Questions and answers: accelerators

1. What is a collider?
   A collider is a particle accelerator that makes beams of accelerated particles to collide with each other.
2. How is a particle made to accelerate and travel in a curved trajectory?
   To accelerate a particle, electrical fields are used. To make the particles bend one uses magnetic fields.
3. How are particles accelerated? From the start to the end.
   Electrons are set free from a metal wire. Some of these electrons are made to collide with a heavy metal target, thereby creating positrons. The positrons and some of the initial electrons are then accelerated in a chain of accelerators, and finally they are guided into collision course.
4. What differences and similarities are there between the LEP and the LHC accelerators?
   Except that both are colliders, the only similarity is that LHC will be built in the same tunnel as LEP, and therefore they will have the same size. The two big differences are that LHC will accelerate protons instead of electrons and positrons, and that LHC will give the particles a much higher energy compared to LEP (14 TeV compared to 0.2 TeV).
5. Why are neutrons not accelerated at LEP?
   The neutron has no electrical charge, which makes it impossible to accelerate it. Even if it was possible to accelerate neutrons, LEP could not deliver enough energy to accelerate neutrons to any interesting speed, since they are too heavy.