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LCLS-II Particle Tracking: Gun to Undulator P. Emma Jan. 12, 2011. LCLS-II Accelerator for 13.5 GeV, 120 Hz, 250 pC. 250 MeV z 0.13 mm 1.1 %. 4.2 GeV z 7 m m 0.43 %. 13.5 GeV z 7 m m 0.01 %. 6 MeV z 0.62 mm 0.05 %.
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LCLS-II Particle Tracking: Gun to Undulator P. Emma Jan. 12, 2011
LCLS-IIAccelerator for 13.5 GeV, 120 Hz, 250 pC 250 MeV z 0.13 mm 1.1 % 4.2 GeV z 7 mm 0.43 % 13.5 GeV z 7 mm 0.01 % 6 MeV z 0.62 mm 0.05 % 135 MeV z 0.62 mm 0.07 % undulators L 120 m Linac-X’ L 0.6 m rf -160 V0-19 MV 1-km bypass line Linac-0’ L 6 m 2-13 keV HXR rf gun L0-a,b Linac-3’ L 582 m rf 0° Linac-1’ L 9 m rf -20° Linac-2’ L 326m rf -32° SXR 14-7b 20-4d 11-3b 14-4d ...existing linac 0.24-2 keV LCLS-I 11-1 b,c,d X LCLS-I BC1’ L 6.5 m R56 -46mm BC2’ L 23 m R56 -29 mm DL1’ L 12 m R56 6.3 mm 0.5-10 keV SLAC linac tunnel BTH & U-Hall Jan. 12, 2011, 11:16 AM - PE
LCLS-II Layout (After Linac) m LINAC END LCLS-I LTU1 muon plug wall LTU2 LTUH LTUS LCLS-II
LCLS-II Optics in Elegant (250 pC, 13.5 GeV) Bypass Line 2.4° bends BC1 BC2 HXR und. Thanks to Mark Woodley and Yuri Nosochkov
What’s Included in the Elegant Tracking? • 2E5 macro particles(250pC) tracked through Parmela to 135 MeV. • 1st and 2nd-order optics (dipoles, quads, soln’s) and sinusoidal RF. • Longitudinalwakes of SLAC S-band RF structures. • Resistive longitudinal wakes of 1240 meters of 2-inch diameter stainless steel beam pipe (sector 20-5 to exit of muon-plug wall). • Resistivelongitudinal wakes of 330 meters of 1.625-inch diameter copper plated (?) LTU2 beam pipe. • CSR in all bends (1D model in Elegant) - includes transients but ignores transverse beam size (typically not a big impact). • ISR in all bends – small impact on slice E-spread and slice emittance. • Laser heateradds 17 keV rms E-spread at 135 MeV. • All components are error-free: perfect alignment & CSR-steering is removed.
LCLS-II Particle Distributions (in Longitudinal Phase Space) 35 A Output from Parmela at 135 MeV Output from Elegant at 14 GeV 0.01% rms ~3 kA …with CSR
CSR-Induced Emittance Growth Along BC2 (250 pC, 4.2 GeV) Includes double-horn distribution of LCLS 1.32 mm 1.09 mm gex gey 0.53 mm This calculation removes the linear correlations in x and x’ with energy in order to reveal only the irrecoverable CSR effect. The projected emittance after the BC2 without removing these linear correlation is 1.32 mm.
CSR-Induced Slice Emittance Before and After BC2 (250 pC, 4.2 GeV) Includes double-horn distribution of LCLS Slice Emittance Before BC2 Slice Emittance After BC2
CSR-Induced Emittance Growth Along LCLS-II Accelerator (13.5 GeV) Includes double-horn distribution of LCLS might be fixed? LTU2 2.4-deg Bends Vertical Bends Bypass Dog-Leg BC1 BC2
CSR-Induced Emittance Growth Along LTU2 & LTUS (13.5 GeV) Includes double-horn distribution of LCLS pulsed bend 2.4° bends LTUS DL-bends Emittance across LTU2 bend system (horizontal in black and vertical in blue), including the 2.4-deg bends and the LTUS SXR branch line optics (8 dipoles total).
Resistive-Wall Longitudinal Wakefield of 1240-m of 2-inch SS Pipe (Existing Bypass Line) Bane, Sands
Resistive-Wall Longitudinal Wakefield of 1240-m of 2-inch SS Pipe (Existing Bypass Line) Before bypass linev After bypass line
Final Slice Emittances (x & y) - with CSR - Before Undulator (250 pC, 13.5 GeV)