Scientists Are Building Detectors to Reveal the Invisible Universe

Dr. Rupak Mahapatra, an experimental particle physicist, holds a SuperCDMS detector. The highly sensitive devices, which are fabricated at Texas A&M University, are deepening the search for dark matter and have potential applications in quantum computing. Credit: Texas A&M University Division of Marketing and Communications Most of the universe is made of dark matter and dark energy, yet scientists still don’t know what either one is. New ultra-sensitive detectors are being built to spot incredibly rare particle interactions that could finally reveal their nature.

Scientists have made remarkable progress in understanding the universe, yet most of it remains unexplained. About 95% of everything that exists is made up of dark matter and dark energy, leaving just 5% as the familiar matter we can see and touch. Dr. Rupak Mahapatra, an experimental particle physicist at Texas A&M University, is working to explore this unseen majority by creating highly sophisticated semiconductor detectors that rely on cryogenic quantum sensors. These instruments are used in experiments around the world and are designed to probe one of the deepest questions in modern physics. Mahapatra often describes the challenge using a familiar metaphor. He compares humanity’s limited grasp of the universe — or lack thereof — to a parable. “It’s like trying to describe an elephant by only touching its tail. We sense something massive and complex, but we’re only grasping a tiny part of it.” Mahapatra and his collaborators recently published their work in the respected journal Applied Physics Letters. A MINER detector that is used to search for low-energy neutrinos at the Texas A&M TRIGA reactor. This sapphire detector can be used for both dark matter searches and for detection of reactor neutrinos that can not only provide evidence of new physics but also enable nuclear non-proliferation. Credit: Texas A&M University Understanding Dark Matter and Dark Energy Dark matter and dark energy get their names from the fact that scientists still do not know what they are made of. Dark matter accounts for most of the mass in galaxies and galaxy clusters, playing a central role in shaping their structure across enormous distances. Dark energy refers to the phenomenon responsible for the universe’s accelerating expansion. In simple terms, dark matter acts to hold cosmic structures together, while dark energy drives them apart. Even though they dominate the universe, neither dark matter nor dark energy gives off, absorbs, or reflects light. This makes them extremely difficult to observe directly. Researchers instead study their influence through gravity, which affects how galaxies form and move. Dark energy is the largest component, representing about 68% of the universe’s total energy, while dark matter makes up roughly 27%. Texas A&M University graduate students, from left, Keith Hunter, Bailey Pickard and Mahdi Mirzakhani mounting detectors. Credit: Texas A&M University Detecting Whispers in a Hurricane At Texas A&M, Mahapatra’s team is developing detectors with extraordinary sensitivity. These devices are designed to register interactions from particles that rarely interact with ordinary matter, interactions that could provide vital clues about the nature of dark matter. “The challenge is that dark matter interacts so weakly that we need detectors capable of seeing events that might happen once in a year, or even once in a decade,” Mahapatra said. His group has contributed to a leading global search for dark matter using a detector known as TESSERACT. “It’s about innovation,” he said. “We’re finding ways to amplify signals that were previously buried in noise.” Texas A&M is one of only a small number of institutions participating in the TESSERACT experiments. Texas A&M University engineer Mark Platt (left) and experimental physicist Dr. Rupak Mahapatra in the fabrication facility, where the critical first step occurs: polishing a semiconductor crystal to a flatness 1/100th the thickness of a human hair. Credit: Texas A&M University Pushing the Limits of Detection Technology Mahapatra’s current work builds on decades of experience advancing particle detection methods. For the past 25 years, he has been involved with the SuperCDMS experiment, which has carried out some of the most sensitive dark matter searches to date. In a landmark 2014 paper published in Physical Review Letters, Mahapatra and his colleagues introduced voltage-assisted calorimetric ionization detection in the SuperCDMS experiment — a breakthrough that allowed scientists to investigate low-mass WIMPs, a leading dark matter candidate. This innovation greatly expanded the range of particles that experiments could detect. A wafer with many different designs of chips for the TESSERACT project. Credit: Texas A&M University In 2022, Mahapatra co-authored another study that examined multiple approaches to finding a WIMP, including direct detection, indirect detection, and collider searches. The research highlights the importance of combining different methods to address the dark matter problem. “No single experiment will give us all the answers,” Mahapatra notes. “We need synergy between different methods to piece together the full picture.” Understanding dark matter goes beyond academic curiosity. It may be essential to uncovering the fundamental laws that govern the universe. “If we can detect dark matter, we’ll open a new chapter in physics,” Mahapatra said. “The search needs extremely sensitive sensing technologies and it could lead to technologies we can’t even imagine today.” Texas A&M University experimental particle physicist Dr. Rupak Mahapatra with a R&D detector mounted in a dilution fridge that cools it to 100,000 times cooler than room temperature. Credit: Texas A&M University What Are WIMPs? WIMPs (Weakly Interacting Massive Particles) are among the most promising theoretical candidates for dark matter. These hypothetical particles would interact through gravity and the weak nuclear force, which explains why detecting them is so difficult. Why they matter: If WIMPs exist, they could account for the missing mass in the universe. How we search: Experiments such as SuperCDMS and TESSERACT use ultra-sensitive detectors cooled to near absolute zero to capture rare interactions between WIMPs and ordinary matter. The challenge: A WIMP could pass through Earth without leaving any detectable signal, meaning scientists may need years of observations to identify even a single event. Reference: “Spontaneous generation of athermal phonon bursts within bulk silicon causing excess noise, low energy background events, and quasiparticle poisoning in superconducting sensors” by C. L. Chang, Y.-Y. Chang, M. Garcia-Sciveres, W. Guo, S. A. Hertel, X. Li, J. Lin, M. Lisovenko, R. Mahapatra, W. Matava, D. N. McKinsey, P. K. Patel, B. Penning, H. D. Pinckney, M. Platt, M. Pyle, Y. Qi, M. Reed, I. Rydstrom, R. K. Romani, B. Sadoulet, B. Serfass, P. Sorensen, B. Suerfu, V. Velan, G. Wang, Y. Wang, M. R. Williams, V. G. Yefremenko and TESSERACT Collaboration, 30 December 2025, Applied Physics Letters. DOI: 10.1063/5.