The best way to convey this information is likely through adding a Tips&Tricks entry. We don't plan to add a full slate of them, but an entry for this seems appropriate. To answer your questions, the behavior is as simple as possible — the speed of the particles makes no difference.
It was previously true that quality affected the properties of charging rods, which caused some bad gameplay experiences for players who were unaware. This was likely as the effect was too strong and we might add a very mild effect in future (though again we'd need to add support for explaining this without spoilers). The range of the charging rods drops continuously as the third power of distance, though small effects on particles greater than 25 tiles away are ignored for performance reasons.
The particles from the reactor are unaffected by charging rods because as gamma radiation they don't carry a charge.