#worldheritagecandidate

Hi, I am in Geneva, I visited CERN. This is the first accelerator they built in 1957, it is called the synchrocyclotron. It was in service until 1990, and after that it could not be visited because of lingering radiation. They opened it to the public some 5 years ago. I visited it as part of the tour.

These tours are free and are great, because you can ask questions. Our guide was a real phsicist working at Cern. I asked how they were able to maintain the accelerator when it was in use, considering how dangerous it must have been to have people working there with so much radiation. He explained that after after the machine was turned off, they had to wait for a while before getting in, they had special protective equipement. Anybody working there had to were a detector that measures how much radiation they were exposed to. When they had to work with a high level, e.g. due to maintenance being required quickly, they worked in short shifts, for example one hour, so that the radiation they were exposed to never got above the legal limit. It is now perfectly safe to visit.