Application of an Event-Based Camera for Real-Time Velocity Resolved Kinetics

Abstract

We describe here the application of an inexpensive event-based/neuromorphic camera in an ion imaging experiment operated at 1 kHz detection rate to study real-time velocity-resolved kinetics of thermal desorption. Such measurements involve a single gas pulse to initiate a time-dependent desorption process and a high repetition rate laser, where each pulse of the laser is used to produce an ion image. The sequence of ion images allows the time dependence of the desorption flux to be followed in real time. In previous work where a conventional framing camera was used, the large number of megapixel-sized images required data transfer and storage rates of up to 16 GB/s. This necessitated a large onboard memory that was quickly filled and limited continuous measurement to only a few seconds. Read-out of the memory became the bottleneck to the rate of data acquisition. We show here that since most pixels in each ion image contain no data, the data rate can be dramatically reduced by using an event-based/neuromorphic camera. The data stream is thus reduced to the intensity and location information on the pixels that are lit up by each ion event together with a time-stamp indicating the arrival time of an ion at the detector. This dramatically increases the duty cycle of the method and provides insights for the execution of other high rep-rate ion imaging experiments.

Application of Laser Induced Desorption to study Velocity-Resolved Kinetics

“…Real-time kinetics use a detection laser with kHz repetition rate to measure the whole kinetic trace during a single MB pulse with a resolution of at least 1 ms [97]. We recently published a paper about real-time kinetics using an event based camera [98] for VRK. This approach is not compatible with LID-VRK because the LID laser pulse desorbes a significant portion of the coverage, which would interfere with the subsequent data points.…”