## Archive for July, 2008

Saturday, July 19th, 2008

Just wanted to publicly say kudos to NYT senior science editor Dennis Overbye, who has been answering the public’s science questions. He received (at least) 11 questions concerning LHC (probably many more in fact) and I think he sums up the situation rather well, so I invite you to read it yourself. I especially like his last paragraphs, but as I’ve claimed before, it is these people’s job to communicate well, so it isn’t surprising that they are quite good at it.

Friday, July 18th, 2008

The most feared/longed for date on ATLAS right now is August 11th. This is the day where we have to be out of the cavern. It is feared for people who are still completing the last of the detector installation, longed for by everyone (including those still doing installation) because it means beam is coming.

And only a few short weeks after the cavern closure, we can expect single beam (only one circulating beam with no collisions). And only a few short weeks after that, we can expect colliding beams.

So will ATLAS be ready? I find that I am asked this question more and more with each passing day. And the answer is…. Yes. Now if you ask me whether or not the calorimeters will be ready, the answer is a very definite yes! The calorimeters right now are in really good shape. Everything is installed, everything is powered, everything is being read-out.

It makes me so happy to say that.  When I started on ATLAS two years ago, Tile had problems with its power supplies. So we had essentially no supplies. And we needed 256.  We weren’t officially in the ‘panic’ state at that point, but we were certainly in the ‘very concerned’ state.

And now fast-forward less than two years. We are fully powered. With the exception of only a few Tile cells (0.4% for the exact count), all of our electronics are ready to go. Not that we don’t have things to still work on (I mean it is friday night and I am yet again still in the control room) but we are sitting pretty. And that is a really, really good feeling.

So beam-people. Is the beam ready yet?

.

.

.

.

Now?

Wednesday, July 16th, 2008

It may only be afternoon back in the States, but here in Geneva it’s pretty late for me still to be at work: 11:30 PM!  I got a late start today, though, and anyway I’ve been on a roll for the past three hours.  I managed to figure out how to do some really hard stuff, and integrate it into the code I’m writing for analyzing calibration scans of the ATLAS pixel detector.

To figure out how to do the really hard stuff — accessing some databases, if you’re interested — I made use of one of my favorite pieces of advice to give to younger graduate students: don’t be shy about asking for help!  It doesn’t come naturally to all physics students, because we’re smart and self-confident, and we like to figure things out on our own.  But ATLAS and other large experiments are social and collaborative in nature, and sometimes the details you need to do your work aren’t easy to figure out and aren’t written down anywhere.  In those cases, you can make huge progress by asking the people who do know; they can’t complain, because if they don’t want you to ask next time, then they can write the details down!

### Behind Enemy Lines

Tuesday, July 15th, 2008

OK, OK, all I meant is that I took a lightning fast tour of CMS yesterday, hosted by a RHIC colleague of mine (thanks, Dave!). But who do I run into but, not one, but two US LHC bloggers — voila:

Anyway, this was my first time seeing CMS, and impressive it was. Impossibly dense, compared to the general ATLAS impression of being impossibly huge. And this may be the last time many of us ever get a chance to see it (ironically, the better the LHC does in the first couple of years, that chance will just get smaller). So enjoy my photos (which admittedly aren’t much better/different than many others) here.

### Will work for travel money !!

Tuesday, July 15th, 2008

Hi everybody,
I was out of commission for a few weeks, mostly on vacation, mostly in Germany. And when I came back to the U.S. the price of gas had risen another 50 cents and is now hovering around $4.25 a gallon. Most of my European friends are not very sympathetic because if you use 1.5 as an exchange rate for Euro to Dollars the price per gallon in Germany is now around$9, so almost exactly double the U.S. cost. Still, that’s not the point, because small distances in the U.S. are huge distances in Europe (I can get as fast from Frankfurt to Geneva as I can from Detroit to Chicago, which is probably the shortest distance between two major cities in the U.S.). So at some point one might ask, what will be the impact on doing research abroad ? Well, travel cost will go up drastically. You’re already paying extra for drinks and luggage on some overseas flights, but the major cost hikes will come from gas prices. The transportation problem in the U.S. is becoming so bad that people already are contemplating the effect on the higher education system. The New York Times featured an article on July 11th that shows that students more and more sign up for online classes, and many of them state the cost of driving to and from school as one of the major motivators. On-Campus education could, at some point, become prohibitively expensive, not because of college tuition but because of additional transportation cost. So the question might arise whether in a time of world-wide science globalization, on-site science might become prohibitively expensive and everything besides maintenance needs to be, and will be, done remotely via GRIDs, EVO, etc..
Still, the on-site shift load that I reported on last month seemed daunting and that is just the minimum commitment to keep the experiments afloat. So both the U.S. groups as well as the U.S. funding agencies need to seriously consider the effect an economy in crisis, and therefore a potentially staggering increase in transportation cost to and from the experiments, might have on our future plans.

### Why is computing interesting?

Friday, July 11th, 2008

Given the tedium of what I need to deal with day to day on the computing, what is it that makes computing interesting?  Let me make a comparison with what is going on in the collision halls.  My colleagues underground at CERN are working very hard as we head towards LHC startup.  There are some very tight time constraints at this point, and they are working with very complex systems that are pushing the limits of their technologies.  And as we head into these final weeks, the separate systems that have been under development for years must be integrated into one large experiment.  It’s a tremendous task, and I don’t want to take anything away from what they are doing.

