Feasibility of a ring FEL at low emittance storage rings

Agapov, Ilya

doi:10.1016/j.nima.2015.04.069

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…Linac-based free-electron lasers (FELs) have been a complementary tool to synchrotron light sources for the generation of radiation pulses with high peak brilliance, high degree of coherence and ultrafast resolution (Feng & Deng, 2018). Combining these two techniques has been of remarkable interest to the accelerator community (Kim et al, 1985;Murphy & Pellegrini, 1985;Cornacchia et al, 1986;Nuhn et al, 1992;Huang et al, 2008;Dattoli et al, 2012;Cai et al, 2013;Agapov, 2015;Di Mitri & Cornacchia, 2015;Labat et al, 2007Labat et al, , 2009De Ninno et al, 2008;Khan et al, 2013;Xiang & Wan, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…The self-amplified spontaneous emission (SASE) mechanism (Kondratenko & Saldin, 1980;Bonifacio et al, 1984) has been considered for storage-ring-based FELs (Kim et al, 1985;Murphy & Pellegrini, 1985;Cornacchia et al, 1986;Nuhn et al, 1992;Huang et al, 2008;Dattoli et al, 2012;Agapov, 2015;Di Mitri & Cornacchia, 2015). The SASE output is typically characterized by excellent spatial but limited temporal coherence.…”

Section: Introductionmentioning

confidence: 99%

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Angular dispersion enhanced prebunch for seeding ultrashort and coherent EUV and soft X-ray free-electron laser in storage rings

Wang

Feng

Liu

et al. 2019

J Synchrotron Radiat

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Prebunching is an effective technique to reduce the radiation saturation length and to improve the longitudinal coherence and output stability in storage‐ring‐based free‐electron lasers (FELs). A novel technique is proposed which uses angular dispersion to enhance the high‐harmonic bunching with very small laser‐induced energy spread. This technique can effectively reduce the radiation saturation length without significantly reducing the peak power of the FEL. Numerical simulations demonstrate that this technique can be used for the generation of 100 MW scale level, fully temporal coherent femtosecond extreme‐ultraviolet and soft X‐ray radiation pulses through a 10 m‐long undulator based on a diffraction‐limited storage ring.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Angular dispersion enhanced prebunch for seeding ultrashort and coherent EUV and soft X-ray free-electron laser in storage rings

Wang

Feng

Liu

et al. 2019

J Synchrotron Radiat

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“…High order modes (HOMs) in the cavities and microwave instability, however, would in that case limit the average current to 10 mA. Following the seminal study in [26], magnetic bunch length compression and de-compression in dedicated insertions across an undulator has been sketched for the PETRA-III ring [27]. While promising FEL production in the presence of a multi-bunch filling pattern, the conditions required for lasing in PETRA-III are, however, far from the operational ones: very high charge per bunch (20 nC instead of standard 0.8 nC) and only few RF buckets filled (40 consecutive buckets out of 960 available).…”

mentioning

confidence: 99%

Operating synchrotron light sources with a high gain free electron laser

Mitri

Cornacchia

2015

New J. Phys.

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Since the 1980s synchrotron light sources have been considered as drivers of a high repetition rate (RR), high gain free electron laser (FEL) inserted in a by-pass line or in the ring itself. As of today, the high peak current required by the laser is not deemed to be compatible with the standard multi-bunch filling pattern of synchrotrons, and in particular with the operation of insertion device (ID) beamlines. We show that this problem can be overcome by virtue of magnetic bunch length compression in a ring section, and that, after lasing, the beam returns to equilibrium conditions without beam quality disruption. Bunch length compression brings a double advantage: the high peak current stimulates a high gain FEL emission, while the large energy spread makes the beam less sensitive to the FEL heating and to the microwave instability in the ring. The beam's large energy spread at the undulator is matched to the FEL energy bandwidth through a transverse gradient undulator. Feasibility of lasing at 25 nm is shown for the Elettra synchrotron light source at 1 GeV, and scaling to shorter wavelengths as a function of momentum compaction, beam energy and transverse emittance in higher energy, larger rings is discussed. For the Elettra case study, a low (100 Hz) and a high (463 kHz) FEL RR are considered, corresponding to an average FEL output power at the level of ∼1 W (∼10 13 photons per pulse) and ∼300 W (∼10 11 photons per pulse), respectively. We also find that, as a by-product of compression, the ∼5 W Renieri's limit on the average FEL power can be overcome. Our conclusion is that existing and planned synchrotron light sources may be made compatible with this new hybrid IDs-plus-FEL operational mode, with little impact on the standard beamlines functionality. Background and outlookFree electron lasers (FELs) in the ultra-violet (UV) and x-rays driven by high brightness radiofrequency linear accelerators (RF linacs) [1, 2] have become complementary to synchrotron light sources for the investigation of matter, from molecular to atomic scale. Despite their high peak brilliance and degree of coherence, high gain FELs are surpassed by synchrotrons in number of pulses per second and in number of beamlines that can be served simultaneously. A high repetition rate (RR) of the FEL is a prerequisite for multi-beamline operation; with present technology, it requires a superconducting linac [3-5] and a complex fan-like set of transfer lines [6].Since the 1980s synchrotron light sources have been considered for driving a high gain self-amplified spontaneous emission (SASE) FEL [7,8] in a by-pass line [9][10][11][12][13][14][15][16] or in the ring itself [17], in order to approach RRs of up to 100 kHz without a superconducting linac investment, and taking advantage of existing or planned synchrotron light sources. At present, synchrotron light sources target emittances compatible with lasing at (sub-)nm wavelength [18,19], whereas FELs require emittances at the diffraction limit, 4πε x  λ [20]. Transverse gradient u...

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