I’m only a physics enthusiast, so I may be off on specifics, but yeah it should be on/off. These things aren’t dealing with large particles as far as atoms go - you’re looking at more like protons, electrons, etc. After the collision particles will typically decay very quickly, so you’ll get all kinds of radiation, but the products of the decay are very short lived. You will sometimes have unstable isotopes created in the walls of the collider, but they’re designed to be very safe and avoid that. And even if there was no thought given to the wellbeing of the ferret, humans work on and in colliders, so they need to be safe - not to mention how radioactivity could potentially throw off results.