ORNL, Oak Ridge, Tennessee, USA
The research program at the SNS Beam Test Facility is focused on resolving observed model/measurement discrepancies that preclude accurate loss prediction in high-power linacs. The current program of study is focused on deploying direct 6D measurements to reconstruct a realistic model of the initial beam distribution at the RFQ output. This detailed characterization also provides an opportunity for benchmark of RFQ simulations. Here we compare PARMTEQ predictions against 5D-resolved (x, x’, y, y’, dE) phase space measurements of the BTF H− bunch, focusing on the transverse distribution. This work is an extension of [1], which focused on the longitudinal phase space.
[1] K. Ruisard et al., doi: 10.1103/PhysRevAccelBeams.23.124201.
[2] A. Hoover et al., "Measurements of the Five-Dimensional Phase Space Distribution of a High-Intensity Ion Beam," these proceedings.
ORNL, Oak Ridge, Tennessee, USA
UTK, Knoxville, Tennessee, USA
JAEA/J-PARC, Tokai-mura, Japan
A realistic full duty factor laser stripping charge exchange injection scheme for future 1.3 GeV beam at the SNS is considered. Different schemes of laser stripping involving combinations of photoexcitation, photoionization and magnetic field stripping are calculated. The laser power and magnetic field strength needed for different approaches are estimated and compared. The most practical scheme of laser stripping is selected for development.
THXD3
RadiaBeam, Santa Monica, California, USA
ORNL, Oak Ridge, Tennessee, USA
RadiaBeam is developing the Bunch Shape Monitor (BSM) with improved performance that incorporates three major innovations. First, the collection efficiency is improved by adding a focusing field between the wire and the entrance slit. Second, an improvement of the measurement speed is achieved by sampling longitudinal profiles of multiple energy slices simultaneously. Finally, the design is augmented with both a movable wire and a microwave deflecting cavity to add functionality and enable measuring the transverse profile as a wire scanner. In this paper we present the design of the BSM and its sub-systems as well as the initial test results of the new focusing system at SNS beamline.
ORNL, Oak Ridge, Tennessee, USA
No simulation of intense beam transport has accurately reproduced measurements at the level of beam halo. One potential explanation of this discrepancy is a lack of knowledge of the initial distribution of particles in six-dimensional (6D) phase space. A direct 6D measurement of an ion beam was recently performed at the Spallation Neutron Source (SNS) Beam Test Facility (BTF), revealing nonlinear transverse-longitudinal correlations in the beam core that affect downstream evolution. Unfortunately, direct 6D measurements are limited in resolution and dynamic range; here, we discuss the use of three slits and one screen to measure a 5D projection of the 6D phase space distribution, overcoming these limitations at the cost of one dimension. We examine the measured 5D distribution before and after transport through the BTF and compare to particle-in-cell simulations. We also discuss the possibility of reconstructing the 6D distribution from 5D and 4D projections.