## Archive for April, 2008

### Earth Day and Doomsday

Saturday, April 26th, 2008

Hi Folks-

In honor of Earth Day (and because I still retain my Badger Pride, in this case for Earth Day founder Gaylord Nelson) I ask you a question: which is more likely, that we will all be swallowed up at the turn on of the LHC, or that we will adiabatically ruin our planet to satiate our increased demands for convenience and “higher quality of life”. The Energy problem/Global Warming/choose your own name for it is getting more and more attention these days, for good reason, and so it has been on my mind. At MIT, we have an Energy Initiative where the Institute as a whole has taken up the energy challenge, and people like Governor Patrick are giving talks to highlight its importance. In the Physics Department, we focus more on technological solutions, but I am not convinced this is the way to go. My brother, who has been working for Wisconsin Energy Conservation Corporation for the last 10 years or so (it has been at this business for 25 years!) tells me that in we currently have the technology to dramatically reduce our energy consumption (working with energy providers, building developers, and ordinary consumers) which is more expensive up front, but in the end saves money as well as energy. It is just a matter of getting people to change their habits-but that is really hard.
My main example of this is during my daily commute. My vehicle of choice is:

which I ride for 10 minutes mostly along a path to a subway (it’s called the “T” in Boston) which takes me to MIT. I ride all year long (thanks to my town of Arlington, which has decided to plow the bike path) except in really bad weather when I take a bus to the T. This has many advantages:

• With gas at $3.70/gallon and parking at$500/semester it’s better economically (My T pass costs $37/month, subsidized by MIT). By the way, in Switzerland gas was something like$5.20/gal last year, so it is still cheap in the US. Parenthetically, I am continually chagrined by our current leader’s commitment to reduce US dependence on foreign oil – not oil in general, that would be detrimental to the US oil industry, with which the current administration shares some pretty cozy past history, no? OK, I’ll step off the soap box.
• I get at least 20 minutes of exercise a day, whether I like it or not. I don’t have to set aside extra time for exercise, it is part of my daily routine, and 20 minutes a day, done regularly, goes a long way. And it is outside, fresh air, not cooped up in some health club (which again costs more money)
• It is faster! Well, if there were no traffic, it might be slightly faster by car, but when in Boston is there no traffic? Actually the fastest way to get from my house to MIT is bike all the way, but the bike back in traffic is no fun (too many cars, too much pollution, too many drivers venting their stress with their driving tactics and their horn) so I usually take the T instead.
• There is a certain satisfaction I get out of cruising through traffic like a hot knife through butter while everyone is stuck in gridlock.

I’ve been using my bike for commuting since college, except for a few stints here and there when I had to deal with the kids at the same time, and I have to say the driver’s attitudes are getting better. Whereas there was little respect for bikers back in the day, now for instance I cross one road on the path every morning (Lake St) and I’d say 90% of the time cars go out of their way to yield the right of way to me- kudos to Arlington!

Often I have ample opportunity to observe the car traffic flowing around me, so I play a little game. I try to see how high I can count consecutive cars with single occupants, until I see one with more than one occupant, upon which I reset the count to zero. I think the highest I’ve ever counted was around thirty, and it isn’t hard to get to 10 at all. Forget the bike, what if half of those ten people in their car all alone got into someone else’s car – what effect would that have on traffic accidents, length of commute, pollution, parking space, noise, energy consumption…at the cost of being able to come and go as one pleases (but not really, because they schedule around traffic, no?). So I think the real challenge is not necessarily getting the technology but changing the mind set – the arguments are convincing, if you can get people to listen. I have a dream about getting school kids walking to school or waiting for the bus to play this game, and report their maximum count, then chart it as a function of location and time to see which part of the US is the most carpool friendly, but that’s not my day job. Anyway, awareness is what Earth Day is all about, so thanks Governor Nelson

PS I know this isn’t about the LHC so much, but we physicists tend to think about all sorts of stuff…and for readers near Boston, get on your bike duringBay State Bike Week

### Beam Schedule

Wednesday, April 23rd, 2008

The beam schedule. It is a constant source of anxiety at CERN. If you are interested in the latest-minute fluctuation in the beam schedule, I am not the person to ask. As a principle I refuse to worry about it because there is absolutely nothing that I can do to change it. The beam schedule will be what the beam schedule is regardless of whether I worry or not.

Instead I prefer to lose sleep over preparing ATLAS for beam readiness. Because it would be quite embarrassing with all the hype about the beam schedule to then not have a working detector. And preparing ATLAS for beam is something that at least I can contribute directly to.

The other reason I don’t try to determine the beam schedule on a daily basis is because then I would have to interpret charts like this.

But there are some major announcements worth noting. First the current schedule plans that the machine will be cold (to superconducting temperatures) by mid-June. And that we could expect single beam in July. The first physics run in 2008 will be at an energy of 10TeV. (The machine design is 14TeV and for comparison the Tevatron accelerator in Chicago is 1.96 TeV).

There is disappointment from some that the first run will not be at the full design power. But for me, any beam will do. We have been building and testing this detector for so long. We all want to take it for a test drive. Even a ‘little’ 10 TeV one.

### Racing Again

Tuesday, April 15th, 2008

To escape the continual control room chaos, I decided that a little mini-break to back to California was in order. I always go back at this time because the first weekend of April is San Diego Crew Classic, one of the biggest crew races on the west coast. And every year my old rowing teammates from college get together and race. Usually people’s response to this is, ‘You are going to fly 15 hours back to California for eight minutes of racing?’ And the answer is Yes! Absolutely. Without hesitation. I love racing but racing with old friends who I once spent four years training with is priceless.

