WEA4IO01
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, USA
Magnetized beams emerging from electron cyclotron resonance (ECR) ion sources have large statistical canonical angular momentum that substantially alters the beam dynamics. This paper examines the single-particle dynamics of such beams in non-axisymmetric lattice elements. The work supports commissioning activities at the FRIB Front End by illustrating how xy projections of the components of a multi-species beam become tilted due to dipoles and quadrupoles, which can complicate charge state selection with slits. The results help guide simulations performed using the PIC code WARP to achieve better optimization of the collimation in the charge selection system (CSS). Beam statistical angular momentum also evolves in the CSS which in turn changes the x- and y-plane emittances. Possible implications of this effect on the final thermalized beam emittances delivered by the Front End are discussed.
WEA4CO02
RadiaSoft LLC, Boulder, Colorado, USA
Fermilab, Batavia, Illinois, USA
Modern hadron accelerators such as spallation sources and neutrino factories must push the intensity limits to meet increasingly challenging goals. The Integrable Optics Test Accelerator (IOTA) is a small ring, currently under construction at Fermilab, which will explore advanced concepts in beam dynamics with low-energy proton beams with high space charge tune depression. Through use of a special nonlinear magnet insertion, large tune spread with amplitude can be achieved while preserving two integrals of motion for the single particle behavior. The tune shift and spread induced by space charge can disrupt the stability of these invariants. In this work we examine the behavior of these invariants in the presence of space charge. Simulations of a modified IOTA lattice that accounts for the space charge tune depression are shown, and the behavior of the invariants is examined.
Fermilab, Batavia, Illinois, USA
Using Synergia accelerator modeling package and Dynamic Mode Decomposition technique, the properties of the first transverse dipole mode in Gaussian bunches with space charge are compared at transverse coupling resonance and off-resonance. The Landau damping at coupling resonance and in the strong space charge regime is a factor of two larger, while the mode's tune and shape are nearly the same. While the damping mechanism in the off-resonance case fits well with the classical Landau damping paradigm, the enhancement at coupling resonance is due to a higher order mode-particle coupling term which is modulated by the amplitude oscillation of the resonance trapped particles.
WEA4CO04
Fermilab, Batavia, Illinois, USA
The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact on half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.
BNL, Upton, Long Island, New York, USA
A Low Energy RHIC electron Cooler (LEReC) is presently under construction at BNL to improve the luminosity of the Relativistic Heavy Ion Collider (RHIC). The required electron beam will be provided by a photoemission electron gun and accelerated by a RF linear accelerator. As a result, LEReC will be first bunched beam electron cooler. In addition, this will be the first electron cooler to cool beams under collisions. The achievement of very tight electron beam parameters required for cooling is very challenging and is being addressed by a proper beam transport and engineering design. In this paper, we describe accelerator physics requirements, design considerations and parameters, as well as associated challenges of such electron cooling approach.