Particle acceleratorSee 'accelerator'. where charged particles repeatedly pass an electrical acceleration field while they move helically from their source in the centre of the machine to the outside. The particles are held in the helical level by a strong magnet. A cyclotron is not suitable to accelerate electrons. Due to the relativistic mass increase with growing speed the maximum energyAbility to do work or diffuse heat. The unit of energy is th... achievable with a cyclotron is limited to about 400 MeVMegaelectron volt, 1,000,000 eV. for protons.