Potential diagnostics for the next-generation light sources

There is continued interest in developing a diffraction-limited soft or hard x-ray source. Candidate paths include the storage-ring-based free-electron laser (FEL) and the linac-based self-amplified spontaneous emission (SASE) FEL for the two regimes, respectively. As previously discussed, target beam parameters are {sigma}{sub x,y} {approximately} 10 {micro}m, {sigma}{sub x{prime},y{prime}} = 1 {micro}rad, and {sigma}{sub t} {approximately} 1 ps (0.1 ps for the linac case). The authors report the use of few- to sub-angstrom radiation emitted by a 7-GeV beam transmitting a 198-period diagnostics undulator and a bending magnet to characterize the particle beam. A particle beam divergence as low as {sigma}{sub y{prime}} = 3.3 {micro}rad was measured using an x-ray monochromator. Additionally, a particle beam size of {sigma}{sub y} < 45 {micro}m and a bunch length of {sigma}{sub t} = 28 ps with 4-ps resolution were measured using an x-ray pinhole camera with a unique synchroscan and dual-sweep x-ray streak camera as the detector. The adjustable pinhole aperture was varied by more than a factor of 100 to assess spatial resolution and dynamic range issues in the system. These diagnostics demonstrations should scale to next-generation applications