Electron Beam Metamorphose for Correlated Energy Deviation Avoidance
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Explore electron beam metamorphosis for energy deviation avoidance in Bunch Compression to optimize energy spread and pulse duration. Utilize exchanges and phase space modifications.
Electron Beam Metamorphose for Correlated Energy Deviation Avoidance
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Presentation Transcript
EEXs for Bunch Compression A. Meseck
Motivation: avoid correlated energy deviationIdea: Electron beam metamorphose EEX1 Exchange Z↔X EEX2 Exchange X↔Z Quad focuses X Before EEX2 A. Meseck
Horizontal phase space Beam energy= 7.5 GeV Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 Longitudinal: 2ps rms pulse duration 2e-4 rms relative energy spread 100 pC Exchanged L L L Exchanged L1 L1 L Horzontal: Norm.emitt=1.7mm mrad Betax=86m + ISR BUT NO CSR Longitudinal: 0.25ps rms pulse duration 1.63e-3 rms relative energy spread 100 pC beam.in 2m ; ~30MeV L L 2m; ~30MeV L Quad=> Lquad=0.5m G=2-3T/m Large Aperture ~ 10cm L L=20m L1=10m Dipole=> Ldipol=15m, r=90m ~ 280m Longitudinal phase space
BMAD-STANDARD X’ [rad] X’ [rad] X’ [rad] X [m] X [m] X [m] Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 Horzontal: Norm.emitt=1.7 mm mrad Due to ISR! Can not be reduced as there are larger beta-amplitudes involved in the exchange process Betax=86m (at the end) Horizontal phase space
BMAD-STANDARD σγ/γ σγ/γ σγ/γ σz [m] σz [m] σz [m] Longitudinal: 2ps rms pulse duration 2e-4 rms relative energy spread 100 pC Longitudinal: 0.25ps rms pulse duration 1.63e-3 rms relative energy spread No way to avoid this! 100 pC Longitudinal phase space
Taylor map 1 order More realistic phase space distribution + NO ISR NO CSR X’ [rad] X’ [rad] σγ/γ σγ/γ Horzontal: Norm.emitt=0.3mm mrad Betax=24m Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 X [m] X [m] σz [m] σz [m] + NO ISR, NO CSR Longitudinal: 0.23ps rms pulse duration 1.63e-3 rms relative energy spread 100 pC Longitudinal: 2ps rms pulse duration 2e-4 rms relative energy spread 100 pC
Taylor map 3 order More realistic phase space distribution + NO ISR NO CSR σγ/γ X’ [rad] X’ [rad] σγ/γ Horzontal: Norm.emitt=0.315mm mrad Betax=23m Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 X [m] σz [m] σz [m] X [m] + NO ISR + NO CSR Longitudinal: 0.25ps rms pulse duration 1.63e-3 rms relative energy spread 100 pC Longitudinal: 2ps rms pulse duration 2e-4 rms relative energy spread 100 pC
Taylor map 3 order More realistic phase space distribution + ISR NO CSR σγ/γ X’ [rad] X’ [rad] σγ/γ Horzontal: Norm.emitt=1.47mm mrad Betax=90m Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 X [m] σz [m] σz [m] X [m] + ISR BUT NO CSR Longitudinal: 0.25ps rms pulse duration 1.63e-3 rms relative energy spread 100 pC Longitudinal: 2ps rms pulse duration 2e-4 rms relative energy spread 100 pC
Taylor map 3 order More realistic phase space distribution + NO ISR +CSR X’ [rad] X’ [rad] σγ/γ σγ/γ Horzontal: Norm.emitt=3.18 mm mrad Betax=68m Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 X [m] X [m] σz [m] σz [m] CSR but no ISR Longitudinal: 0.247ps rms pulse duration 1.63e-3 rms relative energy spread 100 pC Longitudinal: 2ps rms pulse duration 2e-4 relative energy spread 100 pC
Taylor map 3 order More realistic phase space distribution Comparison ISR with CSR σγ/γ σγ/γ X’ [rad] X’ [rad] Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 σz [m] σz [m] X [m] X [m] Longitudinal: 2ps rms pulse duration 2e-4 relative energy spread 100 pC
Taylor map 3 order More realistic phase space distribution ISR + CSR X’ [rad] X’ [rad] σγ/γ σγ/γ Horzontal: Norm.emitt=3.66 mm mrad Betax=65m Horzontal: Norm.emitt=0.3mm mrad Betax=30m Alphax=0 X [m] X [m] σz [m] σz [m] CSR and ISR Longitudinal: 0.247ps rms pulse duration 1.63e-3 relative energy spread 100 pC Longitudinal: 2ps rms pulse duration 2e-4 relative energy spread 100 pC
7.5 GeV beam (rf curvature included): norm_emitt _x beta_x rms pulse length rms energy spread Initial 3.00000000E-07 3.00000000E+01 5.99585000E-04 2.00000000E-04 Final-thridorder 3.14928525E-07 2.30628088E+02 7.46578955E-05 1.63872330E-03 Final-ISR-noCSR 1.46982166E-06 9.00624160E+01 7.48045872E-05 1.63882406E-03 Final-ISR-CSR 3.66210475E-06 6.53924997E+01 7.41145508E-05 1.63599854E-03 1GeV beam (rescaled EEX Compressor ; rf curvature not included, BMAD-STANDARD): norm_emitt _x beta_x rms pulse length rms energy spread Initial 3.00000000E-07 3.00000000E+01 5.99585000E-04 5.00000000E-05 Final-ISR-noCSR 3.07024662E-07 1.42481898E+02 2.93357319E-05 1.03152631E-03 Final-ISR-CSR 4.49764204E-06 2.69827366E+01 3.24663673E-05 1.00185760E-03 According to Zholents (PAC2011), there is a chance that an increase in initial betafuction reduces the 2D CSR.