/ Maggie Koerth-Baker / 10 am Tue, Oct 4 2011
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  • Sunset on the Tevatron: Photos and memories from a Fermilab physicist

    Sunset on the Tevatron: Photos and memories from a Fermilab physicist

    For more than 20 years, the Tevatron reigned as the gold standard in particle accelerators. Under a berm outside Batavia, Illinois, the machine pushed protons and antiprotons to high energies around circular tracks before crashing them into each other. What's the point of that? When high-energy protons and antiprotons collide, they reproduce the conditions at the beginning of the Universe, just after the Big Bang. In the wreckage, you can find particles that don't normally exist, and observe phenomena that humans have never seen before. By rubbernecking at a particle crash, researchers hope to better understand life, the Universe, and everything. It's kind of a big deal.

    But on Friday, September 30, the Tevatron smashed its last protons.

    Ultimately, the Tevatron was simply the victim of the progress of technology. When it opened in 1983, it replaced older, lower-energy accelerators. And, in turn, the Tevatron has been replaced by the Large Hadron Collider, an accelerator capable of pushing particles to even higher energies. Once that happened, it was only a matter of time before the Tevatron felt the budgetary axe.

    The end of the Tevatron doesn't mean the end of research at the Fermi National Accelerator Laboratory, and it doesn't mean the end of particle research in the United States. But it is the end of an era.

    William S. Higgins is a radiation safety physicist at Fermilab, and a contributor to Tor.com. He helped build the Tevatron and he was on hand last Friday, recording his thoughts and some photos to share with us. Here, you'll find a sentimental scientific tour of the last day of a great piece of research equipment. Unless otherwise noted, all the captions were written by Higgins.

    Meet Bill Higgins: Wistful is a good word to describe the way I felt, as I witnessed the shutdown ceremonies, and joined the crowd at the party—think of it as a wake—afterward.

    [In the photo above, Higgins is leaning on a model of the magnets that helped the Tevatron accelerate particles.]

    Higgins: Right now I work on shielding analysis to support future operation of Fermilab's multiple accelerators. Over thirty years ago, I was assigned to work on the testing of Tevaron magnets as they came down the production line. In Fermilab's Wilson Hall, one can see a nice cutaway example. A real Tevatron magnet is a steel box 21 feet long, but here the yoke has been removed to display various layers of the cryostat: outer shell, vacuum, liquid nitrogen, more vacuum, two-phase boiling helium, liquid helium, superconducting coil, and, at the center, a two-inch vacuum pipe the [particle] beam passes through.

    On the test stands, the magnets would be cooled down, then powered for the first time. We would run the current up and deliberately "quench" them a few times, to measure how much current they could carry before making the abrupt transition from superconducting to non-superconducting state. This invariably involved the boiling of a lot of helium, the opening of a relief valve, and a loud noise something like the bellow of a bull elephant. Quenching was the most fun part of the job. The rest: a collection of precision measurements compiled into a thick three-ring binder describing a magnet's properties. Warm up, pull the magnet off, shelve the binder, and slap another new magnet on the test stand. All 1000 magnets that went into the Tevatron, plus spares, were tested this way.

    A Tevatron "gold watch":I was given a pin to commemorate the occasion [of shutting down the Tevatron]. Here it is, resting on the original design report for the Superconducting Accelerator. The cross-shaped Fermilab logo in the center is patterned after the pole tips of dipole magnets in the Main Ring, our original big synchrotron (but it also resembes four copies of a lowercase F). Surrounding it are the superconducting cables of a Tevatron dipole magnet.

    Preparing for The End: Reidar Hahn [part of Fermilab's visual media services staff] adjusts track-lighting in the Main Control Room Thursday, 29 September, after setting up TV cameras in preparation for the televised shutdown event. On right, a ridiculously large TV monitor has been brought in so that MCR participants might view the other locations. I do not know why it was needed, but "because the Main Control Room doesn't have enough display screens" cannot have been the reason.

    The Obituaries: A cart loaded with Tevatron posters ready to be handed out at the celebration.

    Behind the Scenes: Maxwell Monningh, pictured here on Thursday, was Crew Chief presiding over the Tevatron's final shift on Friday. After the officials and camera crews and Tevatron designers had left the Main Control Room for the party, the operators were busy putting the Tevatron into standby, as well as continuing to operate other accelerators.

    Machines and experiments operate 24 hours a day. In the Tevatron's early years, Max and I worked together on fixed-target operations, shepherding beams of protons as they emerged from the Tevatron, targeting them to produce secondary particles, and making sure those beams arrived at experiments. In recent years, the machine has been entirely devoted to creating collisions within its own tunnel, rather than extracting external beams.

    On Stage: Friday, 1 October, the shutdown ceremony began around 2 PM. Employees and experimenters gathered in the 800-seat Norman Ramsey Auditorium. Fermilab's Director, Pier Oddone, served as host. Others were gathered at the control rooms of the two massive collider experiments, CDF (Collider Detector at Fermilab) and D-Zero, and in the Main Control Room where the accelerator complex is operated.

