RAPID CITY, S.D. (Nov. 15, 2012) - School of Mines physicists have played a significant role on the dark matter research team comprised of scientists from the likes of Yale, Brown and Berkeley since the project's beginning three years ago.


The possibility of discovering elusive dark matter and the proximity of the South Dakota School of Mines & Technology to the Sanford Underground Research Facility in Lead, where the experiment will be conducted, is what brought Xinhua Bai, Ph.D., to the university in 2009 from the University of Delaware.

With support from former colleagues in the South Pole Air Shower Experiment (SPASE-2) and Antarctica Muon and Neutrino Array (AMANDA) project, Bai built his own astroparticle physics laboratory from scratch at the School of Mines and formed a team of graduate-level researchers who consider their work with the Large Underground Xenon (LUX) project at the Sanford facility the opportunity of a lifetime.

The LUX tank, 4,850-feet below the earth's surface at Sanford, the old Homestake Gold Mine, has been filled with 70,000 gallons of water. Scientists will begin collecting data in early 2013 in hopes of identifying dark matter. The School of Mines was tasked with calibrating 20 photomultiplier tubes (PMTs), which are installed inside the tank and which researchers hope will help identify the presence of elusive dark matter particles by essentially tagging and eliminating more everyday particles within the Standard Model, a well-established particle physics model that describes the physics of the visible portion of the universe.

For nearly two years, Mines research student Mark Hanhardt calibrated and characterized the 10-inch PMTs in Bai's campus lab while pursuing his master's degree in physics. He earned his M.S. in 2011, and his work on the LUX experiment helped him to land a similar position at the Soudan Underground Lab in Soudan, Minn.

"I cannot describe the joy of working in a field that is both personally interesting and immensely important. Like scientists of the previous age whose discoveries led to the ubiquitousness of electricity, computers or wireless communication - things that have fundamentally changed the entire world - I have the privilege of participating in building the world of tomorrow," Hanhardt said from his new underground research position in Minnesota.

"Working on LUX through SDSM&T has put me in contact with some of the leading scientists in my field, many of whom I continue to work with on other projects in my job at Soudan Underground Lab. It has also given me experience with cryogenic, electrical and analytical systems that is vital to my work as a physicist," Hanhardt said.

Hanhardt grew up in the Black Hills town of Sturgis. His father, Jim Hanhardt, worked at the Homestake Gold Mine until it closed its doors and is now technical support lead at the Sanford Lab. "It was the influence of him and my mom teaching me to always be curious about the next layer of the universe that drove me into physics in the first place. It has been a great treat to get to work with my father at Sanford Lab while I was completing my master's degree and working with LUX," said Mark Hanhardt, who hopes to someday soon return to the School of Mines to pursue a Ph.D. in physics. The proposed doctorate in physics would be the only one offered in the state.

School of Mines researchers, including master's level students Douglas Tiedt and Boris Western, have also developed a muon tagging system for the LUX project. Muon is an elementary particle that exists everywhere on the earth's surface. Deep penetrating, some high-energy muons can break through 4,850 feet of rock and reach Davis Cavern where the LUX detector is located.

The muon tagging system was used in the LUX detector surface run earlier this year to determine how well the LUX detector system works before it was deployed to the underground site, Dr. Bai said. The detector response to muons and other radioactive calibration sources helped scientists verify that the detector works properly.

In addition, Tiedt, who plans to complete his master's degree in spring 2013, helped install Tyvek in the tank the week before it was sealed and began filling with water. He and Daniel Nix, a current undergraduate student in the Mines physics department, have finished a dust characterization system that is designed to measure the inherent charge on dust particles present at the facility, which has been using the LUX cleanroom space on the surface for the past several months. This project is supposed to provide fundamental data to developing a cleanliness plan for the next generation dark matter experiment, LZ.

Like Hanhardt, Tiedt's goal is to pursue his Ph.D. in physics at the School of Mines. The Box Elder native earned his undergraduate degree at the School of Mines.

Western, an Indiana native who earned his bachelor's degree at Purdue University, enrolled at the School of Mines this fall and joined the LUX analysis team recently. His charge is to sift through and interpret collected data. Western enrolled at the School of Mines specifically for the opportunity to work at the underground research facility.

"Working with such brilliant people in search for greater understanding of our universe is exactly what I was hoping for when selecting the School of Mines for graduate studies," Western said.

While the search for dark matter may seem an incomprehensible pursuit, Bai described the LUX project as an uncomplicated "beautiful experiment," which, one way or another, will set records.

"The most unique part is that this detector is the largest one in the world that is running. If we don't see dark matter particles, we will have a new world record in sensitivity for sure. And, if we do see dark matter particles that will really be a breakthrough," Bai said.

Learn more about the LUX dark matter experiment at Sanford Underground Research Facility's website.