UMAN, Manchester, United Kingdom
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
EMMA is the first non-scaling FFAG to be constructed, whose use of linear magnets means that the accelerating electron bunch rapidly crosses many resonances. We have modeled the capture and acceleration of bunches in the serpentine channel created by the radio-frequency cavities, and compare it to a proposed experiment in which induction cells allow slow acceleration. Two induction cores each providing ~20kV over 1.65 μs enable a number of resonance crossing experiments.
LBNL, Berkeley, California, USA
The Neutralized Drift Compression Experiment (NDCX-II) is an induction accelerator project currently in construction at Lawrence Berkeley National Laboratory for warm dense matter (WDM) experiments investigating the interaction of ion beams with matter at high temperature and pressure. The machine consists of a lithium injector, induction accelerator cells, diagnostic cells, a neutralized drift compression line, a final focus solenoid, and a target chamber. The machine relies on a sequence of acceleration waveforms to longitudinally compress the initial ion pulse from 600 ns to less than 1 ns in ~ 12 meters. Radial confinement of the beam is achieved with 2.5 T solenoids. In the initial hardware configuration, 30-50 nC of Li+ will be accelerated to 1.2 MeV and allowed to drift-compress to a peak current of ~ 20 A. Construction of the accelerator will be completed in the summer of 2011 and will provide a worldwide unique opportunity for ion-driven warm dense matter experiments as well as research related to novel beam manipulations for heavy ion fusion drivers. The basic design of the machine and the current status of the construction project will be presented.
PPPL, Princeton, New Jersey, USA
LLNL, Livermore, California, USA
Columbia University, New York, USA
Neutralized drift compression offers an effective means for particle beam focusing and current amplification. In neutralized drift compression, a linear longitudinal velocity tilt is applied to the beam pulse, so that the beam pulse compresses as it drifts in the focusing section. The beam intensity can increase more than a factor of 100 in the longitudinal direction. We have performed an analytical study of how errors in the velocity tilt acquired by the beam in the induction bunching module limits the maximum longitudinal compression. It is found in general that the compression ratio is determined by the relative errors in the velocity tilt. That is, one-percent errors may limit the compression to a factor of one hundred. However, part of pulse where the errors are small may compress to much higher values determined by the initial thermal spread of the beam pulse. Examples of slowly varying and rapidly varying errors compared to the beam pulse duration are studied.
BNL, Upton, Long Island, New York, USA
UCLA, Los Angeles, California, USA
LBNL, Berkeley, California, USA
A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 μm. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression eXperiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 μm of the induction cell axis has been demonstrated.