D. Kosciesza et Hd. Bartunik, Extraction of single bunches of synchrotron radiation from storage rings with an X-ray chopper based on a rotating mirror, J SYNCHROTR, 6, 1999, pp. 947-952
An ultrafast shutter has been developed for alteration of the time structur
e of synchrotron radiation from storage rings in the hard X-ray regime. In
test applications on the wiggler beamline BW6 at DORIS, single bunches were
extracted from the incident pulsed synchrotron radiation with minimum bunc
h-to-bunch distances of 482 ns. Even substantially shorter time windows may
be defined in the case of tight collimation in the incident beam, e.g. on
low-emittance sources. The shutter system is based on a new chopper concept
involving a rotating X-ray mirror which totally reflects the incident radi
ation onto the sample through a remote slit. Rather low rotational velociti
es are sufficient to reach extremely short full open times. An additional s
hutter consisting of a slowly rotating disk prevents frame overlap and cont
rols the repetition rate. A coincidence timing circuit checks the synchroni
zation with the synchrotron bunch clock and provides trigger signals, e.g.
for external excitation of a sample. The chopper system may be used, for ex
ample, in nanosecond time-resolved Laue diffraction experiments.