Time delay measurement in the frequency domain

J Synchrotron Radiat. 2015 Sep;22(5):1293-6. doi: 10.1107/S1600577515014095. Epub 2015 Aug 6.


Pump-probe studies at synchrotrons using X-ray and laser pulses require accurate determination of the time delay between pulses. This becomes especially important when observing ultrafast responses with lifetimes approaching or even less than the X-ray pulse duration (∼100 ps). The standard approach of inspecting the time response of a detector sensitive to both types of pulses can have limitations due to dissimilar pulse profiles and other experimental factors. Here, a simple alternative is presented, where the frequency response of the detector is monitored versus time delay. Measurements readily demonstrate a time resolution of ∼1 ps. Improved precision is possible by simply extending the data acquisition time.

Keywords: RF frequency analysis; X-ray synchrotron; pump–probe; ultrafast time resolution.

Publication types

  • Research Support, Non-U.S. Gov't