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We present an automated method for tracking 3D motion in pla-nar tagged MRI. First, displacement between successive 2D image frames is estimated from their local phase, also known as HARP. The displacement estimates then drive a 3D finite element model which tracks systolic motion. The 3D model allows for 1) estimating 3D motion from niultiple 2D tagged(More)
Initial experimental results are presented for measurements of the emittance of an electron beam in the University of Maryland Electron Ring (UMER). Two independent sets of slit-collector systems are used to measure the emittance in the vertical and horizontal directions respectively. Results are then compared to the time integrated emittance measurements(More)
For space-charge-dominated beams, details of the beam distribution as it emerges from the source region can strongly influence beam evolution well downstream. This occurs because collective space-charge modes, excited as the beam is born, can remain undamped for many focusing periods. Nevertheless, traditional studies of the source region in particle beam(More)
Experimental and theoretical work has been carried out to study the longitudinal space-charge effects in a retarding field energy analyzer. A one-dimensional model for both a mono-energetic beam and a thermal beam has been developed for this purpose. The study shows that, if the current density inside the device were higher than a critical value, the(More)
The University of Maryland Electron Ring (UMER) is a small-scale experiment on space-charge dominated beams. The 100 ns, 10 keV electron beam fills up nearly one-half of the ring circumference. Here we review two models for the evolution of such beams, and present some initial results of measurements of longitudinal beam expansion for two initial line(More)
Alignment of experimental components is critical to operation of The University of Maryland Electron Ring (UMER). Procedures and equipment used to align components of the electron ring are presented. The compact nature of UMER (ring diameter ≈ 4 m) presents unique challenges and advantages associated with the placement of vacuum components, confinement and(More)
The University of Maryland Electron Ring (UMER) is a unique beam physics research facility located at the Institute for Research in Electronics and Applied Physics (IREAP), on the University of Maryland, College Park campus. By using a scaled, low-energy 10 keV electron beam, UMER accesses the intense, high-brightness, regime of beam operation in(More)
The University of Maryland electron ring (UMER) is a novel experimental storage ring designed to investigate the dynamics of large systems of collisionless particles that nevertheless interact via collective mechanisms. Heavily diagnosed and designed to circulate a 100 mA electron beam at 10 keV for several turns, UMER allows us to follow the evolution of(More)
Keywords: Particle-In-Cell Spectral Electromagnetic Fast fourier transform FFT Domain decomposition Parallel a b s t r a c t Pseudo-spectral electromagnetic solvers (i.e. representing the fields in Fourier space) have extraordinary precision. In particular, Haber et al. presented in 1973 a pseudo-spectral sol-ver that integrates analytically the solution(More)