A new high-resolution separator for high-intensity secondary beams

Abstract

The NSCL has proposed an upgrade to its facility to provide primary beams of significantly higher intensity and higher energy for studies of nuclear reactions and nuclear structure, particularly to provide those primary beams needed to produce intense secondary beams. The center piece of this project is the replacement of the A1200 fragment separator with a new high-acceptance device called the A1900. The new fragment separator will connect the upgraded cyclotrons with the existing beamlines and provide the higher-intensity beams to the experimental equipment. Large gains in primary beam intensity, typically two or three orders of magnitude, will result from accelerating low charge-state ions in the K500 accelerator followed by stripping and further acceleration in the K1200 machine. Additional large gains in the intensity of the secondary beams will come from the very high acceptance of the A1900 fragment separator. The new separator, relying on large superconducting magnets, will accept over 90% of a variety of projectile fragmentation products. The ready availability of intense beams over the entire range of atomic number and masses will open new vistas in nuclear structure through the production and study of many new and previously inaccessible nuclei. The design of the A1900 superconducting quadrupoles and dipoles based on extensive experience with similar magnets is well underway.