LCLS-II Magnet Error Sensitivities

Sensitivities of dipole magnets, from injector output (95 MeV) to SXR undulator input (4 GeV), where each plotted point increases the geometric mean of the x and y projected emittances by 2%. Dipole magnet field quality sensitivities are shown at top (|b 1 /b 0 | as relative quadrupole field normalized to dipole field at r = 10 mm and |b 2 /b 0 | as relative sextupole field normalized to dipole field at r = 10 mm), and dipole magnet roll angle sensitivities are shown at bottom. Field quality sensitivities in the BC1 and BC2 magnets are tight (e.g., |b 2 /b 0 | < at r = 10 mm as the worst case), but roll sensitivities are reasonable (|  | < 1 mrad as the worst case). Sensitivity of Dipole Magnets (gradient, sextupole, and roll) BC1 BC2 10  3 (r = 10 mm) 1 mrad

Sensitivity of Quadruple Magnets (x & y alignment and roll) Sensitivities of quadrupole magnets, from injector output (95 MeV) to SXR undulator input (4 GeV), where each plotted point increases the geometric mean of the x and y projected emittances by 2%. Quadrupole magnet transverse alignment sensitivities are shown at top (|  x tol | and |  y tol |), and quadrupole magnet roll angle sensitivities are shown at bottom. Alignment sensitivities are not very tight with many at the millimeter level and |  x tol | < 0.1 mm as the worst case, and roll sensitivities are also reasonable (e.g., |  tol | < 10 mrad as the worst case). 1 mm 10 mrad

Sensitivity of Quadruple Magnets (sextupole and gradient error) Sensitivities of quadrupole magnets, from injector output (95 MeV) to SXR undulator input (4 GeV), where each plotted point increases the geometric mean of the x and y projected emittances by 2%. Quadrupole magnet field quality sensitivities are shown at top (|b 2 /b 1 |) as relative sextupole field normalized to quadrupole field at r = 10 mm, and quadrupole magnet relative field strength error sensitivities are shown at bottom. Field quality sensitivities are not very tight (e.g., |b 2/ b 1 | < 1 % as the worst case), and relative field strength error sensitivities are also reasonable (e.g., |  B/B 0 | < 0.3% as the worst case). 10% (r = 10 mm) 1%

Sensitivity of Quadruple Magnets (vibration and chromatic aberration) Sensitivities of quadrupole magnets, from injector output (95 MeV) to SXR undulator input (4 GeV). Quadrupole magnet transverse vibration sensitivities are shown at top (   x,   y ) where each plotted point will add 5% rms transverse jitter (normalized to the nominal rms beam size) in the undulator, and the quadrupole magnet chromatic sensitivities are shown at bottom, where each plotted point is the relative emittance growth of that one quadrupole magnet due to its focal length dependence on particle energy (and relative energy spread at that magnet). Vibration sensitivities are fairly tight (e.g.,   y < 0.1 mm as the worst case), but chromatic sensitivities in the injector are somewhat large (e.g., |  y /  y |  5% as the worst case).