However, they are starting to get out of the woods.  The door to the collision hall will be shut at some point, and very little can be changed after that.  And the number of people who will interact directly with those systems is relatively small; a team of experts, who will continue to make a lot of effort to make their hardware work and keep it running happily.  Most of their work will be hidden to the world; physicists will be happy to see lots of silicon hits on tracks, but they will only have a vague idea of how much labor went into that.  (I’ll say again, the hardware guys are under-appreciated!)

In contrast, just about everyone on CMS will interact with the computing in some way, which means that my problems are just beginning.  Everyone will want to know where the datasets are.  Everyone will be trying to submit jobs.  Everyone will be trying to make plots.  Performance will be documented and updated regularly on Web pages.  This means that everyone will have an opinion on what works well and what doesn’t, and they won’t hesitate to voice it.  And all the computers are above ground, and software can be modified with a few keystrokes; we can tweak things endlessly, and we might well be called upon to do so.

So in fact this is a very human enterprise — we are building a system that 2000 motivated, smart and creative people will be using every day.  We need to make it work for each of them as individuals, while also making sure that the group as a whole is not harmed.  And while ultimately we have to build good systems, there is a lot of psychology and sociology involved too.  Everyone needs to actually buy in to the idea of distributed computing for it to work, which might be hard while we still work through all the kinks, and everyone will need to trust that they are being treated fairly.  One of my mentors said to me once, “If all of our problems were physics problems, this job would be easy.”  She was of course referring to the fact that we must work with people every step of the way.  Physics equations and plots are interesting, but the human aspect of the work adds an extra dimension.

It is on my mind today because I have been corresponding with some users who are having trouble running jobs on our site.  It sounds like there could be any number of things going on…many of which may have nothing to do with the performance of the cluster here.  But it doesn’t matter; I’m invested in getting the entire chain working, because we have to build confidence.  More to come, I’m sure.

### ATLAS vs. ATLAS

Thursday, July 10th, 2008

While CMS folks are off scuba diving in Cyprus, ATLAS is entertaining itself in a somewhat more strenuous way back here in Bern — playing an intramural soccer game in the Stade de Suisse: The ATLAS Lions vs. the ATLAS Warriors. OK, most of us are goofing off watching, and rattling yellow noisemakers every time something happens to either team (I mean we’re all collaborators in the end), but we certainly wouldn’t all fit on the field. I’ll let you know the score, when it’s over (too tired to liveblog, given that I gave a talk today).

UPDATE: Lions 5, Warrors 3 — ATLAS wins! Um.

### Getting the news

Thursday, July 10th, 2008

Recently one of my posts received the following comment and I thought it merited a more thorough explanation.

I heard a magnet broke. When will it be fixed? Why is this information not easier for the public to access – am I just an idiot? – Tony

First about the magnet tests. There are four major ‘parts’ to ATLAS magnet system; the solenoid magnet, the barrel toroid magnet and two end-cap toroid magnets. In the past few weeks, extensive tests on all of these systems have been ongoing. During the tests, a leak in one of the end-cap toriod Helium cooling pipes was discovered. As a result the tests on this magnet stopped so that the leak could be fixed. But the repair is already completed and there was not a large impact on ATLAS’ schedule.

But in regards to the second question, ‘No Tony, you are not an idiot!’ Even within ATLAS, it is very difficult to get the latest news. To keep up-to-date on recent ATLAS activities, I highly recommend the ATLAS e-news. The ATLAS e-news is a weekly publication highlighting the latest issues within ATLAS. It is aimed for ATLAS collaborators. But as the e-news is written by three professional science writers, the technical jargon is kept to a minimum. There is also a version of the e-news aimed for the general public but this is not updated as frequently.

So check out the ATLAS e-news. It has not only all the interesting news but also profiles of people on ATLAS as well as cool pictures.

### CMS in Cyprus

Wednesday, July 9th, 2008

Hah!

If I’m quick I’ll get this in just after Peter’s blog. While ATLAS went to Berne, CMS went to Limmasol (Lemesos) Cyprus for the collaboration meeting. Now, it is rather a critical time, so the wisdom of going fairly far away is dubious, but getting the upper management and riffraff out of the hair of those really doing the work for a while is maybe not such a terrible idea. I’m told it was quiet and people could get work done at CERN. Anyway, I had a good time-Limmasol is a resort town, so it wasn’t particularly serene (think Miami Beach for Brits and rich Russians) but I did get into the countryside a little which was quite nice. Also, my buddy Chris proposed an alternative excursion to the one planned for the whole collaboration, which was very fun, since I only get to do this particular activity once every blue moon. He’s on the right, I’m on the left

In other news, we have tracks in our tracker! Triggered by Cosmics via the muon chambers, with more than 95% of it turned on! So far performance looks really excellent, I’ll provide more details soon

### ATLAS in Bern

Wednesday, July 9th, 2008

Believe it or not, this is a photo just outside the ATLAS meeting in Bern, Switzerland that Monica and I are both attending this week. We’d never met before, but I found myself sitting behind her, so introduced myself by pointing out that ATLAS has put us both on their “Blogs” outreach page. Gee, I have to get posting more.

But about that soccer field, the meeting itself is being held at the Stade de Suisse, just outside downtown Bern. The UEFA EURO2008 tournament just ended of course (which I believe inspired the locale), and just in time for an ATLAS-on-ATLAS soccer match tomorrow. Stay tuned for photos posted to my Flickr set. You can also see some photos in and around Bern, which is a lovely place. And some nice mountains nearby, that my wife and I hiked in and on and over last week.