The X-ray light is generated by
self-amplified spontaneous emission (SASE), where electrons interact with the radiation that they or their neighbours emit. The result is spontaneous emission of tightly bunched packages of radiation that are amplified like laser light. The peak brilliance of the European XFEL is billions of times higher than that of conventional X-ray light sources, while the average brilliance is 10,000 times higher.
 The higher electron energy allows the production of shorter wavelengths.
 The duration of the light pulses can be less than 100