Boom! March 30, 2010
Posted by gordonwatts in CERN, LHC.3 comments
Do not start with a whimper… Start with a…
![atlas2010-vp1-152166-639756[1]](http://gordonwatts.files.wordpress.com/2010/03/atlas2010vp11521666397561.png "atlas2010-vp1-152166-639756[1]")
or perhaps you’d prefer a…
![atlas2010-vp1-152166-399473[1]](http://gordonwatts.files.wordpress.com/2010/03/atlas2010vp11521663994731.png "atlas2010-vp1-152166-399473[1]")
That first event – the small red track (click to enlarge) is actually a muon candidate. Something we almost could never see with 900 GeV collisions from last December – very little was powerful enough to make it out that far.
So, now the real work begins. Soon the press will pack up and we can get down to actually making sense of this fantastic new microscope we’ve been given! It is going to be a fun 18 months of first data!
For more event pictures, from all the experiments, not just ATLAS, see the main CERN web page.
Collisions March 30, 2010
Posted by gordonwatts in CERN, LHC.3 comments
Wow. It is almost 5 am. I have a meeting in 3 hours. It is a bit anti-climatic watching it alone in the dark here in Seattle. But still. This is the beginning. The next year will have many more sleepless nights. A job well done by everyone who has worked for so long to see these first collisions – many for 20 years or more!
What do you mean it isn’t about the $$? December 16, 2009
Posted by gordonwatts in ATLAS, CERN, LHC, life.3 comments
A cute article in Vanity Fair:
Among the defining attributes of now are ever tinier gadgets, ever shorter attention spans, and the privileging of marketplace values above all. Life is manically parceled into financial quarters, three-minute YouTube videos, 140-character tweets. In my pocket is a phone/computer/camera/video recorder/TV/stereo system half the size of a pack of Marlboros. And what about pursuing knowledge purely for its own sake, without any real thought of, um, monetizing it? Cute.
Something I found out from this article – The LHC is the largest machine ever built. Ok. Wow. Ever!? I would have though that something like a large air craft carrier would have beat this. Still.
The attention span is another interesting aspect I’d not thought about. You know that the first space shuttles were using magnetic core memory (see the reference in that Wikipedia particle). There were a number of reasons for this – one of them was certainly there was no better technology available when they started. Before it was built more robust memory appeared – but it was too late to redesign. Later space shuttles were fitted with more modern versions of the memory.
In internet time, 6 months or a year and you are already a version behind. And it matters. It would seem part of the point of the now is to be using the latest and greatest. You know how everyone stands around a water cooler discussing the latest episode of some TV show (i.e. Lost when it first started). Now it is the latest iPhone update or some other cool new gadget. Ops. Hee hee. I said water cooler. How quaint. Obviously, I meant facebook.
Projects like the space shuttle or the LHC take years and years. And a lot of people have to remain focused for that long. And governments who provide the funding. You know how hard that is – especially for a place like the USA where every year they discuss the budget? It is hard. Some people have been working on this for 20 years. 20 years! And now data is finally arriving. Think about that: designs set down 20 years ago have finally been built and installed and integrated and tested.
This science does not operate on internet time. But we are now deep in the age of internet time. How will the next big project fair? Will we as a society have the commitment to get it done?
I like the writing style in this VF article – a cultural look at the LHC. They do a good job of describing the quench as well. I recommend the read. And, finally, yes, this post ended up very different from the way it started. 
Thanks to Chris @ UW for bringing this article to my attention.
First LHC Collisions at ATLAS November 23, 2009
Posted by gordonwatts in ATLAS, LHC.3 comments
If you follow newspapers, facebook, or twitter, you’ve undoubtedly seen these already – but the LHC has done it – managed to collide two beams of protons! They never made it that far last year. Here is an event from ATLAS:
![atlas2009-collision-vp1-140541-171897-new[1]](http://gordonwatts.files.wordpress.com/2009/11/atlas2009collisionvp1140541171897new1.png "atlas2009-collision-vp1-140541-171897-new[1]")
That isn’t to say there is a lot of work left to do. These are at an energy 900 GeV, which is much less than the 7,000 GeV energy they plan to get up to by the end of running in 2010. And the beams are not very intense yet. Still!!!
