Determination of EID safety distance in pulsed electromagnetic environments (EME)

A possible technique to determine EMC safety distance of electro-initiated devices (EID) is the use of fiber-optic temperature sensors which are thermocoupled to the EID bridgewire [1]. Despite of excellent measurement properties, e.g. temperature range (typ. -100°C - 300°C) and temperature resolution (typ. 0.1°C) [2] theirs basic disadvantage is the limited speed of about 1 ms measurement rate. Therefore, this technique is an ideal candidate for EMC immunity tests in a continuous wave (CW) environment where only steady-state temperature measurements are required but not in a pulsed environment where the measurement rate needs to be much shorter than the thermal time constant of the EID in order to capture maximum EMC generated bridgewire temperature. To overcome the limited measurement rate, radiative temperature measurement techniques seem most promising [3]. This paper investigates the application of an infrared mercury-cadmium-telluride (MCT) based radiation thermometer within a pulsed high-power electromagnetic (HPEM) environment in order to measure induced EID energy and to determine EID safety distance.