eexs for bunch compression
DESCRIPTION
EEXs for Bunch Compression. A. Meseck. Motivation: avoid correlated energy deviation Idea:. 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 - PowerPoint PPT PresentationTRANSCRIPT
EEXs for Bunch Compression
A. Meseck
Motivation: avoid correlated energy deviation
Idea:
EEX1Exchange Z↔X
EEX2Exchange X↔ZQuad
focuses XBefore EEX2
A. Meseck
Horizontal phase space
Longitudinal phase space
Exch
ange
d
Exch
ange
d
Dipole=>Ldipol=15m, r=90m
L
L L L
L L
L
L
L1 L1
L=20mL1=10m
Quad=>Lquad=0.5mG=2-3T/mLarge Aperture ~ 10cm
Beam energy= 7.5 GeVHorzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 rms relative energy spread100 pC
~ 280m
Horzontal:Norm.emitt=1.7mm mradBetax=86m+ ISR BUT NO CSRLongitudinal:0.25ps rms pulse duration 1.63e-3 rms relative energy spread100 pC
beam.in
Horizontal phase space
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Horzontal:Norm.emitt=1.7 mm mradDue to ISR! Can not be reduced as there are larger beta-amplitudes involved in the exchange process
Betax=86m (at the end)
X’ [rad]
X [m]
X’ [rad]
X [m]
X’ [rad]
X [m]
BMAD-STANDARD
Longitudinal phase space
Longitudinal:2ps rms pulse duration 2e-4 rms relative energy spread100 pC
Longitudinal:0.25ps rms pulse duration 1.63e-3 rms relative energy spread No way to avoid this!100 pC
σγ/γ
σz [m]
σγ/γ
σz [m]
σγ/γ
σz [m]
BMAD-STANDARD
More realistic phase space distribution+ NO ISRNO CSR
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 rms relative energy spread100 pC
Horzontal:Norm.emitt=0.3mm mradBetax=24m
+ NO ISR, NO CSRLongitudinal:0.23ps rms pulse duration 1.63e-3 rms relative energy spread100 pC
X’ [rad]
X [m]
X’ [rad]
X [m]
σγ/γ
σz [m]
σγ/γ
σz [m]
Taylor map 1 order
More realistic phase space distribution+ NO ISRNO CSR
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 rms relative energy spread100 pC
Horzontal:Norm.emitt=0.315mm mradBetax=23m
+ NO ISR + NO CSRLongitudinal:0.25ps rms pulse duration 1.63e-3 rms relative energy spread100 pC
X’ [rad]
X [m]
X’ [rad]
X [m]
σγ/γ
σz [m]
σγ/γ
σz [m]
Taylor map 3 order
More realistic phase space distribution+ ISRNO CSR
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 rms relative energy spread100 pC
Horzontal:Norm.emitt=1.47mm mradBetax=90m
+ ISR BUT NO CSRLongitudinal:0.25ps rms pulse duration 1.63e-3 rms relative energy spread100 pC
X’ [rad]
X [m]
X’ [rad]
X [m]
σγ/γ
σz [m]
σγ/γ
σz [m]
Taylor map 3 order
More realistic phase space distribution+ NO ISR+CSR
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 relative energy spread100 pC
Horzontal:Norm.emitt=3.18 mm mradBetax=68m
CSR but no ISRLongitudinal:0.247ps rms pulse duration 1.63e-3 rms relative energy spread100 pC
X’ [rad]
X [m]
X’ [rad]
X [m]
σγ/γ
σz [m]
σγ/γ
σz [m]
Taylor map 3 order
More realistic phase space distributionComparison ISR with CSR
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 relative energy spread100 pC
σγ/γ
σz [m]
σγ/γ
σz [m]
X’ [rad]
X [m]
X’ [rad]
X [m]
Taylor map 3 order
More realistic phase space distributionISR + CSR
Horzontal:Norm.emitt=0.3mm mradBetax=30mAlphax=0
Longitudinal:2ps rms pulse duration 2e-4 relative energy spread100 pC
Horzontal:Norm.emitt=3.66 mm mradBetax=65m
CSR and ISRLongitudinal:0.247ps rms pulse duration 1.63e-3 relative energy spread100 pC
X’ [rad]
X [m]
X’ [rad]
X [m]
σγ/γ
σz [m]
σγ/γ
σz [m]
Taylor map 3 order
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-04Final-thridorder 3.14928525E-07 2.30628088E+02 7.46578955E-05 1.63872330E-03Final-ISR-noCSR 1.46982166E-06 9.00624160E+01 7.48045872E-05 1.63882406E-03Final-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-05Final-ISR-noCSR 3.07024662E-07 1.42481898E+02 2.93357319E-05 1.03152631E-03Final-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.