SGEMP-Induced Transfer Admittance Coupling in Cable Bundles

One of the ways energy can couple to the inner wires of an electrical cable bundle exposed to nuclear x-rays involves the transfer admittance of the inner bundle shields; we present an analysis of this coupling mode, in which the electric field induced by SGEMP between the outer and inner shields couples to the wires via small apertures in the inner shields. Using an equivalent circuit model, the transfer admittance-coupled response is calculated for a generic cable bundle, and compared with the direct injection response. Sensitivity of the response to significant cable parameters is investigated, and limitations of the model are discussed. It is shown that an insulating tape wrap adjacent to the outer shield, often present as a fabrication aid, reduces the response by about an order of magnitude.