Matter and Radiation at Extremes, Volume. 7, Issue 1, 016901(2022)
A portable X-pinch design for x-ray diagnostics of warm dense matter
Fig. 1. (a) CAD model of the entire external housing with a 350 mm long transmission line together with a circular entry port (1) for high-voltage charging cables and small circular entry ports (3) for triggering cables coupled into the switches. (b) Cross-section of Dry Pinch I containing the LTD bricks (2). The capacitors and switches are not to scale. (c) Close-up of the transfer plate zone, including the transfer plate connecting the two capacitors (4), a high-density polyethylene insulating plate (5), a gently converging current plate (6), a magnetically insulating transmission line (7), and a recess for a nonintegrating Rogowski coil (8). (d) CAD model of the five-channel dry air ball gap switch used to trigger Dry Pinch I. (e) Cross-section of the final part of the transmission line where the X-pinch load is mounted. The gap located in the cathode at the center of the diagram hosts the load-locking ring [shown in (f)]. It is possible to use different designs for the load section with different A–K gaps or shapes/numbers of output windows. (f) CAD model of the mounting mechanism, including the cathode (9), the load-locking ring (10), the X-pinch load (11), and the top anode plug (12). The direction of electron flow within the device is indicated by red arrows before the load and by blue arrows after the load.
Fig. 2. Equivalent circuit diagram of the X-pinch and its respective components. The inductance of the MITL was modeled as arising from two coaxial cylinders discharging in parallel.
Fig. 3. Short-circuit current measurement with the load replaced by an M6 bolt. Nonintegrated Rogowski data were measured by a coil located within the recess of the Dry Pinch I top plate (depicted in blue). The oscillatory signal observed at the beginning of the Rogowski data is the noise caused by the switch firing. The red line corresponds to the current calculated as a cumulative integral of the nonintegrated Rogowski data.
Fig. 4. The x-ray sensitivity of the Fuji-IP MS image plate (plotted in black) and the sensitivity of the Kodak DEF (plotted in red). Data are taken from experiments and modeling by Meadowcroft
Fig. 5. Transmission profile of metal filters applied to (a) a stainless steel pinhole array target and (b) diamond photoconductive detectors and silicon x-ray diodes.
Fig. 6. Temporally gated optical emission emanating from the load captured every 20 ns with 5 ns exposure time. The initial frames show wire expansion followed by magnetic compression and a micropinch formed at
Fig. 7. Timing of all data in plots (a)–(d) is offset such that the current waveforms of all measurements coincide at 5 kA. (a) Current derivative time series measured by a nonintegrating Rogowski coil and smoothed by a 100-point (20 ns) moving-average filter. (b) Numerically integrated current waveforms of 17 back-to-back shots using the X-pinch driver with 4 × 30
Fig. 8. Images of a 4 × 30
Fig. 9. (a) An x-ray radiograph of a USAF target covered by a 12.5
Fig. 10. Radiograph of an aluminum step-wedge spanning thicknesses from 100 to 1500
Fig. 11. Measurement of the X-pinch emission for silver and tungsten wire loads by a convex LiF spectrometer recorded on image plates. The LiF crystal was covered by a 12.5
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J. Strucka, J. W. D. Halliday, T. Gheorghiu, H. Horton, B. Krawczyk, P. Moloney, S. Parker, G. Rowland, N. Schwartz, S. Stanislaus, S. Theocharous, C. Wilson, Z. Zhao, T. A. Shelkovenko, S. A. Pikuz, S. N. Bland. A portable X-pinch design for x-ray diagnostics of warm dense matter[J]. Matter and Radiation at Extremes, 2022, 7(1): 016901
Category: Radiation and Hydrodynamics
Received: Jun. 14, 2021
Accepted: Oct. 19, 2021
Published Online: Apr. 6, 2022
The Author Email: Strucka J. (jergus.strucka15@imperial.ac.uk)