Allow me to add some details (I was in a hurry when I threw the question up earlier).
The "surges" in question are not incidental or environmental, but an integral part of the devices function, the device being a Geiger counter.
For those that are not familiar with how Geiger counters work, there are essentially two sides to the electronics package: the high voltage side which loads the Geiger-Mueller tube at 400-1400v and a low voltage side that detects when the high voltage side fires upon the tube being penetrated by a ray or particle of ionizing radiation. The low voltage side then counts it, averages it, turns it into a LED blink or a "click" in a speaker, whatever you want it to.
Usually, there are some HV diodes and other circuitry involved in keeping the high voltage side from leaking over and blowing up the low voltage side, but a common failure mode in some Geiger counters is for that circuitry to break down, resulting in blown transistors and such,
I was beginning to think in terms of using an optocoupler for that purpose as a way of making the HV and LV sides completely isolated from one another. If there is zero electrical interface between the two, that cant happen any more, can it?
Anyway, that is what I was thinking. Thanks for the feedback.