HSD D SENSORS (Free Field)

The free-field HSD (Hollow Spherical Dipole) sensors (Models 2 and 4) measure the normal component of the displacement current (dD/dt). They consist of two hemispherical shells symmetrically attached to a metal conducting surface by dielectric rings. A pressurizing stem and pressure relief valve, located on opposite sides of the output connectors, allow sensor pressurization with high dielectric strength gas (such as SF₆ or N₂) to prevent arcing in intense EMP fields. Free-field HSD sensors are available only in a radial version (see photo), and require no power. Signal output is on 100-ohm twinaxial cable.

Data Specification Sheet