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Plasma spectroscopy diagnostics in pulsed-power X-ray radiography diode research

Johnston, Mark D.; Hahn, Kelly D.; Rovang, Dean C.; Portillo, Salvador; Maenchen, John E.

Spectroscopic investigations in the visible and near UV are underway to study plasmas present in X-ray radiography diodes during the time of the electron beam propagation. These studies are being performed on the RITS-3 accelerator (5.25 MV and 120 kA) at Sandia National Laboratories using several diode configurations. The proper characterization of the plasmas occurring during the time of the X-ray pulse can lead to a greater understanding of diode behavior and X-ray spot size evolution. By studying these plasmas along with the use of selective dopants, insights into such phenomena as impedance collapse, thermal and non-thermal species behavior, charge and current neutralization, anode and cathode plasma formation and propagation, and beam/foil interactions, can be obtained. Information from line and continuum emission and absorption can give key plasma parameters such as temperatures, densities, charge states, and expansion velocities. This information is important for proper modeling and future predictive capabilities for the design and improvement of flash X-ray radiography diodes. Diagnostics include a gated, intensified multichannel plate camera combined with a 1 meter Czerny-Turner monochromator with a multi-fiber spectral input, allowing for both temporal and spatial resolution. Recent results are presented.

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TYPE Conference YEAR 2005
OSTI

Advances in pulsed-power-driven radiography system design

Maenchen, John E.; Cordova, S.; Bohlken, Fawn A.; Hahn, Kelly D.; Jaramillo, Deanna M.; Molina, I.; Portillo, Salvador; Madrid, Elizabeth A.; Rovang, Dean C.; Sceiford, Matthew S.

Flash x-ray radiography has undergone a transformation in recent years with the resurgence of interest in compact, high intensity pulsed-power-driven electron beam sources. The radiographic requirements and the choice of a consistent x-ray source determine the accelerator parameters, which can be met by demonstrated Induction Voltage Adder technologies. This paper reviews the state of the art and the recent advances which have improved performance by over an order of magnitude in beam brightness and radiographic utility.

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TYPE Conference YEAR 2004
OSTI

RITS-3 self-break water switch maintenance

Portillo, Salvador; Hahn, Kelly D.; Molina, I.; Cordova, S.; Maenchen, John E.

The radiographic integrated test stand (RITS-3) is a 5-MV, 160-kA, 70-ns inductive voltage adder accelerator at Sandia National Laboratories used to develop critical understanding of x-ray sources and flash radiographic drivers. On RITS-3 three pulse forming lines (PFLs) are used to drive three inductive voltage adder cavities. Each PFL contains a fast-pulse-charged, self-breakdown annular water switch that is used for initial pulse shaping and timing. Low loss in the switches combined with good synchronization is required for efficient operation of the accelerator. Switch maintenance is closely monitored over time to determine the effects of wear on switch breakdown performance.

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TYPE Conference YEAR 2004
OSTI
Results 76–100 of 102
Results 76–100 of 102