Shot noise startup of the 6 nm SASE FEL at the TESLA test facility

Abstract

We present here the results of an extensive simulation activity for the TESLA SASE FEL. We have used the program GINGER to determine the FEL saturation length and its fluctuations from shot to shot. The spectral properties of the output power and the correlation functions are investigated and compared with available theoretical models.

Frequency response of an atomic resonance driven by weak free-electron-laser fluctuating pulses

“…All of these properties are in agreement with experimental observations and theoretical results pertaining to various SASE-FEL facilities [11,12,13,20].…”

“…In the following we focus on the generation of fluctuating pulses with Gaussian correlated noise, which is the type of correlations typically observed in different SASE FEL facilities [11,12,13,20,21,22]. To this end, the algorithm of Sec.…”

longitudinal space charge assisted echo seeding of a free electron laser

“…The FEL community has pursued methods to improve the temporal coherence properties of the light [1][2][3][4][5][6][7] and to generate shorter, tunable FEL pulses [5][6][7][8][9][10][11][12]. When the temporal coherence of FEL light is determined by the shot noise of an electron beam, as in Self Amplified Spontaneous Emission (SASE), it is poor [13][14][15] but if it is determined by an external seed laser, the FEL light takes on the excellent temporal coherence properties of the external laser in the region which has been seeded. However, if the seed pulse is short while the electron bunch is long, the noisy SASE background signal can overwhelm the seeded radiation, wiping out the benefits of the seed.…”

Output characteristics of SASE-driven short-wavelength FELs

“…7 >> l c / c ) such as the effective input signal strength, the narrowing of RMS spectral width versus 2 together with the corresponding growth of the autocorrelation time, and the average saturation power. Relatively little work has been done concerning radiation properties on the microscopic time scale of individual spikes, apart from confirming that the RMS intensity fluctuation (< I 2 > -< I >?…”