Adjustment and Test of the 300 MeV Extraction System for the NASA 600 MeV Synchrocyclotron

A regenerative system for extracting 300 MeV protons from the NASA 600 MeV synchrocyclotron at Langley Research Center was installed and tested. This system,1 which brings the protons out of the accelerator through a 20-foot long channel from a point almost half of the normal exit radius, was designed to have some manual adjustments of the iron components to produce the magnetic field shape necessary for successful extraction. This paper describes the magnetic measurements, orbit calculations and magnetic calculations that were used for adjusting this extraction system, which successfully extracted reduced energy protons with about 20% of the full energy current. Initial adjustments in the location and quantity of iron were made when magnetic measurements were performed using orbit calculations and phase-space plots based on the measured magnetic fields which were systematically altered until the phase-space plots indicated that the peeler-regenerator sections would produce extraction of protons with acceptable energy. During the final adjustments, using radiographic techniques to locate the proton beam in the extraction channel, alterations were made to various sections of the channel permitting it to accept the proton energy and entrance angle produced by the peeler-regenerator sections.