one or more piezoelectric elements 303 for example this relationship can be expressed as wherein t pulse represents the time of detonation and t piezo represents the time required for the detonation wave to propagate through the one or more piezoelectric elements 303 the time of detonation t pulse may be represented by t pulse p 2 c 2 vod u00b7 n turns wherein p represents the pitch c represents the circumference of driver 305 vod represents the velocity of detonation of explosive material 311 as discussed above and n turns represents the number of turns of explosive material 311 the time required for the detonation wave to propagate through the one or more piezoelectric elements t piezo may be represented by wherein n piezo represents the number of piezoelectric elements 303 t piezo represents the thickness of each piezoelectric element 303 and v sound in piezo represents the velocity of sound in the material of the piezoelectric elements 303 dielectric portion 313 is provided between driver 305 and receiver 307 about piezoelectric elements 303 to inhibit surface flashover between driver 305 and receiver 307 along piezoelectric elements 303 the occurrence of surface flashover generally inhibits the peak voltage produced by piezoelectric elements 303 and thus is typically undesirable in one embodiment materials suitable for use as dielectric portion 313 are those that are capable of holding off a voltage corresponding to.