Junior Peña, neutrino hunter

Growing up in South Central Los Angeles, Junior Peña learned to keep his eyes down and his schedule full. In his neighborhood, a glance could invite trouble, and many kids—including his older brother—were pulled into gang culture. He knew early on that he wanted something else. With his parents working long hours, he went to after-school programs, played video games, and practiced martial arts. But his friends had no idea that he also spent hours online poring over textbooks and watching lectures, teaching himself advanced mathematics and philosophy. “Being good at school wasn’t how people saw me,” he says. 

One night in high school, he came across a YouTube video about the Higgs boson—the so-called “God particle,” thought to give mass to nearly everything in the universe. “I remember my mind being flooded with questions about life, the universe, and our existence,” he recalls. He’d already looked into philosophers’ answers to those questions but was drawn to the more concrete explanations of physics.

After his independent study helped Peña pass AP calculus as a junior, his fascination with physics led him to the University of Southern California, the 2019 session of MIT’s Summer Research Program, and then MIT for grad school. Today, he’s working to shed light on neutrinos, the ghostly uncharged particles that slip effortlessly through matter. Particles that would require a wall of lead five light-years thick to stop.

As a grad student in the lab of Joseph Formaggio, an experimental physicist known for pioneering new techniques in neutrino detection, Peña works alongside leading physicists designing technology to precisely measure what are arguably the universe’s most elusive particles. Emanating from such sources as the sun and supernovas (and generated artificially by particle accelerators and nuclear reactors), neutrinos reveal their presence through an absence. Their existence was initially posited in the 1930s by the physicist Wolfgang Pauli, who noticed that energy seemed to go missing when atoms underwent a process known as radioactive beta decay. According to the law of conservation of energy, the total energy of the particles emitted during radioactive decay must equal the energy of the decaying atom. To account for the missing energy, Pauli proposed the existence of an undetectable particle that was carrying it away. 

Einstein’s E = mc² tells us that if energy is missing, then mass must be too. Yet according to the standard model of physics—which offers our most trusted theory for how particles behave—neutrinos should have no mass at all. Unlike other particles, they don’t interact with the Higgs field, a kind of cosmic molasses that slows particles down and gives them mass. Because they pass through it untouched, they should remain massless. 

But by the early 2000s, researchers had discovered that neutrinos, which had first been detected in the 1950s, can shift between three types, a feat possible only if they have mass. So now the tantalizing question is: What is their mass? 

Determining neutrinos’ exact mass could explain why matter triumphed over antimatter, refine models of cosmic evolution, and clarify the particles’ role in dark matter and dark energy. And the Formaggio Lab is part of Project 8, an international collaboration of 71 scientists in 17 institutions working to make that measurement. To do this, the lab uses tritium, an unstable isotope of hydrogen that decays into helium, releasing both an electron and a particle called an antineutrino (“every particle has an antiparticle counterpart,” Formaggio explains). By precisely measuring the energy spectrum of those electrons, scientists can determine how much energy is missing, allowing them to infer the neutrinos’ mass.

At the heart of this experiment is a novel detection method called cyclotron radiation emission spectroscopy (CRES), first proposed in 2008 by Formaggio and his then postdoc Benjamin Monreal, which “listens” to the faint radio signals emitted as electrons spiral through a magnetic field. Peña was instrumental in designing a crucial part of the tool that will make this possible: a copper cavity that he likens to a guitar, with the electrons released during beta decay acting like plucked strings. The cavity will amplify their signals, helping researchers to measure them exactly. Peña spent more than a year developing and refining a flashlight-size prototype of the device in collaboration with machinists and fellow physicists.

JESSICA CHOMIK-MORALES, SM ’25

“He had to learn the [design and simulation] software, figure out how to interpret the signals, and test iteration after iteration,” says Formaggio, Peña’s advisor. “It’s been incredible watching him take this from a rough idea to a working design.”

The design of Peña’s cavity had to balance competing demands. It needed a way to extract the electrons’ signals that was compatible with the researchers’ methods for calibrating the system, one of which involves using an electron gun to inject electrons of a known, precise energy into the cavity. And it also needed to preserve the properties of the electromagnetic fields within the cavity. In May, Peña sent his final prototype to the University of Washington, where it was installed in July. Researchers hope to begin calibration this fall. Then Peña’s cavity and the full experimental setup will be scaled up so in a few years they can begin collecting CRES data using tritium.

“We’ve been working toward this for at least three years,” says Jeremy Gaison, a Project 8 physicist at the Pacific Northwest National Lab. “When we finally turn on the experiment, it’s going to be incredible to see if all of our simulations and studies actually hold up in real data.”

Peña’s contribution to the effort “is the core of this experiment,” says Wouter Van De Pontseele, another Project 8 collaborator and former Formaggio Lab postdoc. “Junior took an idea and turned it into reality.” 

Project 8 is still in its early stages. The next phase will scale up with larger, more complex versions of the technology Peña played a key role in developing, culminating in a vast facility designed to hunt for the neutrino’s mass. If that is successful, the findings could have profound implications for our understanding of the universe’s structure, the evolution of galaxies, and even the fundamental nature of matter itself.

