P. Emma P. Emma LCLS FAC LCLS FAC [email protected][email protected]u 12 Oct. 2004 12 Oct. 2004 Comments from Comments from LCLS LCLS FAC FAC Meeting (April Meeting (April 2004): 2004): J. R J. R oß oß bach: bach: “How do you detect “How do you detect weak FEL power when the gain is weak FEL power when the gain is very low (few hundred)?” very low (few hundred)?” K. Robinson: K. Robinson: “Can you modulate “Can you modulate the laser heater in some way to the laser heater in some way to help FEL signal detection?” help FEL signal detection?” Laser-Heater Modulation Laser-Heater Modulation P. Emma, Z. Huang, J. Wu P. Emma, Z. Huang, J. Wu
Laser-Heater Modulation P. Emma, Z. Huang, J. Wu. Comments from LCLS FAC Meeting (April 2004): J. R oß bach: “How do you detect weak FEL power when the gain is very low (few hundred)?” K. Robinson: “Can you modulate the laser heater in some way to help FEL signal detection?”. - PowerPoint PPT Presentation
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Comments from Comments from LCLSLCLS FACFAC Meeting (April 2004): Meeting (April 2004):
J. RJ. Roßoßbach:bach: “How do you detect weak FEL power when the “How do you detect weak FEL power when the gain is very low (few hundred)?”gain is very low (few hundred)?”
K. Robinson:K. Robinson: “Can you modulate the laser heater in some “Can you modulate the laser heater in some way to help FEL signal detection?”way to help FEL signal detection?”
Comments from Comments from LCLSLCLS FACFAC Meeting (April 2004): Meeting (April 2004):
J. RJ. Roßoßbach:bach: “How do you detect weak FEL power when the “How do you detect weak FEL power when the gain is very low (few hundred)?”gain is very low (few hundred)?”
K. Robinson:K. Robinson: “Can you modulate the laser heater in some “Can you modulate the laser heater in some way to help FEL signal detection?”way to help FEL signal detection?”
Laser-Heater ModulationLaser-Heater ModulationP. Emma, Z. Huang, J. WuP. Emma, Z. Huang, J. Wu
Simulate LCLS (Linac + M. Xie) with linac jitter, large emittance Simulate LCLS (Linac + M. Xie) with linac jitter, large emittance (3 (3 m), spontaneous radiation background, and laser-heater m), spontaneous radiation background, and laser-heater modulated at 7 Hz (or other unique frequency << 120 Hz)modulated at 7 Hz (or other unique frequency << 120 Hz)
1.5-1.5-ÅÅ LCLSLCLS, except , except x,yx,y == 3.6 3.6 mm
2% rms charge jitter2% rms charge jitter0.5 ps rms gun-timing jitter0.5 ps rms gun-timing jitter0.1-deg rms RF phase jitter (each of 4 linacs)0.1-deg rms RF phase jitter (each of 4 linacs)0.1% rms RF amplitude jitter (each of 4 linacs)0.1% rms RF amplitude jitter (each of 4 linacs)2% rms emittance jitter2% rms emittance jitterincludes small emittance growth in laser-heaterincludes small emittance growth in laser-heater10-MW spontaneous power (1% BW cut)*10-MW spontaneous power (1% BW cut)*10% rms radiation energy measurement noise10% rms radiation energy measurement noise
fast, accurate 2fast, accurate 2ndnd-order linac -order linac model in model in MatlabMatlab, with jitter, with jitter
Modulate Slice Energy Spread with HeaterModulate Slice Energy Spread with Heater(Square-wave suggested by Gennady Stupakov)(Square-wave suggested by Gennady Stupakov)
P. EmmaP. Emmaaa, W. Fawley, W. Fawleybb, Z. Huang, Z. Huangaa, ,
S. ReicheS. Reichecc, G. Stupakov, G. Stupakovaa, ,
a)a) SLACSLAC, , b)b) LBNLLBNL, , c)c) UCLAUCLA
First proposed by A. Zholents (LBNL)First proposed by A. Zholents (LBNL)Submitted to PRLSubmitted to PRLLCLS study published in FEL’04 proc.LCLS study published in FEL’04 proc.
SummarySummaryShorter gain length, higher power, ~same average powerShorter gain length, higher power, ~same average power
Adjustable x-ray pulse duration by changing laser pulseAdjustable x-ray pulse duration by changing laser pulse
Nearly temporally coherent and transform limited radiation Nearly temporally coherent and transform limited radiation within spike with random carrier phase between spikes - within spike with random carrier phase between spikes - solitary attosecond x-ray pulsesolitary attosecond x-ray pulse
Absolute synch. between laser pulse and x-ray pulseAbsolute synch. between laser pulse and x-ray pulse