Allison rebuilt his accelerator, which he called the "kevatron", because it could accelerate particles to energies of 400 KeV. The name was a reference to the massive bevatron being built at the Lawrence Berkeley Laboratory, which was planned to accelerate particles to billions of electron volts. Allison still believed that there were useful results still to be found with low energies. He became a pioneer of what became known as "heavy ion physics", accelerating protons and deuterons, and using lithium and beryllium as targets. The data on these reactions of light elements would subsequently prove useful in the study of stellar nucleosynthesis.