FERMI@Elettra: First coherent emission recorded

Seeded coherent emission from FEL-1 measured by means of a fast photodiode located in the FERMI@Elettra experimental hall. The undulators were tuned at 43 nm. The green trace shows the time profile of a single pulse with the photodiode in saturation. The yellow trace shows a series o seeded FEL pulses being turned on (left) and off (center-right) by changing the superposition between SEED laser pulses and electron pulses. During the night between December 13 and December 14, 2010, the new free-electron laser (FEL) source FERMI@Elettra seeded at 260 nanometers with an external laser has produced the first coherent emission from the FEL-1 undulator chain tuned at wavelengths of 65 nanometers (fourth harmonic of the seed laser) and 43 nanometers (sixth harmonic).

Sample results are shown in the figure for 43 nanometers. The plot shows in green the signal trace of a fast photodiode located on a beamline in the FERMI experimental hall observing the FEL output. Saturation of the photodiode signal affects the measured profile. The yellow trace shows a wider scan with seeded FEL pulses being turned on and off by varying the superposition of seed laser pulses and electron pulses.

This marks the first successful operation of FERMI@Elettra in its planned configuration, i.e., as a next-generation seeded free-electron laser source. Over the coming months the commissioning team will continue to improve the overall performance of the system and the light will be provided to the first experimental programs.

More information: http://www.elettra.trieste.it/science/update/article.php?20101210

Content: Elettra Website
Date Issued: December 2010

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First lasing of the ALICE FEL

The Infra Red Free Electron Laser installed on the ALICE energy recovery accelerator at STFC Daresbury Laboratory lased for the first time on Saturday 23rd October 2010 at 16:35. Once established, the FEL lased for several hours at about 8 microns wavelength and appeared quite tolerant to the machine settings. A scan of output power vs the cavity length showed the expected detuning behaviour. The maximum output power observed so far is about 30mW. This is the first energy recovery driven FEL to operate within Europe. The FEL spectrum has been measured and this suggests that the FWHM of the light pulse generated is ~800fs long, agreeing well with simulations.

The next step for the project will be to thoroughly characterize the FEL performance and output properties as a function of wavelength, cavity length, etc. More information: www.astec.ac.uk/news/FEL_lasing.htm

Content: ASTeC Website
Date Issued: 27 October 2010

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Science with FLASH

From 27 – 29 September 2010, the workshop “Science with FLASH” took place at DESY in Hamburg. The aim of this meeting was to present recent research conducted at the Free Electron Laser and to inform the user community about new developments and future research perspectives at FLASH after the recent upgrade of the facility. The workshop was jointly organised by DESY and Hamburg University as coordinator of the BMBF priority program FSP 301: FLASH - Matter in the Light of Ultrashort and Extremely Intense X-Ray Pulses (FSP-FLASH).
 
In his welcome address the DESY Photon Science Director Edgar Weckert gave an overview of the major current Photon Science projects at DESY and pointed to the close cooperation of HZB, PSI and DESY concerning the extension of the FLASH facility (FLASH II). Keynote talks and user reports about the scientific work with FLASH during the last user run created a pleasant atmosphere for fruitful conversations and discussions among the 130 participants of the workshop.
 
“The successful experiments so far performed at FLASH show an interesting aspect: with the bundling of expertise of laser, synchrotron and detector physics, larger user collaborations become more and more common,” said Professor Wilfried Wurth from the University of Hamburg and spokesperson of the FSP-FLASH. This trend could play an important role for further EuroFEL activities.
 
The latest news from the FLASH control room came just right for the workshop: On the weekend before the workshop, the FLASH accelerator team had operated the FEL at a new record electron energy of 1.25 giga-electronvolts, providing for the first time stable, intense radiation pulses in the water window at a wavelength of 4.12 nanometres.

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