Physicists have built what they describe as the best-performing high-bandwidth particle detection system constructed to date, one capable of measuring electron bursts lasting just one picosecond.
The work came out of the Advanced Accelerator Diagnostics Collaboration, a group that includes two University of California campuses and three national laboratories: Lawrence Berkeley, Los Alamos, and UC Davis. According to Phys.org, the results are published in the journal Physical Review Accelerators and Beams.
The problem the team set out to solve is a practical one. Next-generation particle accelerators are moving from 120 pulses per second to 1 million pulses per second, and eventually beyond 1 billion per second. At those speeds, existing detection systems simply fail. Researchers using those accelerators need to measure the beams precisely in order to control them and make sense of the data they generate.
"Nobody was building things that can measure, diagnose the beams and help control the accelerator, and also help the experimenters to unravel the data," said Bruce Schumm, the Long Family Professor of Experimental Physics at UC Santa Cruz.
The solution required rethinking the detection system from the ground up. The team combined artificial diamonds, custom microchips, and new assembly techniques into a compact detector. Artificial diamond was chosen for the sensor material because of its ability to handle fast signals at high rates. The electronics required entirely new design as well.
"It required developing a new approach to processing the signal, and also a new integrated circuit chip that we designed ourselves and then characterized," Schumm said. "This is the first time we put it all together and put it into a beam."
That first full test took place last July at SLAC National Accelerator Laboratory in Menlo Park, California, at the Linac Coherent Light Source II. Researchers exposed the detector to electron bursts lasting one picosecond, a unit of time equal to one trillionth of a second. The team collected thousands of beam pulses under varying conditions and found the detector consistently produced clean, sharp results.
Schumm credited the multi-institution structure of the collaboration for making the project possible. "It really highlights the power of collaboration between universities and national laboratories," he said. "If you took away Lawrence Berkeley Lab, if you took away Los Alamos, if you took away UC Davis, any of those, the whole thing would have fallen apart."
The accelerators this system is designed to support are used to study fundamental biological and chemical processes, as well as materials science and energy research. Faster, more precise beam diagnostics allow scientists to run more experiments and extract cleaner data from each one.
