Cooking Carbon Dots -- Making an Instant Neutrino Detector in Your Kitchen

Liquid scintillators underpin a wide range of radiation detectors, including those used in neutrino physics, but typically rely on organic fluors dissolved in hazardous and costly solvents. Here, we show that carbon dots - nanoscale fluorescent carbon materials - synthesised from simple household ingredients using a microwave can function as water-based liquid scintillators. These carbon dots dispersed in water produce light yields up to 70 +/- 20 photons per MeV and enable the detection of atmospheric muons. This yield is sufficient to detect low-energy protons in water Cherenkov neutrino detectors, expanding their programs in both particle physics and astrophysics. These results establish an accessible, low-cost and environmentally benign route to scintillator development, opening new opportunities for large-scale radiation detection.