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Undulator Tuning Status. Z. Wolf, S. Anderson, R. Colon, S. Jansson, D. Jensen, S.Kaplunenko, Y. Levashov, Ed. Reese, A. Weidemann. Undulator Tuning And Related Topics. Overview Undulator quadrupoles Transportation test Temperature “tests” Repairs Shim-beampipe interference fix
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Undulator Tuning Status Z. Wolf, S. Anderson, R. Colon, S. Jansson, D. Jensen, S.Kaplunenko, Y. Levashov, Ed. Reese, A. Weidemann
Undulator Tuning And Related Topics • Overview • Undulator quadrupoles • Transportation test • Temperature “tests” • Repairs • Shim-beampipe interference fix • Re-tuning status/schedule • Tunnel field map • Reference undulator
Undulator Quadrupoles Finished Scott Anderson (Detailed report in preparation) No Tolerance (individual supplies) No Tolerance No Outliers
Undulator Quadrupoles Finished Tolerance 3 microns Absolute Value Of Magnetic Center Shift In BBA Cycle
Undulator Quadrupoles Finished Difference Between Magnetic And Mechanical Centers
Transportation Test D. Kharakh, Y. Levashov, N. Horton, Y. Levashov, E. Reese Details in LCLS-TN-08-9 During test Outside and undulator temperatures Undulator temperature rise 1° F (0.6 C) Route
Transportation Test Conclusion No significant changes occurred to the undulator during the transportation test.
Temperature “Tests” Y. Levashov, E. Reese Details in LCLS-TN-08-8 Undulator Storage Tlab = 20 ± 0.1 C Building 750, 18 undulators , T = 11 C, 3 checked Building 33, 6 undulators , T = 27 C, 2 checked Building 81 storage, 5 undulators , T = 20 ± 2 C, 1 checked Building 81 laboratory, 1 undulator, T = 20 ± 0.1 C Problem The undulator fiducialization changed. Examples to follow.
Bldg 750 Temperature 20 C ~9 C Temperature ~11 C
Building 750 Gap Change Pole sub-assembly length Field changes agree with gap changes Gap change during storage 1 micron average gap change CMM Hall probe
Building 750 Undulator Changes x-trajectory, y-trajectory, phase errors, all ok But The fiducialization changed by 200 microns in x
Building 33 Temperature J. Chan
Building 81 Lab, Gap Changes T = 20 ± 0.1 C
Temperature Fiducialization Change Summary T = 20 ± 2 C T = 20 ± 0.1 C Undulator 39 T = 11 C T = 27 C err = 50 μm err = 7 μm err = 0.7 μm err = 0.2 μm For ∆K/K = 1.5 × 10-4 ∆xmax = 195 μm ∆ymax = 83 μm ∆gmax = 0.9 μm Conclusion Temperature excursions permanently change the undulator fiducialization.
Trajectories And Phase Are OK Undulator 39 Went through all temperature excursions. Trajectories: no significant change Phase Errors: added ~1° rms
Storage Problem Summary Bldg 750 re-measured undulators The undulators in bldgs 750 and 33 must be re-fiducialized. The trajectories and phases are ok. The average gap changed by about 1 micron. The magnetic axis shifted by about 200 microns in x. 200 microns →∆K/K ≈ 1.8 × 10-4 Tolerance ∆K/K = 1.5 × 10-4 All finished undulators are presently stored in the MMF. A recent air conditioner shutdown does not appear to have damaged them.
Tuning Work A. Weidemann, Y. Levashov, E. Reese • Repair undulators • Fix shim interferences • Re-tune • Re-fiducialize
RepairsBefore repair 130µm Two areas to replace shims Ed Reese
After Repair 50µm Ed Reese
X-Trajectory Shim Interference Fix X-trajectory shim Cut material off • X-trajectory shims limit vacuum chamber “in”-motion to 2.5mm • Undulators tuned for ±6 mm • Shims to be modified to allow - 6mm motion and • Undulator tuning to be checked
Y-Trajectory Shim Interference Fix New Old Fix, new triangles on old strongback
Schedule Yellow items are done. Three undulators still need repair. Eleven undulators have shims replaced, are re-tuned and re-fiducialized. Two have feet and are RFI. (The CMM has been tied up with girders.)
Average Field On Each Girder In The Tunnel S. Anderson, J. Welch By limit From I2y limit for constant field: ∆Bgapmax = 0.09 G By bench By tunnel Shield Atten = 1/6 Pole Amplif = 2.4 By limit ∆Boutsidemax = 0.2 G
Reference Undulator Re-tuning starts K is tuned to the same value each time, Knom = 3.498623 K is adjusted for temperature and X-position. (All errors included in the plot.) R.M.S. = 1.1 × 10-4
Conclusion • Undulator quadrupole measurements are done. • A transportation test showed no undulator changes from handling. • Temperature excursions produce permanent undulator fiducialization changes. • The magnetic field in the tunnel is within the range of the magnetic shield except at a few girders. • Three undulators still require repairs. • Re-tuning is roughly 1/3 done. • Adequate undulator storage is still a problem. (The tunnel is our “planned” solution.)