Recently, the Department of Energy’s Pacific Northwest National Laboratory (PNNL) researchers, helped shed light on the possible existence of dark matter – called “dark” because it is invisible to today’s telescopes – that may be responsible for gravitational effects that can be detected but not explained by the matter we can observe.
PNNL scientists apply their expertise in physics, chemistry, materials science and engineering to advance our understanding of nuclear and particle physics. Their research delves deep into questions about the universe and its origin, its unseen building blocks, and how the forces within it work together.
The existence of dark matter and its resulting gravitational effects would help to explain how galaxies formed. Scientists are convinced that dark matter far outweighs observable matter in the universe, but there is still much they do not know.
Theories predict that dark matter is composed of fundamental sub-atomic particles that have yet to be discovered, including one dubbed the “axion.” Last month, a large international collaboration of scientists announced the creation of an ultra-sensitive device that can “hear” the telltale signs of dark matter axions while tuning out the electromagnetic “noise” that makes them difficult to detect.
In this project, PNNL used its state-of-the-art microwave engineering and modeling expertise to help design a highly sensitive microwave receiver that “listens” for and identifies the weak axion signal. This same capability underpins the millimeter-wave security scanners used to screen passengers at airports.
In a different collaboration, PNNL is involved in another of the world’s most sensitive dark matter experiments. This one will search for a different class of theorized dark matter particles called weakly interacting massive particles, or WIMPs. Rather than “listening” for these particles, this project seeks to measure WIMP dark matter with a highly sensitive radiation detector.
PNNL researchers are helping to design this detector, which must be made of materials with ultra-low levels of naturally occurring radioactivity so as not to interfere with the measurements they seek.