Physics is central to understanding the world around us and the universe in which we live. It seeks to answer some of humankind’s most fundamental questions, such as what comprises the universe and how it began.
It is no simple quest.
These questions are so complex that they’re beyond the capabilities of any single person or institution. They require large, unique experimental apparatuses and support facilities — many larger than our own Three Rivers Convention Center. It takes international teams of scientists, engineers and technicians to run these experiments and make sense of the data they gather.
Here at the Department of Energy’s Pacific Northwest National Laboratory, much of our physics research focuses on fundamental scientific discovery and national security. We are part of a large international team hunting for elusive clues in particle physics related to the nature of dark matter. Similarly, we team with other national laboratories and colleagues from allied nations to develop and deploy technology that can detect illicit nuclear weapons development.
Underpinning much of our work is the need for ultra-sensitive nuclear measurements. We design and build specialized detectors made of ultra-pure copper that we “grow” in PNNL’s Shallow Underground Laboratory. This specialized facility allows scientists to analyze samples for minute traces of radioactivity — and to design and develop even more sensitive radiation-detection instruments.
Buried 39 feet underground and covered with another 42 feet of earth to shield against background radioactivity caused by cosmic rays that would interfere with desired measurements, this underground laboratory serves as a test bed where researchers can explore and test methods and techniques. Larger-scale physics experiments are even deeper within mines around the world — including in South Dakota, Minnesota and Ontario, Canada, where PNNL researchers are involved.
PNNL is leading the U.S. contribution to the Belle II experiment, which involves more than 600 researchers from 23 countries. Using a highly specialized particle detector in Japan about the size of a three-story house to conduct research with unprecedented precision, scientists are working to understand why the universe contains matter, but is nearly void of antimatter.
PNNL also provides high-performance computing and data analysis capabilities to Belle II. In the next decade, the project is expected to produce one of the world’s largest scientific data sets, totaling hundreds of petabytes. To put that in perspective, consider that one petabyte of MP3 music files would be enough to play songs continuously for over 2,000 years.
Just last month, collaborators from PNNL and five other institutions were the first in the world to detect something called cyclotron radiation from individual electrons.
Cyclotron radiation is given off by electrons whirling around in a circle while trapped in a magnetic field. Using a specially developed method, these researchers were able to measure the energy of electrons, one electron at a time.
Why does research like this matter? The common theme in these fundamental searches for undiscovered particle properties is watching for rare events that give evidence of new physics.
For example, being able to detect cyclotron radiation may provide a new way to measure the mass of the neutrino. Neutrinos are tiny subatomic particles so small that today they cannot be weighed individually. However, all the neutrinos in the universe together weigh more than all other matter in the universe (like stars, planets and dust) and can affect the formation of large-scale structures like galaxy clusters. Studies like these will help us understand the origins of the universe.
The significance of applied high-energy physics research may be easier to grasp, like the need to develop tools to detect underground nuclear explosions and trafficking of illicit nuclear materials. Some of our research aims to improve the trace measurements of background radiation that can be taken as a baseline so that the tiny differences in these measurements could be detected when and if a nuclear explosion took place. The same detection capabilities helped the U.S. and Japanese governments understand the immediate aftermath of the Fukushima disaster.
Beyond PNNL, the National Science Foundation’s LIGO, or the Laser Interferometer Gravitational-Wave Observatory, also is right here in Richland. LIGO’s mission is to observe gravitational waves of cosmic origin. Some of its research aims to unravel mysteries surrounding the formation of black holes and the birth of the universe.
Later this month, I look forward to helping celebrate the installation of advanced gravitational wave detectors at LIGO. The new instruments will enable even more advanced research because they are more sensitive and significantly increase the volume of space that LIGO will survey.
The researchers engaged in these exacting experiments share a passion for knowledge. They are trying to answer questions that may lead to even more challenging questions. Or they may find answers that are at the heart of discoveries that could change our lives or the lives of future generations. Either way, this extraordinary science is happening all around the world — and right here in the Tri-Cities.