Researchers accelerated protons to 132 MeV, nearly half the speed of light, using an ultrathin, large-area suspended graphene target in a laser-driven ion acceleration experiment. The team combined expertise across institutions in Japan, Taiwan, the UK, and France to achieve the high-energy particle movement.
Osaka scientists use long-pulse lasers to accelerate protons
Scientists at the University of Osaka utilized a relatively long-pulse, moderate-intensity laser at the Institute of Laser Engineering for the breakthrough. Instead of deploying the ultra-short, ultra-intense pulses commonly favored in similar physics experiments, the setup relied on a 1.5-picosecond pulse duration. This sustained laser output allowed protons to accelerate for several picoseconds, which outlasts the acceleration windows typical in short-pulse configurations.
Surfing Acceleration Through Propagating Electrostatic Waves
Computer simulations mapped the underlying physics as a process resembling “surfing acceleration.” Rather than absorbing energy from a single short kick, protons continuously gained momentum as they rode a propagating electrostatic wave moving directly through the laser-generated plasma. This sustained interaction accounts for the particles reaching nearly half the speed of light.
Neural Network Detection of Faint Ion Impacts
Because high-energy protons remain exceptionally rare and produce very faint detector signals, identifying them demanded extensive data processing. Researchers scanned millions of microscope images of the detector surface to detect individual ion impacts. To automate and refine this search, the team trained a convolutional neural network that reached 99.2% precision in separating genuine high-energy proton signals from background noise.
What laser pulse duration and proton speeds were used?
What laser pulse duration was used in the Osaka experiment?
The experiment utilized a relatively long pulse lasting 1.5 picoseconds.
What top speed did the accelerated protons reach?
The protons were accelerated to 132 MeV, which is nearly half the speed of light.
How accurate was the neural network at spotting proton signals?
The convolutional neural network achieved 99.2% precision in distinguishing genuine high-energy proton impacts from background detector noise.
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