Scientific snapshots from Berkeley Lab

A machine learning solution for designing materials with desired optical properties

The Berkeley Lab researchers’ method can also quickly calculate the optical properties of most materials

By Julie Chao

Understanding how matter interacts with light – its optical properties – is critical in a myriad of energy and biomedical technologies, such as targeted drug delivery, quantum dots, fuel combustion and biomass cracking. But the computation of these properties is computationally intense and the inverse problem – designing a structure with the desired optical properties – is even more difficult.

Now scientists at the Berkeley Lab have developed a machine learning model that can be used for both problems: calculating the optical properties of a known structure and, conversely, designing a structure with the desired optical properties. Their study was published in Cell Reports Physical Science.

“Our model behaves bidirectionally with high accuracy and its interpretation qualitatively retrieves the physics of how metallic and dielectric materials interact with light,” said corresponding author Sean Lubner.

Lubner notes that understanding radiative properties (which includes optical properties) is just as important in the natural world for calculating the impact of aerosols like black carbon on climate change.

The machine learning model proposed in this study was trained on spectral emissivity data from nearly 16,000 particles of various shapes and materials that can be experimentally fabricated.

“Our machine learning model accelerates the reverse design process by at least two to three orders of magnitude over the traditional reverse design method,” said co-author Ravi Prasher, who is also Berkeley Lab’s Associate Director for Energy Technologies.

Mahmoud Elzouka, Charles Yang and Adrian Albert, all scientists in the Energy Technologies area of ​​Berkeley Lab, were also co-authors.

A new data milestone for the CUORE experiment in Italy

HEART collects a record volume of data for an experiment using solid crystals to search for an ultrarare process

By Glenn Roberts Jr.

Surrounded by lead and also shielded by nearly a mile of rock from the natural bombardment of particles on the Earth’s surface, the CUORE experiment has amassed the largest data set so far for a project of its kind, which uses solid crystals to detect a theorized event. which would answer a big question about how matter won over antimatter in our universe. It would also tell us whether the spectral particles called neutrinos, which pass through most matter without interruption, are essentially their own antiparticles.

Data collected by CUORE, the Cryogenic Underground Observatory for Rare Events, now represents more than a “ton-year” of data (equivalent to one year of data if crystals weighed a ton) collected by a. liquid or gas) for an experiment of its kind, based on the weight of its detector’s crystals. CUORE has an array of 988 crystal detectors. Its crystals each weigh around 1.6 pounds and in total weigh around 0.8 tons.

Located at the Gran Sasso National Laboratory (Gran Sasso National Laboratories, or LNGS, managed by the Italian Institute of Nuclear Physics, INFN) in central Italy, CUORE has reached a milestone in exceeding the data collected for experiments by about 10 times comparables, said Yury Kolomensky, a US spokesperson for the CUORE collaboration and senior scientist at the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

The experiment is designed to detect a theorized and never before seen nuclear decay process known as neutrino-free double beta decay, which occurs in atoms of tellurium-130, a radioactive isotope in detector crystals. An isotope is a form of an element with more or fewer neutrons (discharged particles) in its core than the standard.

CUORE has been conducting its ultra-sensitive research continuously since March 19. It works near absolute zero, the coldest temperature in the known universe. The CUORE collaboration plans to run the experiment for another few years, then upgrade it to CUPID, a new, even more sensitive detector. Berkeley Lab will lead US participation in the international CUPID project.

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