Straws, crystals and the quest for new subatomic physics

Several of the Mu2e tracker planes, featuring thin mylar straws, are assembled in a cleanroom at Fermilab. The full tracker will contain 21,600 straws to measure the paths, energies and momentums of electrons with high precision.
Photo: Ryan Postel, Fermilab

Scientists build complex machines to better understand the particles that make up our universe — and sometimes, they use materials you might not expect. One example? The upcoming Mu2e experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory will incorporate thousands of straws made by a drinking straw company.

But these aren’t your average soda straws. Mu2e will use special mylar straws, with walls thinner than a human hair, to search for a never-before-seen transformation of subatomic particles called muons.

Teams from this international collaboration are currently constructing the Mu2e particle detector at Fermilab and aim to start taking physics data by 2026. If they find the rare, sought-after signal, it will be a sign of new physics beyond the tried and tested Standard Model of particle physics. It would help pave the way to answer open questions about the fundamental nature of elementary particles and forces that physicists have had for many years.

The wild years of our Milky Way galaxy

The architectural galaxy: our Milky Way consists of different components. Max Planck researchers have now reconstructed the history of thick and thin discs in particular.
Credit: Stefan Payne-Wardenaar / MPIA

A very long time ago, our Milky Way had a truly eventful life: between about 13 and 8 billion years ago, it lived hard and fast, merging with other galaxies and consuming a lot of hydrogen to form stars. With the help of a new data set, Maosheng Xiang and Hans-Walter Rix from the Max Planck Institute for Astronomy in Heidelberg have reconstructed the turbulent teenage years of our home galaxy. To do this, the researchers had to precisely determine the ages of 250,000 Milky Way stars.

Understanding the formation history and evolution of our home galaxy is a major goal for astronomy and astrophysics, and one where a flood of high-quality “big data” over the past years has led to impressive progress. The new study by Xiang and Rix constitutes a big step forward by putting much more precise dates onto the different phases of early Milky Way history. This was made possible by a unique analysis that managed to determine the ages of 250,000 stars.

A rough sketch of Milky Way history

In our current understanding, our home galaxy went through several phases. During the “baby phase” (not an official astronomy term), small, gas-rich progenitor galaxies merged to form a conglomerate that subsequently grew into our Milky Way. As those galaxies did not collide head-on, they imparted a spin on the resulting structure, presumably flattening its out into what we now see as the so-called thick disk of our Milky Way: gas and stars in a flat pancake, 100,000 light-years in diameter and 6000 light-years thick.

New X-Ray Technique Provides Novel Images of Triso Nuclear Fuel

Credit: Idaho National Laboratory

Advanced nuclear technologies could play an important role for nations seeking carbon-free energy solutions to reduce the impacts of climate change.

Companies around the world are developing advanced reactor designs to meet a range of needs, from microreactors for remote applications to large reactors that could power huge urban areas while also providing heat for industrial applications such as hydrogen production.

While these advanced reactors are a diverse bunch, they all benefit from both passive and inherent safety design features that use advanced materials to increase safety, reliability and performance.

One type of inherently safe technology, TRi-structural ISOtropic particle fuel (TRISO), consists of a kernel of uranium-based fuel surrounded by three layers of carbon- and ceramic-based materials chemically and structurally resistant to degradation in a reactor environment.

The resulting fuel particle is roughly the size of a poppy seed and can withstand temperatures of more than 3,000 degrees Fahrenheit, well beyond the threshold of current nuclear fuels, without melting or releasing significant quantities of fission products.

Research Says Docile Gecko is a Savage Scorpion Predator

SDSU researchers document geckos violently shaking from side to side to immobilize their scorpion prey.

When western banded geckos are hungry, they pounce on crickets, beetles, or other small arthropods in their environment, and quickly gobble them up.

But when they catch scorpions, they begin to shake themselves violently from side to side at high speeds, smashing their prey back and forth against the ground for several seconds until it is immobilized. After the fracas, the gecko devours the much smaller scorpion.

“It's a really kind of physically stunning behavior, something totally unexpected from a lizard like that,” said San Diego State University biologist Rulon Clark.

“They seem to be kind of body slamming the scorpions into the ground. If you ever see seals, they'll pick fish up and they'll slap them against the water. I think geckos are doing essentially the same thing, just blunt force trauma.” said Malachi Whitford (‘20), who studied the geckos’ unusual feeding behavior as a graduate student in the joint SDSU and University of California, Davis Ph.D. program in ecology. The University of California, Riverside, also participated in the research.

On Icy Enceladus, Expansion Cracks Let Inner Ocean Boil Out

Saturn's tiny, frozen moon Enceladus is slashed by four straight, parallel fissures or "tiger stripes" from which water erupts. These features are unlike anything else in the solar system. Researchers now have an explanation for them.
NASA/JPL/Space Science Institute image

In 2006, the Cassini spacecraft recorded geyser curtains shooting forth from “tiger stripe” fissures near the south pole of Saturn’s moon Enceladus — sometimes as much as 200 kilograms of water per second. A new study suggests how expanding ice during millennia-long cooling cycles could sometimes crack the moon’s icy shell and let its inner ocean out, providing a possible explanation for the geysers.

Enceladus has a diameter of about 504 kilometers (313 miles) — roughly the length of the United Kingdom at its longest point. The moon is covered in ice 20-30 kilometers (12.4-18.6 miles) thick, and the surface temperature is about -201 Celsius (-330 Fahrenheit), but a decade of data from NASA’s Cassini–Huygens mission supplied evidence for a deep liquid ocean inside the icy shell, escaping into space through continuous “cryo-volcanism”. How such a small, cold world can sustain so much geological activity has been an enduring scientific puzzle.

