Experimental development of rod pinch diode radiographic source using modified Kali 1000 pulsed power system

• Main Authors: Satyanarayana, N., Basu, Shibaji, Rajawat, R. K., Rao, A. Durga Prasada, Mittal, K. C.
• Format: Conference Proceeding
• Language: English
• Subjects: Anodes; Cathodes; Electron beams; Graphite; Impedance; Radiography; Tungsten
• ISSN: 1093-2941
• DOI: 10.1109/DEIV.2014.6961688

This paper highlights the development of Rod Pinch (RP) diode for flash X-ray generation as intense radiographic source at BARC, Vizag. The typical RP diode employed used a small diameter (1-2 mm) anode rod extended through a cathode circular aperture (5-6 mm inner diameter). The diode chamber is maintained at 10 -5 Torr vacuum by a rotary backed diffusion pump. Experiments performed on a modified Kali 1000 Pulsed Power System (300 kV, 30 kA, 100 ns) were aimed at optimizing the source by maximizing the figure of merit (dose @ 1m in rad/ spot diameter 2 in mm 2 ) with minimizing of the diode impedance. The typical electron beam parameters used in the experiments are 240-270 kV, 20-25 kA, 100 ns, with a few hundreds of kA/cm 2 current density. The optimization resulted in a configuration with tungsten anode rod having dimensions of a 1.6 mm diameter, tapering extension length 5-25 mm beyond the graphite cathode aperture (Cathode disk ID = 5 mm, thickness = 3mm) to produce a radiation dose of 150-200 milli rad at 1 m distance having an estimated spot-size of 1-2 mm. The radiation emitted from a rod-pinch diode is measured using Thermoluminscence dosimeters (TLDs) at an angular interval of 15° on either side of the rod in horizontal and vertical plane.