Camera sensors repurposed for antimatter research

The new device can pinpoint antiproton annihilations with a resolution of about 0.6 micrometres, making a 35-fold improvement over previous real-time methods.

This is part of an ongoing mission to measure the free-fall of antihydrogen under Earth’s gravity with high precision. AEgIS’ approach involves producing a horizontal beam of antihydrogen and measuring its vertical displacement using a device, a moiré deflectometer, that reveals tiny deviations in motion and a detector that records the antihydrogen annihilation points.

“For AEgIS to work, we need a detector with incredibly high spatial resolution, and mobile camera sensors have pixels smaller than 1 micrometer,” explained Francesco Guatieri from the research neutron source FRM II at TUM and Principal Investigator of the research. “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. 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.”

The researchers used optical image sensors that had demonstrated their capability of imaging low-energy positrons in real time.

“We had to strip away the first layers of the sensors, which are made to deal with the advanced integrated electronics of mobile phones,” added Guatieri. “This required high-level electronic design and micro-engineering.”

“This is a game-changing technology for the observation of the tiny shifts due to gravity in an antihydrogen beam travelling horizontally, and it can also find broader applications in experiments where high position resolution is crucial, or to develop high-resolution trackers,” said Dr. Ruggero Caravita, AEgIS Spokesperson. “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.”