I’m currently in Seattle – I wish I could have been there for this. Being in or around the control room – though I would have been mostly in the way for this phase. Unlike at the Tevatron, I wasn’t really responsible for any bit of the detector or DAQ at ATLAS – and those are the people that need to be there right now. Still, I would have loved to have been there.
Ironically, I first heard about these collisions from facebook. People in the control room that I’m friends with were posting status updates as LHC tuned up their beam. Press release, twitter, etc., all lagged behind that. And of the people I’m friends with a theorist posted the news second (!) – this theorist was not the member of any collaboration. Ahhh… new media! 
So, taking that sentiment to the limit. I must now ignore the LHC and get back to preparing for class! Must. Not. Look. At. Accelerator. Status. <said in best Cptn’ Kirk voice>.
Fizzle! August 4, 2009
Posted by gordonwatts in ATLAS, Fermilab, LHC, Tenure, university.5 comments
The biggest, most expensive physics machine in the world is riddled with thousands of bad electrical connections.
Ouch.
So starts a mostly accurate article in the New York Times about the current state of the LHC. There is good news and bad news in this sentence. To paraphrase a famous politician currently sight-seeing north of South Korea, it really depends on your definition of the word bad. To most people, if someone says that the electrical connection between your light and the wall socket is bad, then that means your light won’t work. That is the normal definition of bad. We High Energy Physicists have a different definition of bad.
For us, bad means that the connection isn’t going to conduct as much current as it could (I had a blog post about this a while back – but this article contains an excellent explanation – well worth registering if you have to to read it). And this is the reason behind the timing of this article. As I mentioned in that article it would not be until the beginning of August that the LHC group of scientists would have finished measuring all those connections – all those splices – and know exactly how bad they were. Tomorrow the LHC and CERN will announce exactly what energy they will run the LHC at initially.
But scientists say it could be years, if ever, before the collider runs at full strength, stretching out the time it should take to achieve the collider’s main goals…
And that is the bad part of the news. The bad connections mean that we can’t run at the full 14 TeV energy – we will run something short of that (I’m betting it will be 7.5 TeV – if I get it right it isn’t because I have inside information from the accelerator group!). The article is correct that running at this reduced energy won’t give us the access to the science we’d all expected and hoped for if we were running at 14 TeV.
But another thing to keep in mind is: we need data. Any data. And not to discover something new – because we need to tune up and commission our detectors! We’ve never run these things in anything but a simulated collider environment or looking for cosmic rays. We would probably be able to keep ourselves busy for almost a year with two months of data.
Peter Limon, a physicist from Fermilab got it right:
“These are baby problems,” said Peter Limon, a physicist at the Fermi National Accelerator Laboratory in Batavia, Ill., who helped build the collider.
Indeed, these are birthing problems – no one has ever run a machine like this before. Which brings me to the one spot in the article that got my hackles up:
“I’ve waited 15 years,” said Nima Arkani-Hamed, a leading particle theorist at the Institute for Advanced Study in Princeton. “I want it to get up running. We can’t tolerate another disaster. It has to run smoothly from now.”
Nima, whom I also know (and like), is a theorist. If an experimentalist said this we would all make them run outside turn around three times, and spit to the north to cancel the jinx they would have just placed on the machine. I think we can all guarantee that there are going to be other failures and problems that occur. We hope none of them are as bad as this last one. But if they are, we will do exactly what we’ve done up to now: pick up the bits, study them, figure out exactly what we did wrong, and then fix it better than it was originally made, and try again.
