Shot-by-shot 250 kHz 3D ion and MHz photoelectron imaging using Timepix3

In this work we made use of two Timepix3 cameras to capture images on the two phosphor screens of our double-sided velocity map imaging spectrometer (VMI) allowing for simultaneous ion and electron detection. We were able to deduce the three-dimensional velocity vector for each and every ion observed by analyzing the spatial and temporal information recorded on the event-driven camera at a repetition rate of 250 kHz. Using centroiding, the spatial resolution of the data was improved by an order of magnitude relative to the pixel resolution of the camera. In the same experiment, the photoelectrons were recorded with a repetition rate up to 1 MHz achieving a time resolution of 1.7 ns. The simultaneous recording of the bunchmarker makes it possible to correlate individual ions and electrons with each other as well as with the machine data.

Our results represent a major step toward the implementation of this approach at large-scale facilities such as the European XFEL or LCLS-II or any high-repetition-rate, high-flux light source in general.