    Here Dr. Oddone is dwarfed by Bob Mau, who served as head of accelerator operations from before the Tevatron started up until December 2010, when he retired. Bob explained what would happen: The CDF and D-Zero experiments would each end their final data-taking run, then the Main Control Room would terminate the "store," the counter-circulating proton and antiproton beams coursing through the vacuum pipe at the heart of the Tevatron.

    The Big Buttons: Todd Johnson, an engineer specializing in Tevatron operations, built a special panel that would look good on TV for the shutdown ceremony. The big red button—BEAM—would cause the speeding particles to end up in a metal absorber. The big green button—RAMP—would drain the current from the superconducting magnets, "ramping them down."

    A Strong Will To Live:In a somewhat fuzzy view of the auditorium projection screen, Helen Edwards, leader of the Tevatron's design team, pushes the green RAMP button, having already pressed the red button. The display at upper right shows a red trace, the beam intensity, that has dropped to zero, but a green trace indicates that current still flows through the 1000 magnets of the Tevatron.

    There was a brief surprise at this moment as the current did not cease—but after Dr. Edwards hit the green button a second time, the Tevatron obediently ramped down for the final time, to thunderous applause.

    At the Wake: At this point the party began, in tents outdoors, and in the fifteen-story atrium of Wilson Hall, Fermilab's central laboratory building. Employees were joined by hundreds of university experimenters from the user community and by retirees returning for the occasion. Flags overhead represent some of the nations whose physicists collaborate on experiments here.

    Only the Beginning: As I left the party, sunset tinted Wilson Hall pink. The Tevatron was now idle after 28 years of operation. But computers are still churning on the analysis of accumulated data from the Tevatron's experiments. Fermilab staff and users are deeply involved in experiments at the Large Hadron Collider at CERN in Switzerland. And other machines at Fermilab continue to circulate beams through underground tunnels. We'll keep right on doing physics here.

    All photos: William S. Higgins, Fermilab.

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      1. And the castle in the Girl Genius ‘Cinderella’…

    1. Posts like this are what make me love the boings. Maggie was a brilliant addition to the site. Keep up the great work!

    2. Thank you for covering this. The Kane County Chronicle barely mentioned it online.

      This shutdown makes me sad and nostalgic. I grew up 2 towns north of Fermi and remember how thrilling it was to find Fermi Lab in my Guinness World Records book after countless field trips there. We went to see the bison herd more often than the laboratory. Now I have several friends who work there. Hope they can continue there. There have already been layoffs.

      1. I worked for the Kane County Chronicle for a couple of years … even since then it’s gone dramatically downhill. They completely miss big local stories all the time.

      2. Yeah, I was going to mention the lack of coverage as well. I guess they feel like it has run its course.  I visit there often, with my kids, and wander around Wilson Hall. We’ve had many impromptu tours of the building and grounds and have yet to be surprised by what I see.  It is really too bad that the U.S. dropped the funding for a particle accelerator that would have drawfed the LHC; if it had been built….

    3. I’d like to see a description of which accelerators will continue to be operated and what types of experiments they will support.

      1. Fermilab has a number of neutrino related experiments underway. NOVA, NUMI, LBNE, MINOS, MiniBoone, and probably some more I’m forgetting about. MINOS in particular is uniquely suited towards helping with the recent “faster than light” news that went around a couple weeks ago, and will probably be helping answer that question. 

        There’s a lot of accelerator research going on too, looking for new ways to make stuff go really fast.

    4. Hopefully when you left you drove the less than a mile trip to Two Brothers Brewing and had an Atom Smasher beer in honor of the collider shutting down. 

    5. I had a great opportunity to work at Fermilab for a summer in my undergraduate physics days. I was the smallest of small cogs, but it was exciting to be part of something big.

    6. Wow does this bring back memories.

      In 1991 I led 3 busloads of science fiction fans that were attending the World Science Fiction Convention – Chicon V – to visit Fermilab.

      It was a fascinating afternoon and Bill Higgins was one of the people that helped me get the whole thing organized.

      1. I was in that group of Sci-Fi fans! Thank you, thank you, thank you. That field trip was the best part of the whole con for me.

    7. fourth pic from the bottom “Tevatron Big Buttons” shows real Tev beam signals (the green things) and most of the world’s last supply of antiprotons (lower left, bottom trace) in the Recycler. The antiprotons were lost to an offsite electrical failure two days later. A scant few e10 are cowering in the Antiproton Source, where they will be set free (into the side of a magnet) at the end of this week. (edit to reflect the pbar survivors)

    8. Kirby and TamaraRose, thanks for your kind words.  It’s been a while, hasn’t it?

      Richard Kirk, Phil Foglio is quite familiar with Fermilab, and has occasionally drawn it in his comics.  I’m trying to remember whether I’ve given a tour to Kaja Foglio.

      John Morse, there is talk– no firm announcement so far– that Fermilab may open a detector hall and a portion of the Tevatron tunnel for public tours.   Possibly,  if you are near Chicago again, you might be able to see parts of the accelerators that you couldn’t have seen while the Tevatron was running.

      Betatron, those were merely the last supply of antiprotons in the Americas.  The good people of CERN still operate an antiproton source to support experiments there, such as traps that manufacture antihydrogen atoms by the thousands.

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