Fermilab Today

Energy.gov profiles women who work in science, technology, engineering or math in an online feature called Women @ Energy. This year's profiles include members of Fermilab staff.

Women @ Energy showcases some of the talented and dedicated employees from across the DOE complex who share what inspired them to work in STEM, what excites them about their work at the Department of Energy and their ideas for engaging more underrepresented groups in STEM.

In Brief

Now accepting nominations for the Fermilab Student and Postdoc Association

The Fermilab Student and Postdoc Association is calling for nominations for next year's FSPA officers.

If you are a young researcher at the lab and want to give something back to the community, consider nominating yourself or someone you know. This is a great opportunity to see how the lab is run, to have a chance to meet your congressional representatives in Washington, D.C., and to organize activities with your fellow students.

The nomination period closes at 11:59 p.m. on Monday, Sept. 21. Candidates will be announced and voting will begin shortly thereafter.

Send nominations and questions directly to fspa_officers@fnal.gov.

Photo of the Day

Spider by the meter

A spider hangs out during a recent gas meter reading at Site 39. Photo: Al Wywialowski, FESS

In the News

How to see the universe through neutrino eyes

From Scientific American, Sept. 15, 2015

Buried a mile into the South Pole ice, more than 5,000 sensors spread over a square kilometer lie in wait. Part of the IceCube experiment, they are a telescope of sorts that looks not for light, but for neutrinos coming in from the far-off cosmos.

Neutrinos are fundamental particles with no electric charge and almost negligible mass. Because of these properties, they are immune to the electromagnetic force and feel gravity only very minutely, and so they rarely interact with other matter. That property allows them to fly through space — even through Earth and our bodies — without impediment. But very rarely, one will hit an atom of polar ice head-on and release a spray of other particles, which in turn emit photons that light up IceCube's sensors. If one struck an atom in your body (which should happen at least once in a lifetime to about a quarter of all people, one physicist estimates), you wouldn't notice, but a similar reaction would occur.

From symmetry

XMASS continues dark matter debate

XMASS is the latest of multiple experiments to contradict a previous dark matter discovery claim, but the conversation isn't over yet. Photo courtesy of Kamioka Observatory, ICRR, The University of Tokyo

Since 1998, scientists on the DAMA-LIBRA experiment at Gran Sasso National Laboratory in Italy have claimed the discovery of an increasingly statistically significant sign of dark matter.

This week, the XMASS experiment in Japan joined the LUX, Xenon100 and CDMS experiments in reporting results that seem to contradict that claim.

Scientists look for dark matter in many ways. Both this result from the XMASS experiment and the results from DAMA-LIBRA look for something called annual modulation, a sign that the Earth is constantly moving through a halo of dark matter particles.

As the sun rotates around the center of the Milky Way, the Earth moves around the sun, completing one revolution per year. During the first half of the year, the Earth moves in the same direction as the sun; during the second half, the Earth completes its circle, moving in the opposite direction.

When the sun and Earth are moving in the same direction, the Earth should move through slightly more dark matter than when the sun and Earth are moving in opposite directions. So scientists should see a few more dark matter particles hit their detectors during that part of the year.

Experiments other than DAMA-LIBRA have seen hints of an annual modulation, but only the CoGeNT experiment has ever provided support for DAMA-LIBRA's claim that this modulation comes from dark matter.

The effect could be caused by other annual changes. Pressure and temperature could affect an experiment. Atmospheric changes with the seasons could affect the number of cosmic rays that reach the experiment. Background radiation from radon gas has been known to change seasonally for underground experiments because of its interaction with the water table in the rock, says Fermilab scientist Dan Bauer of the CDMS experiment.

"Nobody's been able to put their finger on what's causing the DAMA modulation," he says. "We can't find the smoking gun."

—Kathryn Jepsen

In the News

How neutrinos saved your teeth from cavities

From Science, Sept. 11, 2015

Every second, trillions of neutrinos born at the center of the sun shoot through your body. They don't hurt you, because these ghostly elementary particles almost never interact with matter. But astronomers report that nonetheless neutrinos forged much of the universe's fluorine, an element added to toothpaste and water to fight cavities and whose cosmic origin has long been mysterious.

In one way or another, stars created most of the chemical elements. With an atomic number of nine, fluorine sits between oxygen and neon on the periodic table but is much rarer than either. A massive star creates huge amounts of oxygen and neon during its life and then hurls them into space when it explodes, so both elements are common: Oxygen is the third most abundant element in the universe, after hydrogen and helium, and neon ranks fifth or sixth. In contrast, fluorine is so rare it doesn't even make the top 20.

Two astronomers — Catherine Pilachowski of Indiana University, Bloomington, and Cameron Pace of Southern Utah University in Cedar City — went looking for it. Using the 2.1-meter telescope atop Kitt Peak in Arizona, they searched 79 stars for a nasty gas named hydrogen fluoride (HF), which contains the element. "Terrible stuff," Pilachowski says. Breathing the gas can be fatal. But it absorbs infrared radiation and thus can leave a mark on a star's spectrum that the astronomers hoped to see.