High-Field Magnetic Insertion for IOTA Electron Lenses

Most present cyclic accelerators of charged particles such as storage rings and cyclotrons traditionally rely on linearity of the particle optics, except where required to correct for effects such as chromaticity. In these machines, the focusing depends linearly on the offset of the particles from the axis and all particles oscillate at approximately the same frequency, the tune. One limit on the intensity of the beam in these machines is the maximum allowable spread of tunes, which is typically limited by the presence of various resonances. Higher intensity can be potentially achieved in an accelerator employing optics with so-called non-linear lattice having motion invariants enabling stable nonlinear motion. One of the ideas for ring is to produce a large tune spread using short nonlinear insertions – so-called “electron lens” – without reducing the region where the beam can be transported stably. In this project, it is proposed to develop a non-linear electromagnetic insertion for IOTA enabling full performance of the electron lens. That will be accomplished by development and comparative study of both normal and superconducting conducting magnetic systems consisting of main solenoid and set of bending and transfer solenoids. In Phase I of this project we will perform 2D and 3D magnetic simulations to optimize the poles geometry in the proposed non-linear magnetic insert; create a conceptual engineering design of the magnetic assembly, and develop manufacturing and acceptance plans, including vacuum chamber integration, and magnetic metrology instrumentation requirements. The layouts based on superconducting (SC) versions will also be examined for their size, performance and cost benefits. The so-called electron lens technique, for which this project will develop enabling components and instrumentation, is a promising novel technique to improve the performance of the storage rings and other circular accelerators, enabling to store and accelerate higher intensity beams in a stable and reliable way. This will be useful to multiple discovery science and industrial accelerator facilities.