There was one last quote in that article I would have liked to have seen more of a back story to:
Some physicists are deserting the European project, at least temporarily, to work at a smaller, rival machine across the ocean.
The story behind this is fascinating because it is where science meets humanity. The machine across the ocean is the Tevatron at Fermilab (I’m on one of the experiments there, DZERO). There is plenty of science still there, and the race for the Higgs is very much alive – more so with each delay in the LHC. So scientifically it is attractive. But, there is also the fact that a graduate student in the USA must use real data in their thesis. Thus the delays in the LHC mean that it will take longer and longer for the graduate students to graduate. In the ATLAS LHC experiment the canonical number of graduate students quoted I hear is about 800. Think of that – 800 Ph.D.’s all getting ready to graduate – about 1/3rd or more of them waiting for the first data (talk about a “big bang”). Unfortunately, you can’t be a graduate student forever – so at some point the LHC is taking long enough and you have to move back to the USA in order to get a timely thesis. Similar pressures exist for post-docs and professors trying to get tenure.
UPDATE: Just announced earlier today: they will start with 3.5×3.5 – that is, 7 TeV center of mass. This is exactly half the design energy of the LHC. The hope is that if all runs well at that energy they can slowly ramp up to 4×5 or 8 TeV. At 8 things start to get interesting as a decent amount of data at 8 will provide access to things that the Fermilab Tevatron can’t. Fingers crossed all goes well!
Energy vs Power vs Heat vs Oh no! July 5, 2009
Posted by gordonwatts in CERN, LHC.2 comments
Last post I mentioned the LHC update that was given at a recent meeting at CERN. One cool thing Steve Myers’ showed during his talk was a discussion of the quality of the splices and how it might affect the LHC’s ability to run.
For a sample of the trade-off, check out this plot, stolen from page 46 in the talk.
![image_thumb[1]](/Users/gwatts/AppData/Local/Temp/WindowsLiveWriter1286139640/supfiles2562B54E/image[3].png "image_thumb[1]")
Along the x axis is the measured resistance between two magnets (across the splice). The units there are nano-ohms – something only the most expensive multimeters can measure. If you remember your Physics 101 course, you remember P=I^2R (power is current squared times resistance). The units of P are Watts (!) – just like your light bulb. These are superconducting magnets, of course. The magnets are very powerful and so have 1000’s of amps of current flowing through them. So even small R’s mean decent heat sources. Heat warms up the magnets, and makes them no longer superconducting – and that can be a disaster (a few of these is not a problem – it happens every now and then – but a chain reaction is what caused the last September accident). So – the splices, which aren’t superconducting, need to be excellent and have almost no resistance. Like 10-15 nano-Ohms.
The Y axis is how much current you are pumping through the magnet. Current is proportional to the magnetic field, which is proportional to the energy we can run the LHC at. As you can see, if you can run at about 6700 amps you can run at 4 TeV. If you run at 8300 amps then you can run at 5 TeV.
The red and green lines are the keys to reading this plot – they are two different conditions for the state of the copper joints. The LHC machine folks always talk about the worst case scenario (the red line) – but I’m not 100% what the difference between the two is. Lets say you want to run at 5 TeV. Follow the 5 TeV line over from the left of the plot until it hits the red line. You see that it drops down to 58 nOhms. That means all splices have to be less than 58 nOhms in order to run at this energy. The machine is full of these splices. So this is a bunch of work checking these guys!! [listen to the video on the agenda page at about 30 minutes in]. So, one of the things the LHC engineers are doing is measuring all the splice resistances and then putting them up on that plot to see where they are.
BTW, nominal is 10-12 nOhms, and they need to be less than 25 to run at a full 7 TeV (two beams at 7 TeV gives you 14 TeV, the design of the LHC).
