CMS gap problem

[YoungPhysicist]

In this picture of CMS, there is a huge gap between the two sides. There is no way that the collision occur directly in midair right?

So is the gap already been sealed? ( which means the picture was taken before it started to operate) Or I am completely wrong?

 

[mfb]

You see CMS during a maintenance phase where the detector was opened to access it. This typically happens every winter, with longer shutdowns (for 1-2 years) every few years.
During collisions it is closed.

 

[YoungPhysicist]

Thanks! I am correct for the first time! By the way, I got another question: when the maintainance is over, are the detector’s two halves brought together to seal the gap or an extra section is removed while mainiainance and installed back afterwards?(Since I didn’t see any sign of some sort of rail mechanism which makes the two halves moveable)

 

[mfb]

They can float on air pads to move together. You can see part of the structure at the bottom right.
https://home.cern/about/updates/2013/03/cms-open-business
http://cms.web.cern.ch/news/heavy-lowering

From a lower point of view: http://www.lhc-facts.ch/index.php?page=cms

 

[YoungPhysicist]

Thanks you so much!

 

[dlgoff]

They can float on air pads to move together. You can see part of the structure at the bottom right.
https://home.cern/about/updates/2013/03/cms-open-business
http://cms.web.cern.ch/news/heavy-lowering

From a lower point of view: http://www.lhc-facts.ch/index.php?page=cms

Some really awesome photos here. Thanks for sharing.