Eager to keep probing such open questions in fundamental physics, Peña is still exploring options for his postdoc work. One possibility is focusing on the emerging field of levitated nanosensors, which could advance gravitation experiments, efforts to detect dark matter, and searches for the sterile neutrino, a posited fourth variety that interacts even more rarely than the others.

“Experimental particle physics is long-term work,” says Van De Pontseele. “Some of us will stay on this project for decades, but Junior can walk away knowing he made a lasting impact.”

Peña also hopes to have a lasting impact as a professor, opening doors for students who, like him, never saw themselves reflected in the halls of academia. “A summer program brought me here,” he says. “I owe it to the next kid to show they belong.”

MIT is worth fighting for

As I write in late July, we’re contending with a major tax increase on the annual returns from MIT’s endowment as well as other investments and assets. This new tax burden will strain the resources we use to support research, innovation, and student scholarships and financial aid—the heart and soul of the Institute. 

Infinite Threads

Textiles account for 5% of landfill space—and clothing made with polyester can take up to 200 years to decompose. Massachusetts tackled the problem by banning disposal of clothing and fabrics in 2022. And Infinite Threads, a spinoff of the Undergraduate Association Sustainability Committee, is addressing it by collecting lightly used clothing from the MIT community and selling it for $2 to $6 per item at popup sales held several times each semester. 

“Our goal is simple: We want to keep clothing out of landfills,” says Cameron Dougal ’25, who led the effort with Erin Hovendon ’26 in 2024–’25. That year, the group sold over 1,000 items and gave about 750 pounds of unsold goods to Helpsy, an organization that collects used clothing for resale and recycling. Infinite Threads uses proceeds from its sales to pay student workers and to rent a U-Haul to bring clothing to the popups. 

SARAH FOOTE

In addition to helping the planet, offering affordable clothing options generates a lot of positive feedback on campus. “I love hearing from students that they got clothing items they now wear frequently from one of our sales,” says Hovendon. 

Infinite Threads also gives away leftover T-shirts from residence hall events and career fairs, which Dougal says demonstrates the importance of a hyperlocal reuse ecosystem. “As soon as these types of items leave campus,” he says, “there is a much lower chance that they will find a new home.”

Fix damaged art in hours with AI

Art restoration takes steady hands and a discerning eye. For centuries, conservators have identified areas needing repair and then mixed the exact shades needed to fill in one area at a time. Restoring a single painting can take anywhere from a few weeks to over a decade. Now an MIT graduate student in mechanical engineering has used artificial intelligence to speed up the process by orders of magnitude.

Digital restoration tools are not new; computer vision, image recognition, and color matching have all helped generate repaired versions of damaged paintings in recent years. But until now, there has been no way to apply the results directly onto an original canvas. Instead, they are usually displayed virtually or printed as stand-alone works.

In his study, Alex Kachkine, SM ’23, presents a new method he’s developed that involves printing the restoration on a very thin polymer film that can be carefully aligned with a painting and adhered to it or easily removed. As a demonstration, he used the method to repair a highly damaged 15th-century oil painting he owned. First he used traditional techniques to clean the painting and remove any past restoration efforts. Then he scanned the painting, including the many regions where paint had faded or cracked, and used existing algorithms to create a virtual version of what it may have looked like originally.

Next, Kachkine used software he developed to create a map of regions on the original painting that require infilling, along with the exact colors needed. The method automatically identified 5,612 regions in need of repair and filled them in using 57,314 different shades. This map was then translated into a physical, two-layer mask printed onto polymer-based films. The first layer was printed in color, while the second layer was printed in the exact same pattern but in white.

“In order to fully reproduce color, you need both white and color ink to get the full spectrum,” Kachkine explains. He used high-fidelity commercial inkjets to print the mask’s two layers, which he carefully aligned with the help of computational tools he developed. Then he overlaid them by hand onto the original painting and adhered them with a thin spray of conventional varnish. The films are made from materials that can be easily dissolved in case conservators need to reveal the original, damaged work. The entire process took 3.5 hours, which he estimates is about 66 times faster than traditional restoration methods.

If this method is adopted widely, Kachkine emphasizes, conservators should be involved at every step, to ensure that the final work is in keeping with an artist’s style and intent. The digital file of the mask can also be saved to document exactly what was restored. “Because there’s a digital record of what mask was used, in 100 years, the next time someone is working with this, they’ll have an extremely clear understanding of what was done to the painting,” Kachkine says. “And that’s never really been possible in conservation before.”

The result, he hopes, will be a new lease on life for many works that have not had a chance to be repaired by hand. “There is a lot of damaged art in storage that might never be seen,” he says. “Hopefully with this new method, there’s a chance we’ll see more art.” 

Emergency help for low blood sugar

Most people with type 1 diabetes inject insulin to prevent their blood sugar levels from getting too high. However, if their blood sugar gets too low, it can lead to confusion, seizures, and even death.

