A sub-picosecond accumulating streak camera for x-rays

An x-ray streak camera system uses a laser triggered photo-conductive switch to synchronize the high voltage ramp applied to its sweep plates to the photo-excitation of a sample. This technique allows the jitter between successive sweeps to be kept below 100 fs compared to over 1 ps using classical methods. By accumulating a stable pulsed x-ray signal over many sweeps, a very high dynamic range can be achieved whilst maintaining a sub-picosecond time resolution. The ultimate time resolution is limited by the dispersion of electrons in the streak tube. Whilst triggering with a laser at 900 Hz we have achieved a time resolution (FWHM) of 640 fs at a detection wavelength of 267 nm for a 60 s accumulation period, corresponding to over 50 000 sweeps.