For those interested in a setup that can be used as an entrance for incoming colonists that can't be controlled, I made a little example.

I haven't yet tested if it works with embrasures since I tried to include as few mods as possible for easy testing. If the embrasures mod lets the radiation pass through then replace all barricades with those preventing raiders from geting to vital equipment.
If you have any other mod that gives you non traversable tiles but allow the radiation to pass, use those where the barricades are.

The filters are set to double radiation.

The irradiators are intermediate ones, normal ones work as well, they just output less, so you might need to upscale everything for proper results.
The upscaling limit just depends on your map size and resources.

The sandbag is set just before the exit door so that you have plenty of time to press the test run button and hit them while they start climbing over it.
Any method to slow people down when they traverse the choke points between the extenders works, so use whatever works best in your modpack.

The closer they get to the chamber the more radiation hits them.

If you keep radiating downed pawns, limbs can burn off and they bleed out or die from further burn damage.

Depending on the mutations they get, they get downed faster or slower, a lucky one might get a movement boost and make it out alive, RNGesus right in the face for those entering the map.

Screenshot:
https://1drv.ms/u/s!Ak0ZStCdrk7VrFupVz7-cql5MBeD?e=Ay0efb

Sidenote (especially for those with thousands of hours playtime still looking for a magic popping device that could extinguish flames, which for sure is not included in rimworld at all...):
I highly suggest not using wood as in the example.
Or anything else flammable (no chocolate walls that burn Sam!).
Raiders do have a tendency to burn things down, carry explosive stuff or depending on your settings explode on death (possible basegame rimworld setting) which might end in a hefty repair bill.

So that's all I have for you today.
If you do have any comments or questions about this, please put them below.
If you enjoyed it consider giving a polar bear streamer a like, (because he again was the reason for this).
And as usual have a nice day.
(No that outro definetly is not a bad copy version of someone elses outro. I would never get any inspirations about doing things from other people... ofc...)