Science Goes
Underground
Imagine something so small and so weakly interacting that 100 billion of
them go through your thumbnail per second and you don’t even know it.
Difficult – perhaps impossible – to imagine for most of us.
Now try to imagine a 30-ton device that despite its size still
sees only a few per day of this tiny, weak matter. Again, a
concept beyond the scope of human comprehension.
But that’s what physics is all about — exploring and
theorizing about the “incomprehensibles” that make up
our world. And for physicists in the College of Science at
Virginia Tech, some of these explorations are taking place
underground … literally.
Kimballton Mine
The particles referred to above are called neutrinos, and
they originate from the center of the sun. Neutrinos are
one of the fundamental particles of the universe but also
one of the least understood. They differ from electrons
in that they do not carry an electric charge and can pass
through great distances in matter without being affected
by it.
secondary background. So the deeper you go, the more
you attenuate these muons, and the less background you
have. In physics, the name of the game is to get rid of that
background or the activity produced by it so you can see
rare events of interest.”
Studying neutrinos this way helps us understand the sun
and stars and even the deep core of our Earth. But this
“low-background counting” technology also provides
the capability to detect extremely small trace amounts of
radioactivity contained in samples of material, resulting in
applications for homeland security, microelectronics, and
space science.
Other Research
But it’s not only physics that has taken an interest in Kimballton for scientific experimentation. Certain types of
research in geosciences, microbiology, and engineering
The Kimballton facility, a joint project between Virginia
Tech and the Naval Research Laboratory, is being
constructed 1,700 feet below ground at an operating
limestone mine in Giles County, Va. (about 20 minutes
northwest of Blacksburg). The facility will house research
related to detecting and measuring low-energy neutrinos
and their properties.
“In a normal university lab, we can do
experiments that we measure in sizes
of centimeters and meters and in
durations of minutes and hours,”
said Robert Bodnar, University
Distinguished Professor of Geosciences. “But it’s difficult to ‘scale’
these processes up to the real world
and estimate changes, such as those
in geological formations, that may
occur over the course of hundreds to
thousands of years and may occur at
spatial scales of kilometers to tens of
kilometers. By setting up experiments
underground that can run for years
or decades, we can get a much better
idea of how things behave on longerterm scales.”
Bodnar said an underground environment also reduces the risk of environmental interferences that can hinder
long-term experiments above ground.
The Kimballton site is also desirable
to a number of scientific disciplines
because of its location in sedimentary
rock – an environment where a wide
variety of processes occur in nature.
“For example, 90 percent of groundwater comes from sedimentary rock,”
Bodnar said. “All petroleum deposits
we produce are from sedimentary
rock; the majority of underground
mines in the United States are in
sedimentary rock. So there is a wide
breadth of research opportunities
Why underground? Simply put, to shield detectors from
cosmic ray backgrounds.
“Cosmic ray protons and neutrons are quickly attenuated
as you get deeper under the Earth’s surface,” said Bruce
Vogelaar, professor of physics, who is leading the project.
“But muons (a heavier version of an electron) continue
to penetrate much deeper, and when they pass through a
detector, can produce background events themselves or
can also benefit from an underground
location. For example, researchers
in geosciences are attracted to the
capability to conduct research related
to scales of time and space.
there.”
From left Bruce Vogelaar, Robert Bodnar and mine manager
Ray Roeder outside the entrance to Kimballton.
Photo courtesy of Bruce Vogelaar
Another example of the diversity of
research efforts that benefit from
experimentation within the confines of
a mine is the university’s AMADEUS
(Adaptive Real-Time Geological Map-
ping Analysis of Underground Space)
project. A multidisciplinary effort
among faculty from civil and environmental engineering, mining and
minerals engineering, and computer
science, this NSF-funded project focuses on mining safety and geological
stability issues through the use of
computer modeling.
The development of life can also be
explored by looking at organisms
buried hundreds of millions of years
ago, and members of Virginia Tech’s
Virginia Bioinformatics Institute are
looking at the impact ancient waterrecharge may h