This 2nd edition of the FELs of Europe Topical Workshop on Selected Problems in FEL Physics is divided into two parts:
- the main event from Wednesday to Friday,
- a satellite meeting, focusing on the topic of advanced synchronization systems.
This event is funded to a large part by FELs of Europe https://www.fels-of-europe.eu/
and organized this year by European XFEL GmbH and DESY.
Previous event 2022 : https://www.fels-of-europe.eu/e212752/e214604/e313168
The FERMI Optical Timing system started its operations in 2009 demonstrating the high reliability of optical technologies to achieve femtosecond level performances for phase reference distribution and synchronization. After the completion of the progressive installation of the system, the main focus was on improving the operations and the uptime. At present a major upgrade on the pulsed subsystem is currently in progress to increase the number of stabilized links.
vouchers for the cantine will be handed out.
Selected Topics on State-of-the art Techniques and Current Challenges
The seed laser of FERMI generates the UV pulses that seed the FEL and the IR pulses delivered to the beamlines for pump-probe experiments. The implemented tight synchronization of the local laser oscillator to the optical timing system and the stabilization of the time of flight across the regenerative amplifier secure better then 5 fs RMS jitter of the seed pulses with respect to the timing reference. In the pump-probe experiments the timing jitter is also typically better then 5fs RMS over tens of minutes.
In order to maintain the proper timing between the seed laser pulse and the electron bunch we compensate the delay of the UV pulses during the wavelength changes caused by the optical parametric amplifier timing and an additional feedback system correlates the BAMs with the FEL intensity, adjusting the seed laser arrival time in order to compensate drifts due to e-beam and UV beam transport drifts. The talk will present details on the updated optical setups, including the upgrade for implementing the EEHG scheme where 2 seed pulses delivered to different locations need to be provided.
Selected Topics on Near Future Challenges
There are three topics that we would like to investigate to improve the laser performance at FERMI in the near future:
- A time stabilization system for the long transport of the seed laser to experimental stations aimed at cancelling the long term drift in the pump-probe experiments, might be based on LAM
- A robust BOCC to synchronize a second Ti:Sa oscillator to the main one, i.e. 2 pulses at 800nm (the current system is designed for 1500 and
800 nm), in order to decouple the optical parameters of the pulse produced for pump-probe experiments from the one required for the FEL.
- Studies aimed at better understanding of the dynamic response of the phase of a Ti:Sa oscillators versus the voltage applied to the piezo actuator, in order to improve the frequency response of the control loop and the quality of the locking
Fingerfood (incl. vegan options) will be offered,
along with drinks (incl. beer and wine)
Guided tour through FLASH2 tunnel and FLASH experimental halls ("Albert-Einstein" and "Kai Siegbahn") with photon beamlines and experimental end-stations.
You find details in the attached pdf.
09:00 meeting at bld. 28c, FEL hall seminar room
09:10 tour through FLASH 2 tunnel
09:40 tour through FLASH 2 experimental hall
10:10 overview of FLASH 1 experimental hall
10:20 end of tour
09:10 meeting at bld. 28c, FEL hall seminar room
09:20 tour through FLASH 2 experimental hall
09:50 overview of FLASH 1 experimental hall
10:10 tour through FLASH 2 tunnel
10:30 end of tour
09:20 meeting at bld. 28c, FEL hall seminar room
09:30 tour through FLASH 2 tunnel
10:00 overview of FLASH 1 experimental hall
10:10 tour through FLASH 2 experimental hall
10:40 end of tour
Lunch boxes as take-away will be offered.