Acceleration of alpha particles by the space radiation effects laboratory synchro-cyclotron

Abstract

A modification of the SREL synchro-cyclotron has been completed, allowing acceleration of alpha particles ( 2 4He ++) as well as protons. The main parts of the modification are in the rf system and the ion source. No changes in the main magnet, extraction channel or beam transport system have been required. The energy of extracted protons from the SREL synchrocyclotron is 588 MeV and the corresponding energy of alpha particles is 707 MeV. At the time of the initial testing, the beam intensity was found to be over 0.2 μA (6 × 10 11 alphas per second) near the extraction radius, and 0.3 μA at the radius of 28″ (86 MeV). The modified cyclotron operates reliably in both the proton and alpha-particle modes, with a period of about eight hours required for the changeover between modes.