To combat this hypoglycemia, some patients carry syringes of glucagon, a hormone that stimulates release of glucose. Now MIT engineers have developed an alternative that could work even when people don’t realize they are becoming hypoglycemic. It could also help during sleep, or for children who are unable to inject themselves. “Our goal was to build a device that is always ready to protect patients,” says Daniel Anderson, a professor in MIT’s Department of Chemical Engineering and the senior author of a study on the work.

The implantable device, about the size of a quarter, contains a polymer reservoir holding powdered glucagon and sealed with a material that can be programmed to change shape when heated. It also includes an antenna that allows the user to remotely turn on a small electrical current, which heats that material until it bends and releases the drug. Because the device can receive wireless signals, it could also be triggered automatically by a glucose monitor.

The researchers have successfully tested the implant in mice and say it could also be used to deliver epinephrine to treat heart attacks or prevent anaphylactic shock. 

‘Bubbles’ turn air into drinkable water

Today, 2.2 billion people in the world lack access to safe drinking water. But the atmosphere contains millions of billions of gallons of water in the form of vapor, and researchers have tried various strategies to capture and condense it in places where traditional sources are inaccessible. Now MIT engineers have improved on that approach with an atmospheric water harvester based on an absorbent hydrogel.

The gel they developed has more vapor-carrying capacity than some materials others have used to trap water from the air, and it is less likely to leak the salts that are often embedded in hydrogels to increase absorption. They also increased its surface area, and thus the amount of vapor it can hold, by molding it into a pattern of small domes resembling bubble wrap. 

COURTESY OF THE RESEARCHERS

In the researchers’ prototype device, a half-square-meter panel of the hydrogel is enclosed in a glass chamber coated with a cooling polymer film. When the vapor captured by the textured material evaporates, the bubbles shrink down in an origami-­like transformation. The vapor then condenses on the glass, where it can flow out through a tube.

The system runs entirely on its own, unlike other designs that require batteries, solar panels, or electricity from the grid. The team ran it for over a week in Death Valley, California—the driest place in North America. Even in those conditions, it squeezed clean water from the air at rates of up to 160 milliliters (about two-thirds of a cup) per day.

“We have built a meter-scale device that we hope to deploy in resource-limited regions, where even a solar cell is not very accessible,” says Professor Xuanhe Zhao, the senior author of a paper on the work. The team estimates that a small array of the panels could passively supply a household with drinking water even in a desert, with greater production in temperate and tropical climates.

Chandrakasan named provost

Anantha Chandrakasan became the Institute’s new provost on July 1, succeeding Cynthia Barnhart, SM ’86, PhD ’88, who announced her decision to step down in February.

Chandrakasan, who earned his BS, MS, and PhD in electrical engineering and computer science from the University of California, Berkeley, joined MIT in 1994. Head of the Energy-Efficient Circuits and Systems Group, he has been dean of the School of Engineering since 2017 and MIT’s inaugural chief innovation and strategy officer, playing a key role in launching multiple new initiatives, since 2024. He headed the Department of Electrical Engineering and Computer Science, MIT’s largest academic department, for six years.

As MIT’s senior academic and budget officer, Chandrakasan will focus on understanding institutional needs and strategic financial planning, attracting and retaining top talent, and supporting cross-cutting research, education, and entrepreneurship programming. On all these fronts, he plans to seek frequent input from across the Institute. He also plans to establish a provost faculty advisory group, as well as student/postdoc advisory groups and an external provost advisory council.

“There is a tremendous opportunity for MIT to be at the center of the innovations in areas where the United States wants to lead,” Chandrakasan says. “It’s about AI. It’s about semiconductors. It’s about quantum, the bio­security and biomanufacturing space—but not only that. We need students who can do more than just code or design or build. We really need students who understand the human perspective and human insights.” 

One-shot vaccines for HIV and covid

A team at MIT and the Scripps Research Institute has made important progress toward vaccines that can protect against HIV, and potentially other diseases, with a single dose.

The researchers treated mice with a vaccine that combines two different adjuvants, materials that help stimulate the immune system—one incorporating a compound previously developed by Scripps professor Darrell Irvine. 

Irvine and MIT professor J. Christopher Love, the senior authors of a paper on the work, had found that the combination helped generate more robust immune responses. In the new paper, they showed that the dual-adjuvant vaccine accumulated in the lymph nodes, where white blood cells known as B cells encounter antigens and undergo rapid mutations that generate new antibodies. The vaccine’s antigens remained there for up to a month, allowing the immune system to build up a much greater number and diversity of antibodies against the HIV protein than the vaccine given alone or with one adjuvant.

“When you think about the immune system sampling all of the possible solutions, the more chances we give it to identify an effective solution, the better,” Love says. 

This approach may mimic what occurs during a natural infection and could lead to an immune response so strong and broad that vaccines only need to be given once. Love says, “It offers the opportunity to engineer new formulations for these types of vaccines across a wide range of different diseases, such as influenza, SARS-CoV-2, or other pandemic outbreaks.”