Studying stars from underground
All chemical elements, except hydrogen and helium, were created over the course of billions of years by nuclear reactions in the hot interiors of remote and long-vanished stars. Although scientists understand the recipe of how stars work, they don't know the full range of astronomical phenomena that occur. The Compact Accelerator System Performing Astrophysical Research (CASPAR) aims to change that.
"This project could help complete our picture about the mechanisms that generate energies in stars and how the elements in our universe are built," said Dr. Frank Strieder, Principal Investigator for the project. The accelerator will help researchers mimic nuclear fusion in stars.
"There is a famous saying, 'We are all stardust.' So we need to have a better understanding of what happens in stars." That means going deep underground, Strieder said, and Sanford Lab is the perfect place. "The infrastructure is in place and we escape cosmic radiation."
Over the past year, Syd DeVries has been managing the design of CASPAR utilities on the 4850 Level. With ground support complete, construction crews are ready to begin installing the utilities needed to operate the experiment/electrical service, heating and air conditioning, and life safety systems.
"We want CASPAR researchers to have the right space in which to operate their experiment," said DeVries, who is the Underground Construction Manager at Lawrence Berkeley National Laboratory (LBNL).
Experiments go underground to escape cosmic radiation. But everything around us contains some level of radioactivity, including rock and the materials used in construction. CASPAR is further protected from radiation with a unique design: Walls at the entrance and exit to the experiment are two feet thick. Additionally, the doors are lined with lead to mitigate any stray neutrons from traveling outside of the experiment.
DeVries expects the construction will be completed in August. In the meantime, members of the CASPAR team are preparing the equipment and renovating the accelerator at Notre Dame. When construction is complete, CASPAR researchers will begin moving into the cavern. Strieder said the experiment will be operational by January.
Strieder worked for several years with the LUNA (Laboratory for Underground Nuclear Astrophysics) project at Gran Sasso Laboratory in Italy. LUNA was the first underground accelerator to look for nuclear fusion in stars. Now an Associate Professor of Physics at the South Dakota School of Mines & Technology, Strieder said he is excited about coming to the CASPAR experiment where he can continue that research.