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0 mode studies in LCLS injector gun C.Limborg-Deprey. Frequency analysis of 0-Pi mode Determination of amplitude of 0 mode voltage from Frequency domain method PARMELA simulations. Ratio of 0mode amplitude to pi mode. Ratio of 0mode amplitude to pi mode. WRONG RESONANCE. - PowerPoint PPT Presentation
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Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
0 mode studies in LCLS injector gunC.Limborg-Deprey
• Frequency analysis of 0-Pi mode
• Determination of amplitude of 0 mode voltage from Frequency domain method
• PARMELA simulations
•
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Ratio of 0mode amplitude to pi mode
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Ratio of 0mode amplitude to pi mode
WRONG RESONANCE
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Ratio of 0mode amplitude to pi mode
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Low Power pulse -
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Ratio of 0mode amplitude to pi mode
WRONG RESONANCE
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Ratio of 0mode amplitude to pi mode
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
PARMELA Simulations
Emittance Variation vs Amplitude in the 0 mode
For a 10MV/m amplitude in 0 mode, can there any beneficial effect of the 0 mode?
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
SuperFish Map for PARMELA simulations0 mode
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
PARMELA Simulationswith 0 and Pi modes
Crude simulationsWith 5.5 k particles
PARMELA Simulations
even with 3 MV/m (magenta curve) in the 0 mode, there is some increase in emittance for half of the phases
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
PARMELA Simulationswith 0 and Pi modes
PARMELA Simulations with 20k
particles
• Half of the phases degrade the emittance, the other half improve it
• at 2.852 GHz, a period is 0.5 degrees longer than at 2.856 GHz
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
PARMELA Simulationswith 0 and Pi modes
PARMELA Simulations with 20k
• Half of the phases degrade the emittance, the other half improve it
• at 2.852 GHz, a period is 0.5 degrees longer than at 2.856 GHz
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Looking for better tuning when 0-mode is at = 150
Injection phase does not help Varying pi mode field amplitude helps
BUT
Nearly enough +
Sensitivity to field variation is increased +
Difficulty to find 0-mode = 150
Cecile Limborg-Deprey
0 mode in LCLS injector gun [email protected]
August 28th 2004
Time domain model
3 s Klystron exciting the 0 mode
Rs_0 = 4.94E+06 ;Q0_0 = 12578;Qext_0 = 10000;f_0 = 2.8526e9;
3 s Klystron exciting the PI modeRs_0 = 4.71E+07 ;Q0_0 = 13957;Qext_0 = 6988;f_0 = 2.856e9;
