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Adam Yurkewicz | USLHC | USA

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LHC update

Monday, December 1st, 2008

In addition to the information contained in Seth’s post, there was another interesting LHC update today at the ATLAS Week. Last week, there was a talk that caused a lot of conversation among the physicists that implied the CERN management was considering the possibility of not having any beam at all in the LHC in 2009.  During the talk today, the statement was made that there are definitely no plans being considered to not try for collisions in 2009.

The schedule in this talk calls for the machine to be cold at the end of July.  Of course, something could go wrong with the repairs, but every effort is being made to have collisions next year.  The collision energy next year would be at a maximum of 10 TeV (14 TeV is the design) and possibly lower.

Some other interesting points in the talk:

  • Approximately 100 people from CERN (and contractors) are already working on the repairs.
  • 39 dipoles & 14 “short straight sections” in the incident area and in the buffer zone around it will be removed and repaired or replaced.  About 20 new dipoles will be installed before the end of the year.
  • 12 dipoles and 6 SSSs have already been transported to the surface.  The first replacement dipole was transported underground on Saturday.  Some neat pictures here.
  • Techniques have been developed to spot resistive splices, the original cause of the disaster.
  • The anchoring of some of the cryostats will be reinforced, so they wouldn’t be able to move in future incidents.
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Happy Thanksgiving!

Friday, November 28th, 2008

Happy Thanksgiving from CERN! As you can see from the picture, many of us got together yesterday to celebrate (people from the CMS and ATLAS experiments even ate together in the spirit of Thanksgiving).
Holidays here always feel a little different, mainly because US holidays usually aren’t holidays here.
This one wasn’t exactly your typical Thanksgiving, mainly because most of us worked during the day, and we had the dinner at night. There wasn’t much evidence that it was Thanksgiving at CERN, but our celebration felt pretty authentic. We had just about all the necessary foods (no cranberry sauce), incuding not one but two turkeys. And we streamed NFL football live!
The biggest negative about working abroad is being away from family and friends, and that is especially true on Thanksgiving. But yesterday we did a pretty good job of re-creating the family atmosphere, and a phenomenal job of re-creating the feeling of having eaten way too much. Waaaay too much.

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Ouch

Tuesday, November 18th, 2008

The price tag for the LHC repairs was in the newspaper. And the official estimate for beam back in the LHC is now “summer” instead of “spring”. I remember the day the accident happened and I heard a rumor that the LHC would be down for 3 months.  It seemed too bad to be true.  Things have only gotten worse since then as more has been learned about the extent of the damage.  It is disappointing, but hopefully at this time next year we will be drowning in data.

In the mean time, people on the detector side are still quite busy. There are plenty of repairs to do, analysis of cosmic ray data, physics studies and software improvements, and getting better prepared for next year’s data.  But everyone wishes we had just a little collision data to enjoy during the long winter nights.

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LHC in the news

Friday, November 7th, 2008

Even though there won’t be any discoveries for a while, the LHC remains in the news.  It was named the #5 best invention of 2008 by Time magazine.  Not bad, although looking at the top 4:

  • 1. The Retail DNA Test
  • 2. The Tesla Roadster
  • 3. The Lunar Reconnaissance Orbiter
  • 4. Hulu.com

I am a little disappointed.

Okay, at-home genetics (#1), electric cars (#2), and movie downloading web sites (#4) are more useful right now than the LHC, and space missions (#3) produce better images, but I don’t think any of them will have as large an impact long-term.

Although some people think the impact is already being felt.  When analyzing the election results on his comedy show, Stephen Colbert said (1:20 mark or so) he believed that the LHC “jolted us into a parallel universe that is exactly like our own, only Barack Obama is president and the Phillies are world champions.”  And he may be right.

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216 million events

Monday, October 27th, 2008

Today marked the end of the combined running (using the entire detector as it would be for recording collisions data) of the ATLAS detector for 2008. Unfortunately the running didn’t include any time with collisions this year, but as you can see in the image, we have still been recording tons of data recently.  The blue line is the sum of all the events recorded by ATLAS in days since September 13.  “Events” are just snapshots taken at one moment by the detector.

The last few weeks were devoted to getting as much high quality cosmic-ray data recorded as possible, while the detector was still “all in one piece”.  Over the next few months, there will still be data recorded, but more often with a few pieces at a time, and usually some piece off for maintenance at any moment.

The data that was just recorded will be analyzed for the next few months to calibrate the detector and get ready for collisions in 2009.  The total number of events recorded in the last 44 days was 216 million.  That works out to about 57 events recorded per second, every second of the day, for 44 days straight.  Each event is a megabyte or so, so we are talking hundreds of terabytes of data written out.  You can also see, it wasn’t a constant 57 events per second.  There was a week where about half the total data was recorded that was much faster during some special running to accumulate data for the inner detector calibration.

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Life in the Fishbowl

Wednesday, October 15th, 2008

There has been quite a lot of activity at the ATLAS site this week. I don’t mean the physicists, I mean the construction workers. The result is a new entrance area to the building that houses the ATLAS control room, just in time for the big inauguration next Tuesday.

