LEAD — Once known as the DUSEL team, officials involved with planning efforts to build an underground science facility in Lead are now referring to the project as SURF — Sanford Underground Research Facility.
Kevin Lesko, the University of California-Berkeley physicist who is leading the charge to build the federally funded science facility at the former Homestake Gold Mine, said the change started last December, when the National Science Board decided the Department of Energy should assume a leadership role in building the facility. When that happened, what was once planned as an $875 million project that could immediately house multiple physics, biology, geology and engineering experiments at three different main campuses, started to become a smaller facility that was tailored to the Department of Energy's physics priorities, at least initially. Those priorities include physics experiments in dark matter, double beta decay and long baseline neutrino research.
Lesko said the scaled back plans boil down to just one underground research campus. Originally, lab officials planned to build a major surface campus, a science campus 4,850 feet underground that included two lab modules, and a smaller lab module campus 7,400 feet underground. The Sanford Underground Research Facility, Lesko said, focuses on building just one campus at the 4,850-foot level that will host experiments in dark matter, double beta decay, and long baseline neutrino research. Plans also call for room to grow in the future, developing even more science at the facility as funding allows.
“This was a major change. This stewardship model going from the NSF to the DOE was rather abrupt and so we wanted to give them a reasonable and safe, but cost effective option,” Lesko said about the changes. “It did result in a substantially reduced facility, but it is a facility that has all the potential to be expanded, adapted, and modified as required by the science. So we're not set forever at this particular scale. But this is the right scale to approach these three problems that the Department of Energy is particularly interested in.”
The scale change will result in substantial cost savings for the infrastructure of the facility, with facility cost estimates going from a total investment of $575 million in the preliminary design to between $140 million to $160 million for facility construction to support the dark matter and double beta decay experiments. That is above the investment needed for the long baseline neutrino experiment, LBNE.
“The shift in leadership from the NSF to the DOE resulted in our having to change the accounting for the infrastructure. To be fair, DOE's Long Baseline Neutrino Experiment will be responsible for a larger share of the infrastructure at Homestake than under the NSF model. Separating the accounting out is complicated, making comparisons difficult. It involved commitments from both agencies. We developed an entire presentation to help the review committees understand how to translate between the two models.” Lesko said.
Total cost estimates for the long baseline neutrino experiment, which include both infrastructure in Homestake and some upgrades at Fermilab in Illinois, are at approximately $1 billion to $1.5 billion.
Lesko said his team is very optimistic that this change will help the facility construction move forward in a timely manner. The Department of Energy, Lesko said, has indicated that it will decide how to proceed with the project before the end of this year. A report that the Department of Energy requested from the National Research Council, which objectively addresses the necessity of underground research in an international context, along with an assessment of underground research facility options from the Marx Committee, which the Department of Energy also assembled, will weigh heavy on the DOE's decision. Both reports indicate that underground science in dark matter, long baseline neutrino research, and double beta decay are critical for today's changing times, and that it is very important for the U.S. to take a leadership role in this research. Lesko remains hopeful that NSF will remain engaged in these exciting research opportunities as they advance the DOE facility design.
“It was very important that we had an objective look at the science in an international context that analyzed the importance of that science to the U.S.,” Lesko said. “We have always felt that these were very exciting, transformational experiments, but now we have an independent assessment by world-renowned scientists and engineers. That was very important for us to get this independent assessment and to validate that our excitement to do this is aligned with the most critical science goals.”
But as planning moves forward, Lesko said it is important that people understand the name change that distinguishes the project from the NSF's former goals, to those DOE goals of today. The acronym DUSEL (Deep Underground Science and Engineering Laboratory), he said, was associated with the National Science Foundation's efforts.
“The Department of Energy is not interested in a stand-alone, national lab,” Lesko said. “They're interested in a facility to do their science. We're using that terminology of underground research facility to distinguish our planning process now from DUSEL, so people don't assume we are doing the $875 million facility that we had once talked about.”