working a beam shift

As I mentioned in my previous post, I was going to be  working the night shift on a "test beam". Would have posted sooner but it turns out I have to upload pictures using the hotel internet, which is extremely slow. I finally have an account at CERN, but am still waiting for my laptop to be registered and therefore able to run on their wireless, which is much faster. (Remember, CERN is where the internet was invented). I am hopeful to be all set by the time I leave next week.

If you are interested in CERN and the experiment I am remotely involved with, here are some links"

http://public.web.cern.ch/public/ Public web site and general information.

http://cms.web.cern.ch/cms/index.html Information about the CMS experiment, which the Princeton group is involved with. One objective is to detect the Higgs boson.

http://www.youtube.com/watch?v=f6aU-wFSqt0 The Large Hadron Rap. Entertaining and somewhat informative. My students enjoyed it when it came out a few years ago.

Right now the Princeton group and other institutions involved in this international collaboration is running some tests on a detector that will be used in the Compact Muon Solenoid (CMS) in a few years. The idea is to duplicate the conditions in the Large Hadron Collider using a test beam, to test and calibrate the equipment.

The protons that are flying around in the LHC are actually produced in a smaller accelerator, sped up to a certain energy and then injected into the LHC, where they are then further accelerated to very high energies (duplicating the conditions of the early universe, producing the Higgs and other particles, creating black holes, quark-gluon plasma, yada yada etc.). The tests are perfomed at the CERN Prevesson site, using one of the start up accelerators. (At one time this was THE particle accelerator). Some of the protons are injected into the LHC, and some are diverted for the test beam. So as a "beam shifter" I was "working" at the Prevesson site, helping a group from Turkey test their detector.

So here I am, looking pretty good for 3 am! See all of those wires? I know what every single one is for. Not! And I thought there were a lot of cables laying around when the band plays!

Looks worse than the recording studio where the Modulators recorded their album.

So what happens is that after the protons are accelerated they slam into a target (by the concrete on the right in the picture) and stop. Other particles are then produced, depending on the target material (some kind of metal). For the first part of the night we used a target that produced muons. After that we used another that produced pions. In each case, the particles come through the bluish tube (You can't see them, but they are there. That's why we wear radiation badges).

The muons then go through the detector shown below, which has a bunch of metal plates which stop the muons at different distances depending on their speed. This is actual a massive machine that is moved around by huge motors on a track, like a rail car. It was moved out of the way of the beam for the pion experiment.

 

The muons that are not stopped are detected in another instrument about 10 feet past the one pictured above (the pions had to go through about 1 foot of iron first). I don't have a good picture of that instrument but it is just a metal box with photomultiplier tubes inside, sitting on top of a big jack stand so the position can be changed. For most of the night we would just take data until 10000 or so particles were detected, then move the box and did it again. Very exciting. But I managed to stay up until 8:30 am!

Painstaking work, but in the end, this is what it's all about.

 

Will post again soon.