One picosecond. That’s how long it takes for a burst of electrons to flash through the Linac Coherent Light Source II at SLAC National Accelerator Laboratory—and now, thanks to a breakthrough detector developed by physicists across California and New Mexico, that’s also the smallest slice of time we can reliably capture in high-rate particle beams. This sliver of duration, just one trillionth of a second, is where the future of ultrafast science unfolds. As next-generation accelerators push toward a staggering 1 million pulses per second—up from today’s standard of 120—existing diagnostics falter. The new diamond-based system, engineered by the Advanced Accelerator Diagnostics Collaboration, doesn’t just keep up; it redefines what’s possible.

The challenge was clear: traditional detectors couldn’t survive the intensity and repetition of emerging accelerator beams, let alone deliver precise, real-time data. Without accurate diagnostics, even the most powerful machines become blind to the atomic-scale dynamics they’re built to observe. Enter a collaboration spanning UC Santa Cruz, UC Davis, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, and SLAC. Together, they redesigned the entire detection chain—from sensor to signal processing—centered on a synthetic diamond sensor no larger than a fingernail. Diamond, with its extreme durability and unmatched thermal conductivity, acts as the ideal medium for capturing high-energy particles without degrading. But the real innovation lies in the integration: a custom-designed readout microchip, known as an FPS ASIC, processes signals in real time, while advanced packaging techniques minimize noise and delay.

In July 2025, the team tested the full system at SLAC, exposing it to 1-picosecond electron bursts. The results, published in Physical Review Accelerators and Beams, stunned even the developers. The detector produced clean, sharply defined signals lasting just 125 picoseconds—eight times faster than a nanosecond—with remarkable consistency across a wide dynamic range. “It performed extremely well, better than we expected,” said Bruce Schumm, the Long Family Professor of Experimental Physics at UC Santa Cruz. “And not only that, but if we compare the performance to our pure calculation expectations, they agree with stunning accuracy.”

Now, a second-generation system is in development, featuring an upgraded ASIC chip optimized specifically for the diamond sensor, with signal response times expected to improve further. The team is also working to make the system more accessible, aiming for a plug-and-play version that labs worldwide can deploy without specialized expertise. Beyond particle physics, the technology holds promise for fusion energy research, ultrafast laser systems, and materials science—any field where observing atomic motion in real time is critical. As Schumm puts it, “The more and more that we look at things, the more and more we need to understand things at the atomic scale.” With this detector, we’re no longer guessing. We’re watching.