Lab technician Rashyll Leonard completes connections for collecting radon from the LUX experiment underground at SURF during decommissioning, September 20, 2016. Photo credit: Dr. Eric Miller.
RAPID CITY, SD (Feb. 17, 2017) – The LUX-ZEPLIN (LZ) dark matter detector in the Sanford Underground Research Facility (SURF) in Lead has reached a major milestone. U.S. Department of Energy approval for the final design of the LZ experiment launches the construction phase and pushes the project toward the completion goal of April, 2020. Next-gen dark matter detectors have become sensitive enough that researchers around the world are now more confidently racing to be the first to directly observe the existence of dark matter particles. LZ is in direct competition with two projects in Italy and China. Researchers at South Dakota School of Mines &Technology are playing a key role in the detection and removal of radon from the sensitive equipment to ensure LZ has the cleanest signal possible.
“Physicists at Mines are playing a role in one of the most exciting physics experiments in the world,” said SD Mines President Heather Wilson.
LZ is being placed almost a mile underground to reduce the impact of cosmic rays that can hide the potential dark matter signal. But other types of background radiation and contamination can also produce false signals and hurt the effort to detect dark matter. Researchers must painstakingly measure all components of LZ for naturally occurring radiation. One challenge is the removal of radon, a naturally occurring radioactive gas that could interfere with dark matter detection.
Mines physics professors Richard Schnee, Juergen Reichenbacher and Xinhua Bai, Ph.Ds., are leading research on planning an underground radon-removal system and on testing whether plans to keep LZ materials free of dust and radon daughters are working properly. Reichenbacher operates a new device that can measure small amounts of radon daughters on the surface of materials without having to break the materials. “It’s a million times more sensitive than the standard swipe tests performed in airports,” said Reichenbacher.
The group also leads the measurement of how much radon is produced from LZ materials. “If a material produces too much radon, it can’t be used in the experiment, and our collaborators will have to find a new material to do the job,” said Schnee.
SD Mines researchers play one part in the overall effort. The total LZ collaboration consists of 250 scientists and engineers from 37 institutions in the U.S., U.K., Portugal, Russia and Korea.