“It captivated both the scientists’ and the general public’s attention,” said Max Rudolph, an assistant professor in geophysics at the University of California, Davis, and lead author of the new study, published in Geophysical Research Letters.

New study of Yellowstone National Park shines new light on once hidden details of the famous American landmark

The SkyTEM instrument being flown over Old Faithful in Yellowstone National Park.
Photo by Jeff Hungerford, Yellowstone National Park; supplied by Carol Finn of U.S. Geological Survey.

The geysers and fumaroles of Yellowstone National Park are among the most iconic and popular geological features on our planet. Each year, millions of visitors travel to the park to marvel at the towering eruptions of Old Faithful, the bubbling mud cauldrons of Artists Paint Pots, the crystal-clear water and iridescent colors of Grand Prismatic Spring, and the stacked travertine terraces of Mammoth Hot Springs.

Those who have visited the park may have asked themselves, “Where does all the hot water come from?” A study published this week in Nature, co-authored by Virginia Tech’s W. Steven Holbrook and colleagues from the U.S. Geological Survey and Aarhus University in Denmark, provides stunning subsurface images that begin to answer that question.

The research team used geophysical data collected from a helicopter to create images of Yellowstone’s subsurface “plumbing” system. The method detects features with unusual electrical and magnetic properties indicative of hydrothermal alteration.

Quan­tum sen­sors: Mea­suring even more preci­sely

Time could be determined even more precisely with sophisticated computational methods on entangled atoms. Physicists from Innsbruck, Austria, have developed such a technique.
Credit: Uni Innsbruck/Harald Ritsch

Two teams of physicists led by Peter Zoller and Thomas Monz have designed the first programmable quantum sensor, and tested it in the laboratory. To do so they applied techniques from quantum information processing to a measurement problem. The innovative method promises quantum sensors whose precision reaches close to the limit set by the laws of nature.

Atomic clocks are the best sensors mankind has ever built. Today, they can be found in national standards institutes or satellites of navigation systems. Scientists all over the world are working to further optimize the precision of these clocks. Now, a research group led by Peter Zoller, a theorist from Innsbruck, Austria, has developed a new concept that can be used to operate sensors with even greater precision irrespective of which technical platform is used to make the sensor. “We answer the question of how precise a sensor can be with existing control capabilities, and give a recipe for how this can be achieved,” explain Denis Vasilyev and Raphael Kaubrügger from Peter Zoller's group at the Institute of Quantum Optics and Quantum Information at the Austrian Academy of Sciences in Innsbruck.

Dense Bones Allowed Spinosaurus to Hunt Underwater

Dense bones in the skeleton of Spinosaurus strongly suggest it spent a substantial amount of time submerged in the water.
Artwork credit: Davide Bonadonna

Spinosaurus is the largest predatory dinosaur known – over two meters longer than the longest Tyrannosaurus rex – but the way it hunted has been a subject of debate for decades.

In a new paper, published today in Nature, a group of paleontologists have taken a different approach to decipher the lifestyle of long-extinct creatures: examining the density of their bones.

By analyzing the density of Spinosaurid bones and comparing them to other animals like penguins, hippos, and alligators, the team found that Spinosaurus and its close relative Baryonyx from the Cretaceous of the UK both had dense bones that would have allowed them to submerge themselves underwater to hunt.

Scientists already knew that Spinosaurids had certain affinities with water – their elongate jaws and cone-shaped teeth are similar to those of fish-eating predators, and the ribcage of Baryonyx, from Surrey, even contained half-digested fish scales.

Undersea sediment reveals clues about seismic activity

The Chikyu is capable of drilling deeper below the seafloor than any other science drilling vessel to date.
Credit: Sean Toczko (JAMSTEC staff scientist) ECORD/IODP/JAMSTEC.

Earthquakes are famously impossible to predict, and have been the cause of some of the most devastating events in human history. But could we learn more about these natural disasters by tracking them backwards through time?

One research mission, dubbed Expedition 386, wants to use sediment records in the Pacific Ocean off the coast of Japan to track and record thousands of years of past seismic activity.

Although the offshore portion of the expedition ended last summer, the scientific portion of the mission, a month-long investigation into the recovered samples, recently ended on March 15.

Roughly 30 international scientists are involved with the project, including Derek Sawyer, an associate professor of earth sciences at The Ohio State University.

A Laser-Powered Upgrade to Cancer Treatment

Kei Nakamura, Antoine Snijders and Lieselotte Obst-Huebl (from left) at the BELLA laser facility aligning cartridges containing human cells in the proton beam path. This setup enabled measurements of the biological effects of laser-driven protons.
Credit: Lawrence Berkeley National Laboratory

Biologists and physicists at Lawrence Berkeley National Laboratory (Berkeley Lab) have teamed up to create new opportunities for cancer treatment using laser-generated proton beams.

The ongoing project seeks to adapt the nascent technology of laser-driven ion accelerators – which are as cool as they sound – to make a more effective type of radiation therapy more readily available to patients.

“Proton therapy centers are large, expensive facilities, so they are limited around the world,” said co-lead author Antoine Snijders, a cancer researcher and senior scientist in the Biological Sciences and Engineering (BSE) Division. “There is currently limited geographic distribution and access to proton therapy worldwide.  The way to get broader access, and potentially lower costs, is to reduce the cost and footprint of these types of facilities. And that means we need more compact sources of ions for proton accelerators.”

Scientists are also investigating the potential benefit of using these accelerators to deliver proton beam radiation therapy at ultrahigh doses within extremely short exposure times – a technology called FLASH radiotherapy. Though the approach remains experimental for now, FLASH radiotherapy could change the landscape of radiation oncology. “If our work could also bring FLASH radiotherapy to patients, it could be the best of both worlds,” Snijders added.