Who doesn’t love magnets. I remember as a kid having these two bar magnets and spending hours trying to move them around the kitchen table without actually making them touch (yes, this classifies as fun when you grew up in a small farming town that was 30 miles from the closest movie theater). The ATLAS magnets inspire the same feeling except now these magnets are superconducting and the size of a building (and we generally prefer it when they stay in one place).
ATLAS has two separate magnet systems used for bending the tracks of charge particles in the detector. The magnet surrounding the inner detector is a solenoid (the magnetic field points along the beam pipe). And the magnet for the muon system is a toroid (the magnetic field is circular around the beam pipe). The toroid magnet itself is in three sections: the barrel and two end-caps. And for a sense of size, here is one of the ‘little’ end-cap toroids being transported to the pit many months ago.
Now that we are in the last steps of closing the detector, the final commissioning of the magnets has begun. The plan of the magnet commissioning is to test each of the four magnets separately (the two endcap toroids, the barrel toroid and the solenoid in that order) and then do the full combined test. And since you can’t have people working on other parts of ATLAS when there are large magnetic fields, all the testing is done at night. Over the past few weeks, the tests on one of the end-cap toroids have concluded (successfully!). Unfortunately in the second end-cap toroid, a helium leak was discovered (helium being used to cool the magnets). As a result, tests with this magnet had to be stopped in order to repair the leak. This does not delay us any but it does involve some reshuffling of the magnet commissioning schedule. Tonight will be the first test of the barrel toroid. Fingers crossed that it goes well!
Oh and Spain in an absolutely, spectacular goal in the last minute of injury time beat Sweden to secure their position in the quarter finals!! One step closer to Euro Cup glory!
Tags: ATLAS, commissioning, magnet
