Table 1.

Basic parameters of the European XFEL in comparison with those of the two operating hard X-rays FEL projects; brilliances are expressed in photons s⁻¹ mrad⁻² mm⁻² per 0.1%BW.

facility	LCLS	SACLA	European XFEL (SASE1 undulator)
max. electron energy (GeV)	14.3	8.0	17.5
min. photon wavelength (nm)	0.15	0.06	<0.05
photons per pulse	approximately 1012	2×1011	approximately 1012
peak brilliance	approximately 8×1032	approximately 1033	5×1033
average brilliance	2×1021	3×1020	approximately 1025
pulses per second	120	60	27 000
date of first beam	2009	2011	2016