I introduced you to the ALICE electromagnetic calorimeter (EMCal) a while ago, and told you about some additional training I had so that I could work on the detector after the EMCal is physically installed. Over the winter shut down – right now – the EMCal is being installed inside ALICE.
There are several steps in this process. First the EMCal was assembled, partially calibrated, and tested – this was done in November. There were several stages of testing. We tested that each individual cell works. We tested that each individual electronic card for reading out the data works. We assembled everything exactly how it would be installed inside ALICE and tested it again, making sure that all of the parts (including the wires) worked together. We partially calibrated the detector by taking data on cosmic rays. We’ve had all of the six supermodules we’re adding waiting at CERN until we could get access to ALICE to install them.
Now they’re physically installing the supermodules and our amateur EMCal documentarian, Federico, has taken some videos of the process. (It might help to go back to this post, where I introduce each of the detectors and explain what they do, and this post, where I show you some pictures of each of the detectors. Then maybe you can identify the different parts of ALICE in the video.) Note the action in the videos is very slow because it’s very important not to damage anything while installing the detector.
The first step is to put the supermodule in the EMCal insertion tool. This is a specialized device for installing EMCal supermodules. Here you can see a video of that step:
And then once the supermodule is in the insertion tool, it gets installed in ALICE:
[youtube 0es9Qcdj-H8]
And now some gratuitous cool pictures of the process:
ALICE ready for the installation of EMCal supermodules
Looking up from the cavern. We sit at the top when we take data and the detector is far below us. The EMCal supermodules have to be lowered down.
Checking everything twice to make sure there are no mistakes.
Getting the EMCal insertion tool ready for a supermodule
Getting ready to strap the support onto the supermodule
Sliding the support onto the supermodule
Now it’s in and they’re strapping it onto the crane
Up goes the supermodule…
…and into the insertion tool.
And it’s rotated to the correct angle…
Waiting on the support structure in ALICE to make sure it goes in properly…
Get it in the right position…
Now loosen it from the EMCal tool and in it goes!
And now we do the next one.
Many thanks to Federico for the great pics!
Tags: ALICE, detector, heavy ion physics
