1Brilliance is photon flux per mm2 per mrad2 per 0.1% energy bandwidth of the beam: a brilliant beam is both highly parallel and has a tiny `source size'. Brilliance is directly linked to the property of a storage-ring electron beam called `emittance', which describes the size and angular trajectory of the circulating electron beam.
2Insertion devices are magnetic elements inserted into straight sections which locally modify the electron-beam trajectory and hence can produce synchrotron radiation with different characteristics to that emitted by a bending magnet.