• John
  • Felde
  • University of Maryland
  • USA

Latest Posts

  • USLHC
  • USLHC
  • USA

  • James
  • Doherty
  • Open University
  • United Kingdom

Latest Posts

  • Andrea
  • Signori
  • Nikhef
  • Netherlands

Latest Posts

  • CERN
  • Geneva
  • Switzerland

Latest Posts

  • Aidan
  • Randle-Conde
  • Université Libre de Bruxelles
  • Belgium

Latest Posts

  • TRIUMF
  • Vancouver, BC
  • Canada

Latest Posts

  • Laura
  • Gladstone
  • MIT
  • USA

Latest Posts

  • Steven
  • Goldfarb
  • University of Michigan

Latest Posts

  • Fermilab
  • Batavia, IL
  • USA

Latest Posts

  • Seth
  • Zenz
  • Imperial College London
  • UK

Latest Posts

  • Nhan
  • Tran
  • Fermilab
  • USA

Latest Posts

  • Alex
  • Millar
  • University of Melbourne
  • Australia

Latest Posts

  • Ken
  • Bloom
  • USLHC
  • USA

Latest Posts

Archive for June, 2008

What it looks like

Saturday, June 7th, 2008

Back at CERN! Good to be here, more students coming in, everybody getting pretty excited. Recent progress in the cavern is the installation of the beam pipe on one side. I guess this is pretty hard to imagine, so I thought a picture might help:

Here's a picture of the Beampipe going into the minus end of CMS

So, on the very bottom of the picture you see these copper looking flanges (they’re not copper, I believe they are Aluminum, but it is just a trick of the lighting). That is the very tip of the first Endcap plug. Underneath those flanges will be the Electromagnetic Endcap, we hope! (there’s been some delay, so it is now “critical path”) Extending from that is the beampipe (eventually the plug will slide over the beampipe) which then penetrates the barrel part of the detector. It might help to have a quick glance at the cartoon before trying to understand the following: from the outside radius moving inward (it is cylindrically symmetric, so this the easiest way to describe it) what you can see is

  • Muon Chambers/Magnetic Field return – the “M” in CMS stands for Muons! This the is the red layers of steel interspersed with aluminum (silver) muon chambers- there are four cylindrical layers of chambers. The red steel in between is where the magnetic field goes so that it can form a continuous loop (magnetic fields have to go in a closed loop, and they much prefer to go through steel than air). They measure muons via the ionization trail they leave behind, and we know they are muons because anything else coming from the interaction region in the center either won’t penetrate this far to the outer detectors or won’t leave a trail at all (those would be neutrinos…) More…
  • Next step in radially: Solenoidal Magnet – the “S” stands for Solenoid. This is the grey collar that looks like it has a whole bunch of metal bands going from the outside to the inside, and every few bands you can see some green cables. The bands are actually cable trays, carrying the cable connections to the inner detectors. The Solenoid itself is 13 m long and has an inner diameter of about 6 m and since it is superconducting cavities inside we can get to about 4 T, making it the most powerful magnet in the world in terms of energy stored. More…
  • (more…)

Share

Graduation Day

Saturday, June 7th, 2008

Seth's sister, Sarah, after MIT's 2008 graduationI have been in Boston this week for my sister’s graduation. Today my family and I braved rain, cold, a number of speeches, and the reading of well over a thousand graduates’ names in order to see her receive her diploma from the Massachusetts Institute of Technology.

Her degree is in physics, which just so happens to be the same as mine, but she is a very different sort of physicist than I am: the kind who actually knows how to apply her knowledge directly to practical projects. She just finished a B.A. thesis on amplitude and phase modulation of lasers for LIGO. Her next project is working with a classmate on designing a low-cost Nuclear Magnetic Resonance machine. Currently the cheapest NMR machines cost tens or hundreds of thousands of dollars, and their idea is to build a prototype machine, made from off-the-shelf components that can be purchased within a modest MIT summer grant. Then they will write up public-domain instructions, and provide public-domain software, so that others can do the same thing, with the eventual goal of making it possible for high school labs (and others with limited budgets) to study NMR.

