Optical Spectroscopy Results for the Self-Magnetic Pinch Electron Beam Diode on the RITS-6 Accelerator

Technical Report · Fri Jun 01 00:00:00 EDT 2012

DOI:https://doi.org/10.2172/1118170· OSTI ID:1118170

Johnston, Mark D. ^[1]; Oliver, Bryan Velten ^[1]; Hahn, Kelly Denise ^[1]; Droemer, Darryl W. ^[2]; Crain, Marlon D. ^[2]; Welch, Dale Robert ^[3]; Yitzhak, Maron ^[4]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.
2. National Security Technologies, LLC. (NSTec), Las Vegas, NV (United States)
3. Voss Scientific, LLC, Albuquerque, NM (United States)
4. Weizmann Inst. of Science, Rehovot (Israel)

Experiments have been conducted at Sandia National Laboratories' RITS-6 accelerator facility [1] (operating at 7.5 MV and 180 kA) investigating plasma formation and propagation in relativistic electron beam diodes used for flash x-ray radiography. High resolution, visible and ultraviolet spectra were collected in the anode-cathode (A-K) vacuum gap of the Self-Magnetic Pinch (SMP) diode [2-4]. Time and space resolved spectra are compared with time-dependent, collisional-radiative (CR) calculations [5-7] and Lsp, hybrid particle-in-cell code simulations [8,9]. Results indicate the presence of a dense (>1x10¹⁷cm^-3), low temperature (few eV), on-axis plasma, composed of hydrocarbon and metal ion species, which expands at a rate of several cm/s from the anode to the cathode. In addition, cathode plasmas are observed which extend several millimeters into the A-K gap [10]. It is believed that the interaction of these electrode plasmas cause premature impedance collapse of the diode and subsequent reduction in the total radiation output. Diagnostics include high speed imaging and spectroscopy using nanosecond gated ICCD cameras, streak cameras, and photodiode arrays.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1118170
• Report Number(s): SAND-2012-4646; 498580
• Country of Publication: United States
• Language: English