First of all, I’m sorry if my question would be very stupid, I’m not really into all of this stuff yet so I’m asking.

I’ve been thinking lately about one thing. Is it possible to use a black hole as a particle accelerator? Well, if we had one, very small black hole, could we calculate the trajectory and launch some particles? But wouldn’t the relativity theory make the particles move ‘slower and slower’ coming closer to the black hole? What am I misunderstanding?