Almost a mile beneath the surface of the Earth, experiments are taking place which could further unlock the mysteries of the universe – and junior Iseley Marshall is right in the thick of it.
More than two years have passed since the National Science Foundation gave its nod of approval to turn South Dakota’s Homestake gold mine into the world’s deepest underground laboratory.
Recently, experiments have yielded results which sent Marshall, along with five other students and faculty, to Hawaii to present their findings to a joint conference between the American Physical Society-Department of Nuclear Physics and the Physical Society of Japan.
At the conference, attended by more than 600 scientists, the USD contingent presented six papers and two posters ranging from background characterization of the site and new methods of dark matter detection. Dark matter is a theoretical substance which has yet to be detected, but its effect on visible matter can be measured.
“We know it’s out there because of its effect on the way stars and galaxies move,” said Tina Keller College of Arts and Sciences associate dean. “So what you would like is to actually have a detector that gives a signal that says, ‘Oh that must be dark matter.’”
Although USD’s physics department has made forward progress, much work has to be done within the Homestake mine, measuring background radiation and developing methods to detect dark matter.
From a physics standpoint, there are two major avenues of research that will be done at the lab, Keller said. The first is the nature of the neutrino and neutrinoless double-beta decay, the second is the detection of dark matter.
Marshall worked during the summer developing a shielding apparatus to contain samples in a radiation-free zone, to determine what amount and type of radiation they project.
The radiation Marshall is working to eliminate is not the radiation commonly associated with nuclear blasts — it comes from cosmic rays. The crux of the problem is the matter they are trying to detect – dark matter – has an extremely weak “ping” and in order to see it; all of the background noise has to be eliminated.
Marshall’s hope is for the shield to block out all of the background noise, so samples of materials in the mine have a measurable noise. The data on background levels would then be made available to other researchers.
“The scientists who go down there (for) all of these experiments are going to need data on radiation in the mine,” Marshall said.
Marshall began her physics research last spring, but only started her shielding work after classes let out.
“Over the summer (is) when they took us onboard for summer research. They needed a shield for a high purity germanium detector,” Marshall said.
Junior Brian Woltman also spent his summer at USD working on a voltage divider; a device which is used in conjunction with a larger project to detect dark matter, a theoretical substance which some physicists believe constitutes the majority of matter in the universe.
Keller said she has not seen a spike in declared physics majors since the incorporation of deep underground research, but said the opportunities for research make this a “great time to get involved in physics.”
Keller added that just being in the same state as the deep underground lab itself does not imply any heightened status, but that doing good work with the lab “does raise the profile of the institution within the physics community.”
While the physics department may not have seen a bump in physics majors, it has seen the addition of new faculty, and attracting researchers like Dong Ming Mei, an assistant professor who came to USD from Los Alamos National Laboratory in 2003.
“Both Dr. Mei and Dr. Guiseppe, I really think came to USD because they knew that a deep underground science and engineering lab was happening in the western side of the state,” Keller said.
Mei has his name on more than $4.4 million in research grants relating to the Deep Underground Science and Engineering Laboratory project, which is 97 percent of all grant money in the Earth Science/Physics department.
“Our physics department is small compared to other places, but there is funding and room for us to grow,” Marshall said. “I really think this will help out our school a lot.”
Reach reporter Nolan Peterson at Nolan.H.Peterson@usd.edu.
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