This kind of ability, to tinker and build a working copy of something from scratch, which MIT seems to impart to its students rather effectively, always leaves me mystified and more than a little jealous. It is very different from the specialized and often-abstract work that goes into a particle physics collaboration, and part of me wishes I had the time and energy to teach myself the relevant skills. But I suppose it’s better for my sister and me to have slightly different interests at least.

Needless to say, I am very, very proud.

Share

This week, one of the faculty from Stony Brook (who I work for) came to visit. The occasion was that it was Liquid Argon Calorimeter Week, which is a sort of quarterly review of the project. While he was here, we had many good conversations about the work we are doing and the future direction of the work. It got me to thinking how useful it is to talk to someone face-to-face (I do see him over video conferencing every week). While we use many collaborative tools to work together across the ocean, there is something qualitatively different about sitting down for a conversation over coffee. And it is the main disadvantage for Americans here at CERN that we are separated from our colleagues in the US by an ocean and several time zones. There are also disadvantages for Americans that travel to CERN, like the cost and fatigue of travel.

There has been a lot of effort by the ATLAS collaboration put into allowing people anywhere in the world to be able to contribute to this experiment from abroad, and the level of success of this effort will play a big part in the overall success of this experiment. The data recorded at CERN will be sent around the world for analysis. This has been done on a small scale already, but not with the quantity of data that will be recorded when the protons start colliding. Many of us are curiously waiting to see how well this works in practice.

Many groups from the US seem to be hedging their bets on long-distance collaboration, as can be seen from the flood of people arriving now at CERN for the summer. It was probably true in the past that it was better to be on site where the data were being recorded to get the fastest access to the data, as well as to all of the experts who were at the lab. It may or may not still be the case. Many US groups are sending several people here during the summer, and some for the longer term. Hopefully in a few years when the operation of the detector is stable, more of us can physically live in the US, but still virtually be part of the ATLAS community at CERN.

Share

the power of mini-breaks

Wednesday, June 4th, 2008

Rock On 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.
(more…)

Share

This is not strictly a particle-physics topic, but it’s something that I do, and I think it is worth mentioning. The University of Nebraska is committed to making sure as many of the students of this state as possible are ready and able to attend college here. One program that we run as part of this effort is the Nebraska College Preparatory Academy, which seeks to identify students from groups with low college-attending rates (for instance, those coming from families where no one has attained a college degree) and then makes sure that those students get extra attention so that they are on track to attend UNL when they have completed high school. Currently the program works with students in Grand Island (fourth-largest city in Nebraska, about 100 miles west of Lincoln) and students from an Omaha high school can get involved starting next year. Students who complete the program are guaranteed admission and financial aid.

Yesterday and today, 24 students in the program were on campus for a “research conference.” The idea was that students would do some meaningful research during their stay, and then make a presentation on it at the end. (They also stay in the dorm, eat at the dining hall, etc.) I ended up (longish story) coordinating my department’s participation in this. Now, it is a little difficult to do meaningful research in just one day! Our solution was to have the students do one of our instructional lab experiments — a canned exercise, yes, but you can still get the idea of how to do physics, and you can actually get at some fundamental physics reasonably quickly.

This worked out pretty well — the students did good lab work and made nice posters about their experiments, and I think that they learned some of the physics concepts too. One pair of students did an experiment on radiation, where they worked with some weak beta and gamma sources and looked at how distance from the source and shielding affected the counting rates. I asked them what they learned from it, and they said that they are much more attuned to the hazards of radiation. Hmm, maybe not quite the lesson that I had in mind, especially given that the radiation dose that a person who works on a particle-physics experiment gets is usually far, far lower than what they get from background cosmic rays, but still, they seemed excited and challenged. At the end of the day, one of the guidance counselors who came along with them told me that the students really got the point that they have to learn their math if they are going to do this kind of work.

One of my colleagues, from the anthropology department, had kicked off the workshop with a talk on “What is research?” I asked her what she told them, figuring that I could use a few pointers myself. She said that her point was that “research is learning.” Probably so, although I must admit that it reminded me of a quote I heard long ago, which was that when asked “What is physics?”, one talented scientist said, “Physics is what physicists do at night.” It took me a while to really understand what that meant. 9:19 PM; I should get back to work.

Share