LHC News July 3, 2009
Posted by gordonwatts in CERN, LHC.2 comments
Sorry if this is old news…
CERN management recently had a council meeting. These meetings take place between the council and the CERN directory general. Big funding changes, new projects, major schedule changes, a new country wants to join CERN, etc., all have to be approved by this council. As you might imagine the recent council meetings have been dominated by the “schedule changes” (I don’t actually know as a function of time if that is true, but I would imagine).
What is nice about the current CERN DG is that he usually immediately sends a message out to the public and the the CERN folks. Much better than reading about an updated CERN LHC schedule in the Geneva newspaper. Even better, a presentation to all of CERN (and an open webcast) is schedule. The last one just happened (there is a video link and slides link at the top of the agenda, just under the main agenda title).
Everyone is eager for data. I’ve discussed what I think are some of the pressures on the accelerator division previously. This meeting is a continuing part of that conversation.
It is clear they are doing a huge amount of work. They have a lot done. A huge amount. From a physicist’s point of view, the most frustrating thing about Steve Myers’ talk was there is no date and no energy. It wasn’t clear to me what the plan was until someone asked a question at the very end of the talk. Basically – they will have measured the splices (electrical connections) in all of the LHC in early August. Those splices are what caused the disaster last September – so it is important that all of them be carefully measured. And once they have measured everything – then they can start a discussion with the experiments on start up schedule and energy.
Next time something on the trade offs…
Da Vinci’s Take on the LHC February 9, 2009
Posted by gordonwatts in LHC, physics life.3 comments
This is old news, but I stumbled across this for the first time. Check out this drawing:
![PWnew2_11-08[1]](http://gordonwatts.files.wordpress.com/2009/02/pwnew2-11081.jpg "PWnew2_11-08[1]")
That is the CMS detector, taken apart. Stunning, huh?
Obviously, Da Vinci didn’t draw that – rather a member of the CMS collaboration, Sergio Cittolin, did. He is the project leader for the trigger and data acquisition systems for CMS. Apparently they are on the cover of the CMS physics Technical Design Reports (TDRs). Sadly, as I have only the electronic version, I never caught this! The drawings are beautiful. I want some large poster size ones to hang up outside my office at UW!
I found this in a Physics World article.
Chamonix: What The LHC Experiments Will Be Doing This Summer February 3, 2009
Posted by gordonwatts in LHC.3 comments
![LHC_magnet[1]](http://gordonwatts.files.wordpress.com/2009/02/lhc-magnet1.jpg "LHC_magnet[1]")
Wow – I didn’t realize how many meetings there were going on this week! In ATLAS there is the trigger workshop I’m attending in Beatenberg. I know of a Liquid Argon Calorimeter week going on in Marrakesh (lucky bastards!). The Chamonix meeting, however, is the one where everyone wishes they could be a fly on the wall at.
Every year for years and years (going back more than 20 years, I’m given to understand) the CERN accelerator folks decamp to Chamonix to discuss all things CERN accelerators (perhaps to do a bit of skiing to!?!?). CERN is large and quite active – with more than the LHC going on, so they have a lot to discuss! Of special interest, of course, is how they will manage the startup for the LHC.
The current date for startup is this summer — July. That is subject to change, of course, if they find a problem with the ongoing repairs. The news I’ve heard of the repairs has been quite smooth – though I’m not really plugged into the rumor mill. So perhaps that July date will stand – which would be great.
But there is a lot more to decide than the start up date. What energies will they try to run at? How many protons will they put in the machine: how intense will they make the beam? How fast will they ramp the energy and intensity up? Heck, how long will they experiment with single beams before they try colliding beams?
From the experiments point of view, the most important a few collisions (at least in my opinion). It almost doesn’t matter what energy they are at. Even just a few days would be a huge help to commission the detectors. We’ve taken 100’s of millions of cosmic rays now – we know a lot about the basic performance of a substantial fraction of the detector. But the trigger and timing ourselves to match the LHC’s collisions is hard! We all guess there is a lot of work there. And any data at all would be a huge help. The process is sort of like diminishing returns: the first dollop of data lets you get the big things right, the next the next most important things are tuned up, etc. And what is worse is those first fixes are usually the largest and require the most time – imagine if we’d had a few days of collisions last September. Wow – we’d be so much further along than we are today (or we know that we were so much further along if everything had worked)!
