Pulse Stacker for the Photoinjector Laser System
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Siegfried Schreiber, DESY email: [email protected] Principles Measurements with the TTF1 laser Thanks to Knut Partes and Karsten Klose for their participation in this work Pulse Stacker for the Photoinjector Laser System TESLA Collaboration Meeting, WG3 January 21-23, 2004 DESY-Zeuthen
Transcript of Pulse Stacker for the Photoinjector Laser System
Siegfried Schreiber, DESY
email: [email protected]
PrinciplesMeasurements with the TTF1 laser
Thanks to Knut Partes and Karsten Klose for their participation in this work
Pulse Stacker for the Photoinjector Laser System
TESLA Collaboration Meeting, WG3
January 21-23, 2004
DESY-Zeuthen
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen2
TTF 2 Laser Upgrade
Together with Max-Born-Institute, Berlin (I. Will et al.)Upgrade has been tested at PITZ
diode-pumpedNd:YLF preamplifier
Pulse shaper(T = 5 %)
Diode-pumpedNd:YLF oscillator
Emicro = 16 µJP = 16 W
AOM
f round trip= 27 MHz
EOMAOM
Faraday
pulsepicker
pulsepicker
2-stage flashlamp-pumpedNd:YLF booster amplifier
fastcurrentcontrol
shot-to-shotoptimizer
2-stage diode-pumpedNd:YLF amplifier
fastcurrentcontrol
fourthharm.
Emicro = 200µJP = 200 W
20 ps flat-top4 ps edges
Emicro = 30 µJEburst = 24 mJUV (262 nm)
pum
p di
ode
pum
p di
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pum
p di
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pum
p di
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pum
p di
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pum
p di
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pum
p di
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pum
p di
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Pulse Stacker
Note:
longitudinal flat profile by pulse stacker only
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen3
Why do we need a stacker?
First, as a guideline, the transverse emittance is smaller for rectangular shaped bunches in both planes, longitudinal and transverse.A gaussian shaped bunch has a different space charge behavior inits core as in its wings.Second, in contrast to TTF1, the laser now is prepared to reach the design goal, a 20 ps flat-hat pulse with sharp rise times.Thus, its pulses are still gaussian, but shorter, by a factor of 2 compared to TTF1 (estimate sigma of 3.5 ps)To reduce space charge effects, flat-hat pulses are required, even without a 3rd harmonic cavityOpen is, to which extend we should stack, probably a 10 ps flat-hat is sufficient.
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen4
The Splitting Principle
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen5
Stacker for Four Stacked Pulses
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen6
Pulse Stacker set-up on the laser table
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen7
Example of a Measured Profile (7 ps laser)
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen8
Series of Measured Profiles
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen9
Polarization Imperfection of the Splitters
Siegfried Schreiber, DESY * TESLA Collaboration Meeting, WG3 January 21-23, 2004, DESY Zeuthen10
Summary
The pulse stacker has been set-up and tested with the TTF1 laser systemTransmission efficiency about 75 %It will be used until the MBI pulse shaper is ready to be installed at DESYMay stack 2 or 4 pulses or may be bypassed alloverMeasurements of the longitudinal electron bunch shape for different stacker settings required. However, once set-up, no or little adjustments required occasionally
