Generalized phase-space tomography for intense beams

Abstract

Tomographic phase-space mapping in an intense particle beam is reviewed. The diagnostic is extended to beams with space-charge by assuming linear forces and is implemented using either solenoidal or quadrupole focusing lattices. The technique is benchmarked against self-consistent simulation and against a direct experimental sampling of phase-space using a pinhole scan. It is demonstrated that tomography can work for time-resolved phase-space mapping and slice emittance measurement. The technique is applied to a series of proof-of-principle tests conducted at the University of Maryland.

Phase space reconstruction technique for beam optimization in the Low Energy High Intensity Proton Accelerator (LEHIPA)

“…In tomography, different 'orientations' within the phase space are accomplished by changing the transverse phase advances between the observation point and the reconstruction point, essentially by changing the magnet strength. Various algorithms, such as the back projection, Filtered Back-Projection (FBP) algorithm [29][30][31][32] and iterative algorithms like Algebraic Reconstruction Technique (ART) [28,34,41], Simultaneous Iterative Reconstruction Technique (SIRT) [42,43] & Iterative Least Square Technique (ILST) [43], are employed to generate higher-dimensional images from a series of projections taken at different orientations ranging from 0 to π. The respective difference between these iterative algorithms lies in their approach to making successive corrections: whether they correct ray by ray, pixel by pixel, or simultaneously correct the entire dataset.…”

“…)can be the beam distribution in any two dimensions. Using the Fourier Slice Theorem, the original distribution is expressed in terms of the Fourier transform of the Radon transform [29][30][31][32],…”

“…Tomographic reconstruction is a powerful technique used to reconstruct a higher n-dimensional space from projections at a lower (n-1) dimension using the Radon transform. The (n-1) dimensional projection of an n-dimensional image as a function of viewing angle, θ, is described by the Radon transformation [25][26][27][28][29][30][31][32]. The computed tomography is an attempt to achieve an inverse Radon transformation.…”

“…The computed tomography is an attempt to achieve an inverse Radon transformation. The technique is modified for beam physics using the Fourier slice theorem [29][30][31][32] and by scaling the spatial profile to make it comparable to the Radon transform. McKee et al and others [20,32,33] had used this technique to reconstruct phase-space with greater accuracy by combining CT with quadrupole scanning.…”

Core-halo boundary in a sheet beam model

“…This is particularly relevant if one takes into account that present experimental methods allow for a full multi-dimensional beam phase-space measurement. [34][35][36][37][38][39] The paper is organized as follows. In Sec.…”