Scientists at the U.S. Department of Energy's Brookhaven National Laboratory have developed a high-voltage polarized electron gun, marking a significant advancement for the Electron-Ion Collider (EIC) project. This collider, a joint effort with the Thomas Jefferson National Accelerator Facility, aims to accelerate and collide polarized electrons with protons and ions to explore fundamental aspects of visible matter.
"This gun not only exceeds the EIC requirements, but we also get world-leading results," stated Erdong Wang, Brookhaven Lab physicist and chief architect of the device. Wang initiated this project in 2017 and has led its development since then. The research involved collaboration with Stony Brook University and other institutions.
The electron gun will serve as an essential component for one of the EIC's particle streams, accelerating electrons to 80% of the speed of light over a short distance. "We put the 'e' in the EIC," remarked John Skaritka, mechanical engineer at Brookhaven Lab.
The project's success is attributed to its ability to produce electron beams with specific characteristics crucial for scientific investigations at the EIC. Abhay Deshpande, EIC Science Director and professor at SBU, highlighted the collaboration between Brookhaven Lab and Stony Brook in achieving these advancements.
Wang explained that short electron bunches are easily accelerated by radiofrequency cavities, which is vital for effective collisions within the collider. "Having many electrons in a single bunch gives you very high densities," he noted.
The polarization of particles' spins is key to understanding their properties and interactions. By aligning spins in both electron and ion beams, scientists aim to investigate proton spin origins and quark-gluon distributions within protons.
The development process involved creating a unique photocathode structure using gallium arsenide crystals arranged in layers for efficient electron emission. This innovation was supported by collaborators from Old Dominion University and Jefferson Lab.
"Our team includes experts in beam dynamics, high voltage, materials science, lasers, engineering, and beam diagnostics," said Wang.
The research leveraged advancements from Einstein's photoelectric effect theory while pushing boundaries with new materials and technologies. The team addressed challenges such as vacuum environments required for maintaining high voltage without damaging components or emitting greenhouse gases.
"This semiconductor coating is absolutely unique," Skaritka emphasized regarding innovations ensuring safe operation under high voltage conditions.
After extensive testing at Stony Brook University labs, Wang reported stable performance: "This is the highest-voltage and highest-intensity polarized electron gun in the world."
Future efforts focus on further enhancing acceleration stages alongside developing another gun stream intended for cooling ion beams during experiments conducted by DOE Office-funded projects like these cutting-edge initiatives aimed towards deeper insights into fundamental physics principles underlying our universe's structure through groundbreaking discoveries enabled via technological breakthroughs achieved here today!