The electromagnetic calorimeter is now fully installed but there’s still work to do before we start running. We now have to make sure we’re able to read all of the data. I’ve spent most of the last week in, on, and next to ALICE troubleshooting (along with several of my colleagues working on the calorimeter.) Here I am sitting inside the magnet on top of the support structure next to the front end electronics (the boards that read out the data) for the calorimeter. I’m on the phone with someone upstairs who’s trying to take a pedestal run to see if we’ve fixed a problem reading out data from one of the new supermodules. (A pedestal run is a run you take without proton-proton or lead-lead collisions to see what the background in your detector is. It’s useful for troubleshooting because the detector has to send data.)
Now that we’re getting close to the start of the run, they’re putting the concrete shielding in. In total 30 or 40 tons of concrete blocks sit above ALICE. Here you can see one of the last blocks going in:
And just to go along with the preposition theme, here’s a picture under ALICE (in the magnet but under the TPC, TRD, and TOF):
Tags: ALICE, detector, heavy ion physics
Hi Christine,
I just found your blog today and it’s very fascinating to have such an inside view of the LHC- I’ve tried to keep up to date about the developments there pretty much form the start. I knew that the accelerator only recently restarted after the winter shutdown, and that some overhaul was to take place during the shutdown – but I thought it to be rather minor. So I’m really wondering about your 2nd picture of the huge concrete slab, and my question is about this. Had the concrete shielding been damaged and had to be renewed, or had it been taken out in order to access the detector, or for some other reason?
Thank you in advance – you’re doing great work there!
Hi Diana
Nothing was damaged – the shielding was removed because over the winter “break” we installed additional sub-detectors (in particular, my dear electromagnetic calorimeter). The whole detector is covered in concrete blocks during the run. The shielding was in the way of the path we had to use to lower the detector in. So this was all part of the plan.
Thanks!