Feasibility studies of the H~- acceleration in the K130 cyclotron in jyvaskyla

摘要

High intensities of proton beams are needed in the Jyvaskyla cyclotron for radioisotope production and in some light ion induced fission experiments. At present the extraction efficiency of high-energy proton beams (1~(st) harmonic) is 60-70%. This limits the maximum extracted beam current to about 25 μA. In order to minimise activation of the cyclotron and and to allow for higher intensities we have studied the possibility of H~- acceleration with stripping extraction. It was found that beam losses due to residual gas at a normal pressure of p～10~(-7) mbar in the cyclotron do not exceed a few percent as well as the beam losses due to electromagnetic dissociation of H~- ions accelerated up to 75 MeV are lower than 2%. The beam optics calculations show that proton beam can be extracted with an efficiency of 100% directed into the given region and then matched with the existing beam line. Some additional focusing for example using a passive channel inside the vacuum chamber is needed.