr2/.1%] 1.639E+33 1.504E+33 -8% 2.942E+31 2.655E+31 -10%

Ave. Brilliance [Ph./s/mm2/mr2/.1%] 5.001E+22 4.587E+22 -8% 1.672E+21 1.510E+21 -10%1.5 Angstrom1.5 Angstrom15.0 Angstrom15.0 Angstrom




ConclusionsConclusions

AA reduction in nominal K value from 3.630 to 3.420 reduction in nominal K value from 3.630 to 3.420 will reduce the FEL output power (8 %) and increase will reduce the FEL output power (8 %) and increase gain length (1 %).gain length (1 %).

Although the reduction of the number of output Although the reduction of the number of output photons is small, an attempt should be made to photons is small, an attempt should be made to minimize it by reviewing the optimization of the minimize it by reviewing the optimization of the undulator design.undulator design.

AA reduction in nominal K value from 3.630 to 3.420 reduction in nominal K value from 3.630 to 3.420 will reduce the FEL output power (8 %) and increase will reduce the FEL output power (8 %) and increase gain length (1 %).gain length (1 %).

Although the reduction of the number of output Although the reduction of the number of output photons is small, an attempt should be made to photons is small, an attempt should be made to minimize it by reviewing the optimization of the minimize it by reviewing the optimization of the undulator design.undulator design.




End of Presentation

Documents

Undulator Gap Increase [email protected] Linac Coherent Light Source Stanford Synchrotron Radiation Laboratory Stanford Linear Accelerator Center