The 200 nA Variable energy polarized proton beam at triumf

A Lamb‐shift type polarized H− source has been recently upgraded to produce a 1 μA beam current within a normal lized emittance of about 0.3π mm‐mrad. The polarization, enhanced through a diabatic field reversal, is approximately 80%. The 500 eV ions are accelerated and focused via a 5 kV gap lens to match the acceptance of a 300 kV acceleration bute. At 300 keV, at the entrance of a 45 m long electrostatic transport line, the spin is rotated via a Wien filter to compensate for the pression caused by the cyclotron’s stray magnetic field along the line. Spin aberrations along the injection path, including the electrostatic spiral inflector, have been calculated to be less than a few degrees. A slight loss in polarization has been measured in the cyclotron between 200 MeV and 520 Mev; however, the polarization of the 200 nA extracted beam is greater than 70% at all energies. The extrated beam is delivered primarily to two beam lines in one experimental area. One is equipped with a ∠500 keV magnetic spectrom...