No, sticking your thumb or any body part inside a particle accelerator when it is operating would not give you superpowers. In fact, it would be extremely dangerous and potentially fatal. Particle accelerators generate extremely high-energy particle beams, often traveling near the speed of light. These beams can be harmful or lethal to living tissue.
Particle accelerators are designed to be operated in controlled environments with strict safety measures in place. Access to the accelerator components is restricted to trained professionals who follow stringent safety protocols. Direct contact with the accelerator or its beam could result in severe injury, including burns, radiation exposure, or damage to biological tissue.
If you have any curiosity or interest in particle accelerators, I would recommend studying them through appropriate educational channels and respecting the safety guidelines associated with these complex scientific instruments.