Radiation induced currents in shielded multi-conductor and semirigid cables

We report the results of a study of replacement currents generated in multiconductor and semirigid coaxial cables during irradiation by low (20–100 keV) photons. Short samples (∼ 5cm) of each of thirteen cable types were exposed to filtered radiation from a plasma focus device and the induced center conductor currents were measured for vacuum and air environments. Vacuum responses could be correlated with the magnitude and location of small gaps between the cable elements and the dielectric material, while air responses depended on prior irradiation history, cable geometry, and applied center conductor bias potentials. An analytic computer code has been developed to evaluate the radiation response of these complex cables for a vacuum. Cable air responses are qualitatively discussed in terms of ionized gas kinetics.