文档介绍：Longitudinal profile
Summary
PETRA Laserwire Laser
Laserwire Meeting
26 Feb 2004 DESY
The Laser
The laser has been given to us by B. Dehning (thanks Bernd) from CERN. It has been used at LEP to measure beam polarization
It’s a Nd:YAG Q-switched system, running with 30 Hz
pulse energy measured: 40 mJ, power: 4 MW
synchronization to PETRA beam by triggering the Q-switch Pockels-cell
transverse beam quality is modest (multimode)
measured spot size at IP: σL = (50 ± ?) μm
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Schreiber/Sertore TTF Workshop AmrumLaserwire Meeting DESY 26-Feb-2004
Measurement of the longitudinal Profile
The longitudinal profile has been measured with a streak camera: FESCA 200 from Hamamatsu
largest window of the camera: 500 ps with a resolution of 5 ps (fwhh)
The camera was triggered with the laser via a fast photo diode
Problem: stability of the trigger probably not better then ns
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Schreiber/Sertore TTF Workshop AmrumLaserwire Meeting DESY 26-Feb-2004
Averaged Profile
Measured averaged profile (sum of alls bin contents after bgd substraction) fits to gaussian with a width of ns (as expected)
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Schreiber/Sertore TTF Workshop AmrumLaserwire Meeting DESY 26-Feb-2004
Structure in the Longitudinal Profile
Example of a single shot measurement of the profile 500 ps window, resolution 5 ps
60 ps
66 ps
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Schreiber/Sertore TTF Workshop AmrumLaserwire Meeting DESY 26-Feb-2004
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