In the Large Hadron Collider (LHC), particles are accelerated in opposite directions in separate beam pipes. These beams of particles circulate in a circular path in opposite directions and are made to intersect at specific points where the detectors are located. When two particles collide, they do so head-on rather than from behind.
The LHC operates with two counter-rotating beams, typically consisting of protons or heavy ions. These beams are guided by powerful magnetic fields to travel in circular paths in opposite directions. When the beams intersect at designated collision points, the particles within the beams can collide with each other.
In the case of a particle moving in one beam and colliding with a particle from the other beam, it would be a head-on collision, not a collision from behind. The beams are carefully controlled and directed to ensure that collisions occur at these interaction points. The particles within the beams are traveling at extremely high speeds, close to the speed of light, so their collisions are typically treated as head-on interactions.
It's important to note that the LHC is designed with sophisticated systems to prevent unwanted collisions or accidental collisions between particles in the same beam. The beams are focused and guided to ensure that collisions occur only at the desired points and with the desired particles. Safety measures and strict protocols are in place to ensure the controlled operation of the accelerator and to protect the integrity of the experiments and the equipment.