I had an idea about a weapon which kills people using radioactivity bursts:

**Weapon function:** It kills a specific person with radioactivity. It should be as selective as possible. Some wider range is expected, but should be as low as possible.

**Requirements for the weapon:**

* Should be wearable by one person.
* Should be safe to use
* Should be quick and allow more than one shot
* Should be built using today's technology. No unobtainium please.
* Range at least 100 metres. I would like to have a rather ranged weapon

Can you help me with designing this weapon? Also, is it even feasible to build?