Experimental study of self magnetic pinch diode as flash radiography source at 4 megavolt

Abstract

The Self Magnetic Pinch (SMP) diode is a potential high-brightness X-ray source for high voltage generators (2-10 MV) that has shown good reliability for flash radiography applications [D. D. Hinchelwood et al., "High power self-pinch diode experiments for radiographic applications" IEEE Trans. Plasma Sci. 35(3), 565-572 (2007)]. We have studied this diode at about 4 MV, driven by the ASTERIX generator operated at the CEA/GRAMAT [G. Raboisson et al., "ASTERIX, a high intensity X-ray generator," in Proceedings of the 7th IEEE Pulsed Power Conference (1989), pp. 567-570]. This generator, made up of a capacitor bank and a Blumlein line, was initially designed to test the behavior of electronic devices under irradiation. In our experiments, the vacuum diode is modified in order to set up flash radiographic diodes. A previous set of radiographic experiments was carried out on ASTERIX with a Negative Polarity Rod Pinch (NPRP) diode [B. Etchessahar et al., "Study and optimization of negative polarity rod pinch diode as flash radiography source at 4.5 MV," Phys. Plasmas 19 (9), 093104 (2012)]. The SMP diode which is examined in the present study provides an alternative operating point on the same generator and a different radiographic performance: 142 6 11 rad at 1 m dose (Al) for a 3.46 6 0.42 mm spot size (1.4Â FWHM of the LSF). This performance is obtained in a reproducible and robust nominal configuration. However, several parametric variations were also tested, such as cathode diameter and anode/cathode gap. They showed that an even better performance is accessible after optimization, in particular, a smaller spot size (<3 mm). Numbers of electrical, optical, and X-ray diagnostics have been implemented in order to gain more insight in the diode physics and to optimize it further. For the first time in France, visible and laser imaging of the SMP diode has been realized, from a radial point of view, thus, providing key information on the electrode plasmas evolution, responsible for the gap closure. V C 2013 AIP Publishing LLC. [http://dx.

The impact of plasma dynamics on the self-magnetic-pinch diode impedance

“…These results are in agreement with measurements by Etchessahar et al, which yielded 3-5 cm/ls from the anode and 1-3 cm/ls from the cathode for a 12.5-mm cathode diameter. 25 They are also in agreement with the results of The plasma diagnostics (along with the simulation results in Sec. IV) indicate that plasma expansion into the AK gap is sufficient to explain the nominal impedance lifetime of the SMP diode.…”

Contribution of Electromagnetic Perturbation to the Transient Response of an Electronic Circuit Exposed to a High Multi-MeV X-Ray Flux

“…E XPERIMENTS involving x-ray interaction with matter arouse increasing interest for a broad range of applications: electronic equipment hardening within ionizing environments [1]; [2], in particular Transient Radiation Effects on Electronics (TREE) and System Generated Electromagnetic Pulse (SGEMP), electrostatic discharges [3], x-ray radiography [4], etc.…”