Technique for inferring angle change as a function of time for high-current electron beams using a dose-rate monitor array

Journal Article · 18 November 2019 · Review of Scientific Instruments

DOI: https://doi.org/10.1063/1.5110413 · OSTI ID:1575256

Renk, Timothy Jerome  ^[1]; Weber, Bruce V. ^[2]; Rittersdorf, I. M. ^[2]; Webb, Timothy Jay ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2. Naval Research Lab., Washington, D.C. (United States). Plasma Physics Div.

Intense electron beams striking a high-atomic number target produce high-output pulsed photon fluxes for flash x-ray experiments. Without an external guide field, such beams are subject to the dynamics of high-current electron beam propagation, including changes to electron trajectories either from self-fields or from development of beam instabilities. The bremsstrahlung output (dose-rate) scales approximately as IV^x, where I is the beam current, V the electron energy, and x is in the range 2.0–2.65 and depends upon the electron angle on the converter. Using experimental beam data (dose-rate, I and V), this equation can be solved for x, a process known as “inverting the radiographer’s equation.” Inversion methods that rely on thermoluminescent dosimeters, which are time-integrated, yield no information about evolution of the electron beam angle in time. We propose here an inversion method that uses several dose-rate monitors at different angles with respect to the beam axis. By measuring dose-rates at different angles, one can infer the time-dependent beam voltage and angle. Furthermore, this method compares well with estimates of corrected voltage and results in a self-consistent picture of beam dynamics. Techniques are demonstrated using data from self-magnetic pinch experiments at the RITS-6 facility at Sandia National Laboratories.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1575256
• Alternate ID(s): OSTI ID: 1574544
• Report Number(s): SAND--2019-5559J; 675620
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 11 Vol. 90; ISSN 0034-6748
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English