The synchrotron evolved from the cyclotron, the first cyclic particle accelerator. The ions are first accelerated by means of a cyclotron or synchrotron. Lawrence began converting his old 37-inch cyclotron into a giant mass spectrometer. Orbitrap instruments are similar to Fourier transform ion cyclotron resonance mass spectrometers (see text below). It is made by proton bombardment of O in a cyclotron or linear particle accelerator. The recoil experienced by a particle emitting cyclotron radiation is called radiation reaction. Due to an effect now known as cyclotron radiation, these electrons radiate radio frequency energy. In a particle accelerator, such as a cyclotron, alpha particles are collided with the bismuth. He produced tritium using the cyclotron and measured its lifetime. Technetium-99m was discovered as a product of cyclotron bombardment of molybdenum. Synchrocyclotrons have not been built since the isochronous cyclotron was developed. IU also features a world-class cyclotron operated by the Department of Physics. This is in contrast to the classical cyclotron, where this frequency is constant. Oliphant also travelled to Berkeley to meet with Ernest Lawrence, inventor of the cyclotron. Chadwick set about acquiring a cyclotron for Liverpool.