**Abstract**

Current knowledge on the impact of γ radiation on gas-filled surge arresters (GFSA) is presented. Miniaturization of electronic components has led to their increased vulnerability to overvoltage. The combination of ionizing radiation and voltage surges is present in both space exploration and military applications. Some of the commonly used overvoltage protection components (transient suppressor diodes and metal-oxide varistors) perform poorly under ionizing radiation. GFSA demonstrate improved performance under γ irradiation. Performance of GFSA was tested under neutron + γ radiation, considering the effects of induced radiation. The effects of γ radiation were tested on commercially available GFSA components and on the purpose-built GFSA model. The model was used to measure the prebreakdown current and breakdown voltage of different electrode materials (aluminum, steel, brass) under varying gas pressures, under DC and pulse currents. The improvement of the performance of GFSA due to external γ radiation, combined with other improvements in the design (hollow cathode), can enable the use of GFSA without internal radiation sources in environments where γ radiation is present.

**Keywords:** overvoltage protection, gamma radiation, electromagnetic pulse, power surge, gas-filled surge arrestor

## **1. Introduction**

The advances in complexity and continuous miniaturization of electronic components make them increasingly vulnerable to damage caused by overvoltage events. Modern integrated circuits may suffer temporary or permanent faults even from small overvoltage, due to the size of the internal components in the nanometer range [1, 2]. Overvoltage transients occur in both power and signal lines, due to natural events like lightning strike, normal operation of electric and electronic devices (commutation, powering the devices on or off), failure of equipment or network connections, electrostatic discharge, or the interaction of device/network conductors and electromagnetic fields. Proper design of circuitry protection is essential in preventing temporary or permanent malfunction caused by surge. The combined effects of fast electromagnetic pulse and ionizing radiation present a special challenge to the resilience of electronic components [3].

Depending on their principle of operation and response to voltage transients, overvoltage components can be linear and nonlinear. Linear overvoltage protection components are systems of coils and capacitors assembled into filters of different types. Nonlinear overvoltage protection components come into effect upon the

voltage reaching a certain threshold. Commonly used are transient suppression diodes (TSD), metal-oxide varistors (MOV), and gas-filled surge arresters (GFSA) [4]. The advantages of GFSA compared to the other overvoltage components protection are (1) the ability to conduct high currents (up to 5000 A), (2) low intrinsic capacity (~1 pF), and (3) low costs [5]. The disadvantages of GFSA are (1) practical irreversibility of characteristics after the electric arc effect, (2) delayed response, and (3) unsuitability with respect to environmental protection (if GFSA have a radioactive filling) [6–8].
