The Tibet ASgamma experiment, a China-Japan joint research project, has discovered the highest energy cosmic gamma rays ever observed from an astrophysical source—in this case, the Crab Nebula. The experiment detected gamma rays ranging from > 100 Teraelectron volts (TeV) (Fig.1) to an estimated 450 TeV. Previously, the highest gamma-ray energy ever observed was 75 TeV by the HEGRA Cherenkov telescope.
Source:
https://phys.org/news/2019-07-highest-energy-gamma-rays-tibet-asgamma.html