This initial demonstration achieved an acceleration gradient, or amount of energy gained per length, of 300 million electronvolts
So-called killer electrons, which are charged particles revved up to energies greater than 1 million electronvolts
, punch through the skin of spacecraft.
The ions--a searing beam of 30 trillion protons, with energies up to 50 million electronvolts
(MeV)--burst from the far side of the target.
The High-Energy Transient Experiment (HETE), an international project involving the United States, France, Italy, and Japan, carries a spectrometer to measure gamma-ray bursts ranging in energy from 6,000 to 1 million electronvolts