Cockcroft Walton pre-injector
The Cockcroft-Walton accelerator (CW) is the first step in the proton accelerator facility at PSI. It generates protons and gives them a powerful energy boost before they are sped up further in the cyclotrons. The protons reach an energy of 870 keV: 60 keV come from the extraction voltage of the ion source, and another 810 keV are provided by the CW’s DC acceleration. For an air-insulated DC accelerator, that’s roughly the maximum energy achievable.
Injector-2 cyclotron for 72 MeV proton beams
The Injector‑2 is a ring cyclotron with 4 sector magnets that receives protons at a very low injection energy of 870 keV, provided by the Cockcroft‑Walton pre-injector. As the second stage of PSI’s three-stage proton accelerator facility, Injector‑2 further accelerates the protons to about 72 MeV. From there, the beam is fed into the large ring cyclotron, where the protons are finally brought to even higher energies.
Characteristics and values
• Injection ernergy: 870 keV (4.3% of light speed)
• Extraction energy: 72 MeV (37.1% of light dpeed)
• Beam current: 2.5 mA
