By Josh Perry, Editor
[email protected]

Scientists used the Relativistic Heavy Ion Collider (RHIC) at the U.S. Department of Energy (DOE) Brookhaven National Laboratory (Upton, N.Y.) to demonstrate a novel technique for cooling particle beams using bunches of electrons.

Brookhaven Lab engineer Mathew Paniccia next to the LEReC cooling sections.
(Brookhaven National Laboratory)

According to an article from the lab, this breakthrough will lead to higher particle collision rates at the RHIC and potentially to further understanding of the building blocks of matter that existed shortly after the Big Bang.

“Brookhaven’s accelerator team is testing the method at the collider’s lowest energies—a regime where data has been scarce yet is crucial to understanding how the particles that filled the early universe transformed into the ordinary matter that makes up our world today,” the article explained.

It was the low-energy conditions that made the experiments difficult. Researchers built a state-of-the-art electron accelerator that fit inside the RHIC and used more compact radio frequency (RF) acceleration technology than previous efforts.

“And because RHIC’s ions circulate as periodic bunches of particles, not a continuous stream, the electrons had to be produced in pulses that matched up with those bunches—not just in timing but also in energy and trajectory—all while maintaining their intrinsic coolness,” the article continued. “Plus, because RHIC is really two accelerators, with ion beams moving in opposite directions in two beampipes, the physicists had to figure out how to cool both beams with the same stream of electrons!”

A laser-activated photocathode electron gun that rotated like a wheel to change out photocathodes while the RHIC tunnel was running. There was also a high-powered green laser to activate the photocathodes and it was precisely aligned for the pulses to control the frequency of the electrons being bunched.

“The next step will be to show that the cooling enhances collision rates in next year’s RHIC low-energy collisions—and then extracting the data and what they reveal about the building blocks of matter,” the article said. ‘

Read the full article about this novel cooling technology at https://www.bnl.gov/newsroom/news.php?a=215585.