I am going through currently the experiments on "Ultrafast electron Diffraction" under "Structural dynamics". Without taking into consideration all the details of such a complicated set up and just only considering an overall working principle of the experiment Would you kindly throw any light whether there is any kind of relativistic Doppler shift, which is suffered by the electron (Probe) pulse from experimental data or experimental setup.
In this regard, this is further to mention that in the experiment, the electron pulse is passed through the Radio-Frequency cavity before reaching the sample. It is also learnt that this RF cavity can be used for creating both temporally focusing or defocusing effect of the beam, as requisite for the experimental setup. Therefore, it can be assumed that this RF cavity can be functioned as a frequency controller device.
Would you kindly tell me whether my assumption is right or wrong or suggest me any relevant text, from where I can get some help.