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arXiv · 1711.00539

Optimizing Beam Transport in Rapidly Compressing Beams on the Neutralized Drift Compression Experiment - II

Anton D. Stepanov·Erik P. Gilson·Igor D. Kaganovich·Peter A. Seidl·Arun Persaud·Qing Ji·Thomas Schenkel·Alex Friedman·John J. Barnard·David P. Grote
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Abstract

The Neutralized Drift Compression Experiment-II (NDCX-II) is an induction linac that generates intense pulses of 1.2 MeV helium ions for heating matter to extreme conditions. Here, we present recent results on optimizing beam transport. The NDCX-II beamline includes a 1-meter-long drift section downstream of the last transport solenoid, which is filled with charge-neutralizing plasma that enables rapid longitudinal compression of an intense ion beam against space-charge forces. The transport section on NDCX-II consists of 28 solenoids. Finding optimal field settings for a group of solenoids requires knowledge of the envelope parameters of the beam. Imaging the beam on scintillator gives the radius of the beam, but the envelope angle dr/dz is not measured directly. We demonstrate how the parameters of the beam envelope (r, dr/dz, and emittance) can be reconstructed from a series of images taken at varying B-field strengths of a solenoid upstream of the scintillator. We use this technique to evaluate emittance at several points in the NDCX-II beamline and for optimizing the trajectory of the beam at the entry of the plasma-filled drift section.

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Anton D. Stepanov, Erik P. Gilson, Igor D. Kaganovich, Peter A. Seidl, Arun Persaud, Qing Ji, Thomas Schenkel, Alex Friedman, John J. Barnard, David P. Grote. 2017-11-01. Optimizing Beam Transport in Rapidly Compressing Beams on the Neutralized Drift Compression Experiment - II. https://arxiv.org/abs/1711.00539

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