Of course everyone wants to do physics as well. There the experiments will probably push for higher energies – if the LHC will accumulate only a small amount of data those higher energies are required to give any competition at all to the Tevatron. Of course, the LHC may want to operate at lower energies to keep things safe.
We’ll see what they say…
2009. Ready or not January 2, 2009
Posted by gordonwatts in ATLAS, CERN, D0, Fermilab, LHC, politics, science.4 comments
We’ve made it through the first day of 2009. I have mixed feelings about this coming year.
- Federal Science Funding Levels. The economy is crashing down around our ears. Business responds quickly (layoffs
) – government is a bit slower. If things followed their natural course of action that would mean science funding, along with everything else, will take yet another hit. However, the incoming Obama administration seems to be committed to spending the USA’s way out of this recession, so in the end funding might not change very much. I am hopeful that hard sciences funding will remain at least stable. - Federal Science Funding Directions. Climate change is what the Obama administration is focused on. There is a good chance that if you are researching something connected with climate change you may have access to increased funding opportunities. I would expect a funding profile similar to NIH’s funding during its years of increase. I would like to think that funding will spill over into the physical sciences – it should because there are connections between the physical sciences and clean air technologies. All of this is applied scientific research. I hope that the pure research funding gets an increase as well, as an investment in this countries future (particle physics is pure research, of course). I’m feeling neutral here.
- Federal Science. Obama’s science team is just a BLAST of fresh air when compared to the current administration’s. After all, his DOE nominee is a Nobel prize winning experimental physicist. Even if the science advisor isn’t elevated to a cabinet position (PDF), there will be someone in the room that knows a great deal about science, research, and how it is done. Even if there are cuts to science funding, I’m very hopeful there will be intelligent cuts rather that unscientifically motivated cuts. I’m very hopeful in this respect.
- State Universities. The economy in states is depressing. Some states, like my own (Washington) that rely on sales tax are being hit hard and very fast. State universities can’t escape that, obviously, and my university is no exception. Unfortunately, this usually translates to reduced raises, inability to counter offers from outside, reduced support for research, etc. In our own department I wouldn’t be surprised if some people left for other universities that, for whatever reason, were able to make good offers in this awful climate. There is, in fact, already evidence this is happening. The only consolation is most universities are in the same boat, and so most of them are having similar problems. I know less about private universities, but I do know the endowments of many of them are also having difficulty. I’m very downbeat about this: it will be a rough two years at least, I think.
- My Science. When it comes to the Tevatron and the LHC… Well, I see no reason that the Tevatron shouldn’t continue to break records in luminosity (they just broke one earlier this week). And the experiments will continue to be flooded with data. While it is possible for one experiment or the other to have a catastrophic failure, I doubt that will happen. And they should continue to produce papers and science at a furious rate. I also am looking forward to real LHC collision data this year. While I hope it will be at the full 14 TeV, I suspect it is more likely to be at 2 TeV, just a hair above the Tevatron’s luminosity. We’ll hopefully know what the machine scientists think about that sometime in February. I’m really hopeful about this.
- New Years Resolutions. Well, I made only one. That way I have a hope of keeping it: make bread more often. I think there is a chance that I will keep this one. Especially now that I’ve said it publically.
Of course, this should also be a fun year, as noted by the Beacon News:
Frustrated with their failed attempt to destroy the world in 2008, the scientists at Fermilab and their counterparts at Switzerland’s CERN physics lab resolve to perfect their new device, the Large Planet-Sucking Black-Hole-o-Tron.
Here is to another great year of data collection and science at the Tevatron and first collision data at the LHC!