The new entrance area has mostly glass walls, and you can see in the photo (thanks Richard!) that it looks into the ATLAS control room (also visible on this web cam which updates every 5 minutes).  You might also see that not only does it look into the ATLAS control room, it is approximately 3 feet from where I usually sit.  This means visitors will be staring at me and my colleagues from 3 feet away while we work.

For most people in the control room, this fishtank configuration is an improvement because there have often been visitors walking through the control room taking flash photographs (I assume this means visitors will no longer be allowed in).  For those of us at the liquid argon calorimeter desk, it might be a little distracting.  But maybe they will feed us…

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This Week at ATLAS

Saturday, October 11th, 2008

I was on shift all week at ATLAS.  When I signed up for these shifts, I thought perhaps we would be looking at collisions, but well, things weren’t quite that exciting.  Actually, for me they weren’t that exciting at all since I was at the Liquid Argon Calorimeter desk, and our detector wasn’t being read out for most of the week.  This was to allow ATLAS to write out more data in a short time.  The calorimeter data volume is quite large and our calorimeter wasn’t the focus of these studies.  Seth was sitting at the Pixel desk, and things seemed a bit more interesting there as they were recording lots of tracks.

ATLAS was recording cosmic muon data this week.  I heard there were at least 50 million events recorded, some with the magnets on and some with the magnets off.  This will be extremely useful for calibration and alignment. The data with the magnets on will contain information about muons turning as they are influenced by the magnetic field. The momentum of these muons can be calculated and compared to expectations as a nice cross-check.  The data with the magnets off will contain muons that don’t bend, and therefore draw straight lines through the ATLAS detector.  This is useful for checking the alignment between different detectors.

As of Thursday night, ATLAS is taking data with the entire detector writing out data, and will continue like this for the rest of October.  This will probably be the best data we have taken yet.  It can be studied for a few months to have us in really great shape for next year’s running with collisions.

After November 3, we won’t run much with the full detector until next year.  The detector will be opened up and people will be allowed in for maintenance, things like repairing or replacing problematic power supplies and malfunctioning pieces of electronics.

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Message from the DG

Saturday, October 4th, 2008

Yesterday, the CERN Director-General spoke to the laboratory about the present and future of the laboratory (the slides in English, and video in French, are here). He said a couple of important things.

  1. Maintenance of infrastructure previously scheduled for the winter shutdown will instead start on Monday, October 6.  This means that an effort is being made to re-start the accelerator complex in April instead of the previously scheduled June.  That is good news for getting collisions sooner rather than later in 2009.  But presumably everything depends on repairs being finished in the LHC.
  2. Concerning the LHC, a report will be issued before the inauguration on October 21 detailing what happened on September 19, and again presumably will let us know how long repairs are expected to take.
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Back to Work

Monday, September 29th, 2008

Okay, I admit it.  It took me all of last week to recover from the bad news.  I spent a lot of the week going to meetings (there were two ATLAS workshops with meetings all day every day), squeezing in some analysis of the data we did get before the accident, and the rest gossiping about the LHC status.

Even being at CERN, it was difficult to get any information on what was going on, so everyone was guessing what happened and what the damage was.  First, I heard “a magnet was damaged”, then two, 50, and 100!  Obviously, none of the people spreading rumors had any real information since none of these rumors was true.  It is strange to have to search the newspapers for an update on what is going on at your workplace.

Anyway, getting back to the emotional recovery…I felt much better after attending a meeting devoted to planning for the next 6 months on Friday.  There is clearly a huge amount of work to still do to be ready to take full advantage of the data we get next year.  While it would have been better to have some collisions this year, the real first chance for discoveries was always going to be next year, and that doesn’t change now.  We just need to be sure we do everything we can before then to be ready.  Back to work.

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The Waiting is the Hardest Part

Wednesday, September 17th, 2008

After the sprint out of the gate by the LHC and even rumors of collisions coming much sooner than expected, things have slowed down here for the last few days.  I am in the ATLAS control room on shift from 3pm-11pm, Monday-Thursday this week, and I had dreams that the LHC would collide some low energy beams during that time and I could celebrate again in the control room.  Instead it is Wednesday night, I just ate a terrible “Poulet Curry” sandwich from the cafeteria, and the LHC hasn’t had any beams at all in the last few days.

In the meantime, everyone here has been working with their piece of the detector.  The other 2 people and me who are at the liquid argon calorimeter desk have been learning a lot about the various procedures which are still new to us, updating/improving documentation, recording calibration data, and responding to small problems here and there.

Last night we recorded calibration data for most of the shift.  Then, we tried to record some cosmic muons data, but had several problems reading out our detector that stopped us.  After several hours of trying, we finally started recording data just as the shift ended.  Tonight, we have taken only about 20 minutes of data due to various problems, the last being a magnet quench.  And we are back to waiting.

The accelerator folks keep moving the time for putting some beam back into the LHC back every few hours.  It was estimated at 7pm when we got here at 3pm.  The current estimate at 10pm is no beam before 2am.  Maybe tomorrow night during my shift there will at least be one beam circulating through ATLAS.  And then hopefully only a few more days until collisions.  Just have to wait and see.

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