Performance improvement of an extraction Lambertson septum magnet in the Spallation Neutron Source accumulator ring

• Main Author: J. G. Wang
• Format: Article
• Language: English
• Published: American Physical Society 2009-04-01
• Series: Physical Review Special Topics. Accelerators and Beams
• Online Access: http://doi.org/10.1103/PhysRevSTAB.12.042402

The Spallation Neutron Source ring extraction Lambertson septum magnet contains a strong skew quadrupole term, which has been identified as the source of causing a beam profile distortion on the target. We have performed 3D computer simulations to study the magnetic field quality in the magnet. The skew quad term is computed with different methods in simulations and is compared to measurement data. The origin of the large skew quad term is thoroughly investigated. The remedy for minimizing the skew quad term by modifying the magnet is proposed. Particle tracking is performed to verify the beam profile evolution through the existing and modified septum. The magnetic interference to the septum performance from an adjacent quadrupole is also assessed.