Reviewed by Lexie CornerApr 3 2025
Researchers from the Technical University of Munich, collaborating on the "Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy" (AEgIS) and other projects at CERN's Antimatter Factory, such as ALPHA and GBAR, aim to measure the free-fall of antihydrogen in Earth's gravitational field with high precision, utilizing various methodologies.
The optical anti-matter imager with the 60 photo sensors taken from mobile phones. Image Credit: Andreas Heddergott / TUM
AEgIS uses a technique that generates a horizontal beam of antihydrogen and measures its vertical movement with a moiré deflectometer, which detects small changes in motion, along with a detector that captures points of antihydrogen annihilation.
For AEgIS to work, we need a detector with incredibly high spatial resolution, and mobile camera sensors have pixels smaller than 1 micrometer. We have integrated 60 of them in the single photographic detector, the Optical Photon and Antimatter Imager (OPHANIM), with the highest number of pixels currently operational: 3840 MPixels.
Francesco Guatieri, Principal Investigator, Research Neutron Source FRM II, Technical University of Munich
Guatieri said, “Previously, photographic plates were the only option, but they lacked real-time capabilities. Our solution, demonstrated for antiprotons and directly applicable to antihydrogen, combines photographic-plate-level resolution, real-time diagnostics, self-calibration, and a good particle collection surface, all in one device.”
Converted Image Sensors
The scientists used optical image sensors, which have been shown to image low-energy positrons in real-time with exceptional resolution.
We had to strip away the first layers of the sensors, which are made to deal with the advanced integrated electronics of mobile phones. This required high-level electronic design and micro-engineering.
Francesco Guatieri, Principal Investigator, Research Neutron Source FRM II, Technical University of Munich
Michael Berghold and Markus Münster, both master's students at the TUM School of Engineering and Design, were instrumental in the project.
Extraordinary Resolution
This is a game-changing technology for the observation of the tiny shifts due to gravity in an antihydrogen beam traveling horizontally, and it can also find broader applications in experiments where high position resolution is crucial, or to develop high-resolution trackers. This extraordinary resolution enables us also to distinguish between different annihilation fragments, paving the way for new research on low-energy antiparticle annihilation in materials.
Dr. Ruggero Caravita, Department of Physics, University of Trento
Dr. Ruggero Caravita is a spokesperson for AEgIS.
Journal Reference:
Berghold, M., et al. (2025) Real-time antiproton annihilation vertexing with submicrometer resolution. Science Advances. doi.org/10.1126/sciadv.ads1176.