Yesterday’s big event was the LHC official inauguration, at which I was present to represent CMS to the various delegations. This was a great experience, it is very interesting to meet the people who make decisions about how we are funded and explain (hopefully in a successful way) why the studies we will do at the LHC are essential for the understanding of how nature and the universe work. (more…)
Currently I am sitting at Geneva airport waiting for my plane to finally leave for Amsterdam. Looking east I see something the average cernoise is always happy to see: First snow on the Jura.
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This just came in from the CERN directorate:
LHC re-start scheduled for 2009
Geneva, 23 September 2008. Investigations at CERN following a large helium leak into sector 3-4 of the Large Hadron Collider (LHC) tunnel have indicated that the most likely cause of the incident was a faulty electrical connection between two of the accelerator’s magnets. Before a full understanding of the incident can be established, however, the sector has to be brought to room temperature and the magnets involved opened up for inspection. This will take three to four weeks. Full details of this investigation will be made available once it is complete.
“Coming immediately after the very successful start of LHC operation on 10 September, this is undoubtedly a psychological blow,” said CERN Director General Robert Aymar. “Nevertheless, the success of the LHC’s first operation with beam is testimony to years of painstaking preparation and the skill of the teams involved in building and running CERN’s accelerator complex. I have no doubt that we will overcome this setback with same degree of rigour and application.”
The time necessary for the investigation and repairs precludes a restart before CERN’s obligatory winter maintenance period, bringing the date for restart of the accelerator complex to early spring 2009. LHC beams will then follow.
Particle accelerators such as the LHC are unique machines, built at the cutting edge of technology. Each is its own prototype, and teething troubles at the start-up phase are therefore always possible.
“The LHC is a very complex instrument, huge in scale and pushing technological limits in many areas,” said Peter Limon, who was responsible for commissioning the world’s first large-scale superconducting accelerator, the Tevatron at Fermilab in the USA. “Events occur from time to time that temporarily stop operations, for shorter or longer periods, especially during the early phases.”
CERN has received similar words of support from several laboratories, including Germany’s DESY, home of the HERA superconducting particle accelerator, which ran from 1992 to 2007.
“We at DESY have been following the commissioning of the LHC with great excitement and have been very impressed with the success of the first day,” said Albrecht Wagner, DESY Director. “I am confident that our colleagues at CERN will solve the problem speedily and we will continue to support them as much as we can.”
I was just handed an ATLAS postcard with a graphical display of one of the first debris events on it.
All I could think was: Wow, those guys are fast!
If the collimators are open and the beam passes through the detector, you can actually see a lot less than when you break the particle beam with your big block of Tungsten (the material that the collimators are made of).
So… here you see what we see when beam goes through our detector. Practically nothing, which is good as there are no collisions at the moment. The only thing that the beam can collide with is the few remaining gas atoms in the beam vacuum (no vacuum is perfect). These occasional beam gas with beam-collisions are much cleaner and what you’re looking at here is a muon flying along the beam (the collision probably actually was some time before the actual detector) and being detected by our muon detectors.
This morning, at about 9:55 CERN time, the LHC beam was dumped on a
collimator just upstream of CMS. This is when we first saw for the
first time the beam activity in the detector, a picture is attached.
What you see is the debris of the beam particles hitting the collimators. The resulting shower then produced a lot of activity in our hadron calorimeter (blue) and some hits in our muon system (small green rectangles). And all of those dirty messy particle showers from three different angles, which is why we have three different figures for the same events. The inner detector was turned off due to the beam still being very unstable and it can actually be damaged easily by randomly flying particles.
I am so excited! I am currently in the CERN media center where things are buzzing with journalists from all over the world! Before I forget to brag about the fact that the google home page is LHC themed today!
The LHC startup is getting closer and closer. A few previous blog entries already informed you that there was a successful insertion of beam into the LHC. This is of course great news, but means that the testing and final preparations of the detectors has now become serious business. As the CMS pixel detector was planned to be installed as one of the final components before the first beam was delivered, we are very much under pressure to be ready in time. 
You can read that as ‘continuously on shift until things are stable enough to be run by non-experts’. This also explains the lack of blog entries by me and some of the other people working closely on the detector, at the moment the pressure is really on and the detector comes first!
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Today’s post is not about physics, but is definitely related to something particle physicists do quite frequently: travel.
The trip is to Amsterdam, something I do monthly as I have many friends and all my family there. This time it is a more than normally joyous occasion, a friends wedding. And just like every month, I spend a considerable amount of time trying to arrange transportation. As usual there are two things to consider: cost and time to take off work. The distance is almost 1000 kilometers (over 600 miles). Besides driving, which is not an option as I do not have a car (it would be unmaintainable as there is no parking in Geneva and besides that the public transport is excellent in Switzerland, and considering the high gas prices in Europe it will not be very competitive anyway) there are three travel options. And I would like to share the results of my search with you as it’s not only unexpected but I also do not understand the why: (more…)
As most of you are by now hopefully aware, Euro2008 (the European soccer championship for country teams) is currently taking place in Austria and Switzerland. Just like Monica and Pam I am having substantial problems not getting distracted by this extravaganza. Being Dutch doesn’t help, the Netherlands is performing much better than anyone expected, including the Dutch themselves. This leads to almost surreal celebrations. Let me give you an example:
As I walk down the CERN restaurant terrace I feel refreshed. Not necessarily because summer just refuses to start here and we get gloomy clouded skies with thunder storms instead, although I can assure you Geneva thunder storms are very refreshing. No, I’ve spent two days on a very muddy field on the border of Germany, Belgium and the Netherlands, at one of Europe’s oldest outdoor music festivals. Not only was the weather significantly better than expected, I also got to enjoy some of my favorite bands and got to spend quality time with some of my friends.
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