In college, Crew Classic was a very important race for determining standing and rankings. But now, as alumni, we’re all about just finishing respectably. And finishing respectably means not being so far behind that we are beaten by the official’s motor boat which follows slowly behind the race. These days we take our mantra from a Toby Keith’s song which proclaims, ‘I ain’t as good as I once was but I’m as good once as I ever was’. In other words, we might be good for eight minutes but don’t ask us to race for nine.

But despite the low standard of ‘just finishing respectably’ that we set for ourselves, we managed to do very well. We took 5th place out 15 teams (9 of which were collegiate teams). Including beating our own UCI JV team (which the JV team understandably was not very happy about. Sorry guys). The fact that we can beat any college team is really amazing. Now if, heaven forbid, we were to actually train before the race (compared to showing up completely jet-lagged from a 15 hour flight for example), imagine how well we could do. We promise that every year though: ‘For next year’s Crew Classic, we will train!’. Never happens.

### More press!

Thursday, April 10th, 2008

Well, the Hawaii botanist brouhaha isn’t particularly great, but it did raise the public’s awareness of the LHC, even on radio quiz shows where their non-expert opinion of the nature of the universe just after the Big Bang was “there were no good restaurants”. Probably have to agree with that, although I just got done reading “The Restaurant at the End of the Universe” by Douglas Adams to my kids, so if I couple that with Time Reversal invariance, maybe I can come up with a theory of good restaurants at the beginning of the universe too? All facetiousness aside, I guess (almost) all publicity is good, but we’ll probably do better when Angels and Demons hits the big screen.

### CERN Open Day

Sunday, April 6th, 2008

Fun, it’s CERN open day today – wish I could be there.  Open days at RHIC are a blast — especially when you can finally see experiments which you don’t work on — and the buzz at CERN is certainly getting louder and louder.  Anyone see anything new and great?

### Delicate Timing

Tuesday, April 1st, 2008

I have been remiss. I haven’t written anything since the beginning of March. Can I blame my husband and my apartment? He’s been working really hard so I have been picking up some of the slack at home…and we’ve been painting our little apartment. I am certain that in the 10 years its been in existence, it hasn’t been painted even once, so it is very necessary. Our walls are heavily textured and suck up the expensive and thick acrylic paint like a sponge. It was hard work, but it looks way better!

CERN recently had Good Friday and Easter Monday as lab holidays, so the whole lab quieted down for a four day break. Just before it started, I decided to do a study of the relationship of two clocks used by my system.

In order to capture the data coming on our links from the calorimeters we have one clock at a specific frequency. It has one tick every 8.33 ns (0.00000000833 s), or 1/3 of the LHC machine’s tick of once per 25 ns (every LHC tick is a possible collision). We do this to speed up the rate at which our data is processed on our boards.

Our second clock has one tick every 6.25 ns or every 1/4 of a LHC machine tick. We have a specially designed high-speed chip, called the Phase ASIC (Application Specific Integrated Circuit) which takes the data coming from the links every 8.33 ns and rearranges it to run at the 6.25 ns clock. This way we can process lots of data quickly, in parallel. However, the clocks’ phase has to be good, that is the relative ticks have to be aligned in a certain way. This is pretty delicate and requires careful study.

I spend two evenings, until 10pm, clicking buttons on display to make a study of this relationship. I can’t say it was exciting. It was necessary to take frequent breaks to avoid clicking too soon or missing one…about like watching my paint dry. But at the end I had a nifty plot, which gave me a great idea of where I should set those clocks.

This has to be repeated, but the next time I will automate! I didn’t have the tools then, but I do now, thank goodness. It can even run without me.

### The Control Room Life

Tuesday, April 1st, 2008

If you were to analyze my daily life based on my posts, you would probably conclude that my average day consists of sitting around in the control room, sitting around in meetings, taking cosmic data, being interrupted by power cuts and cabling things. And today I am certainly 4 for 5 in that list. I spent most of the week in the control room, squeezed in a few meeting, took some cosmic data and was stopped by a full power cut thus ending all attempts at data taking. I have yet to cable anything, but the day is still young.

We are in yet another ‘combined running’ week which is a lot like one of the milestone weeks. But unlike the Milestone weeks which combined all sub-systems in ATLAS, in this week we are only combining the calorimeters: TileCal, Liquid Argon, and the level-one calorimeter trigger. Pretty much from now until beam, we will be having combined running weeks. For example Calo-week this week, or Muon-week, or Inner Detector week or Muon-Calo week, etc.

What we get with the combined running weeks is priceless: the chance to see the sub-systems all running together and to be part of the intensity in the control room as everyone works to get ATLAS ready for beam. But it is not without frustration. When you build any detector, especially something this big, patience is a necessity. Take this week for example, we want to run some tests of our timing but we are delayed several hours because of DAQ problems. Finally we start the tests and the control goes dark due to the power cut. This is life when commissioning a detector. It is a 3-to-1 ratio. What you think will take one hour, always ends up taking three. And it is incredibly frustrating but there is nothing you can do but wait.

That is the control room life. Long periods of nothing, followed by intense periods of frantic activity. Ah! The power is back. The waiting is over, its time to go again!