Status of Musl-2, the Second Microtron Using a Superconducting Linac

A second racetrack microtron, MUSL-2, is being assembled in the area previously occupied by the 300 MeV betatron. It uses a Van de Graaff to inject electrons at about 2 MeV, a 6 meter, 1.3 GHz superconducting linac made for us at the Stanford High Energy Physics Laboratory as the accelerating section and the magnets from MUSL-1 for recirculation
¹
. A digital control console has been installed to operate the linac and the injection and recirculation systems. The CTI 1400 helium liquefier together with the low pressure heat exchanger from MUSL-1 maintains the linac at about 2 K. Beams of 10 microamperes with energies up to 14 MeV with a resolution of 0.2% are being used for nuclear experiments. Continuous beams up to 72 MeV will be available after the installation of the 6 pass system is completed. Present plans for moving toward higher energies involve the use of MUSL-2 to inject electrons with energies up to 72 MeV into a second superconducting linac in a microtron operating at v=1. With return orbits separated by 7.35 cm relatively small magnets in the second system can accommodate 18 additional passes. At 12 MeV per pass electrons would reach a final energy of 288 MeV.