Designing the Next Big Machine

By JoAnne Hewett | February 8, 2007 10:01 pm

The Large Hadron Collider has yet to begin operations and the particle physics community is already looking ahead to the next big machine: the International Linear Collider. The ILC would collide electrons and positrons at energies of 500 GeV. Accelerator projects have a long lead time, and if we want to follow up on the questions that the LHC data will invariably raise, we have to get started now. Broad international support was shown for the ILC in 2003 when a significant fraction of the worldwide particle physics community signed a consensus document, which served as a blueprint for the physics case of the machine. Today in Beijing, the Reference Design Report (10 MB), which is a detailed technical blueprint for the design of the accelerator, was released. It is the first fully integrated design for the ILC and it contains the first full cost estimate.

It’s been a long road to get to this step. The physics case is really rather simple. The discovery of new particles helps us to understand how the universe works. Accomplishing this takes two steps: (i) we have to discover the new particles, and (ii) we have to discover the new theory or symmetry that gives rise to them. The LHC is tailor-made for the former and has an expansive discovery reach for new states. However, the latter requires a more delicate touch — precision measurements of a particle’s properties are needed to learn about the underlying theory. Enter the ILC whose beams are fundamental particles with a known and tunable initial quantum state, enabling ultra-precise measurements. There have been literally thousands of physics studies for the ILC and several large review volumes such as here, here, here, and here (non-technical). I’ve been involved in these studies for ages — I wrote my first ILC paper as a graduate student in 1988 (I was the first to show the reach for new gauge bosons) and either wrote or contributed to the new physics chapters in each of these review volumes. I truly believe we will need high energy electron-positron data to fully understand the physics that awaits us at the TeV scale.

An awe-inspiring physics case isn’t worth much unless it can be matched by the technical feasibility to build the machine. Our hard-working accelerator friends have been studying this mahcine for decades as well. Ideas began to mature in the mid-1980’s when folks understood the basic accelerator concepts for a high energy linear collider and thought one could be realized with a finite amount of research & design. During the next decade, four leading concepts for the accelerating mechanism emerged: (i) TESLA, based on superconducting Radio Frequency accelerating cavities, (ii) NLC/JLC-X based on high frequency (11.4 GHz) room temperature copper cavities, (iii) JLC-C based on lower frequency (5.7 GHz) conventional cavities, and (iv) CLIC based on a two-beam scheme with high gradient room temperature cavities and transfer structures operating at 30 GHz.

Research progressed on these four designs for over a decade and several reviews to evaluate them were undertaken. In 2004, after the physics consensus document was signed, the international community came together and formed a panel to make a recommendation for a RF technology between the superconducting and room temperature cavities. (CLIC was viewed as requiring significantly more R&D to demonstrate feasibility.) The panel chose the cold technology citing, amongst other things, a higher reliability and further progress on industrialization of the components. This choice was promptly accepted by all groups involved and is viewed as a major milestone towards a global realization of the project.

At this point the Global Design Effort (GDE) was formed, headed by Barry Barish of CalTech. About 100 accelerator physicists worldwide participate in the effort. Their first task, known as the baseline configuration, was to choose the parameters for all of the components and subsystems of the 500 GeV machine. Parameters like the accelerating gradient of the cavities (35 MeV/meter peak and 31.5 MeV/meter operating), the length of the accelerator (31 km), the capability to polarize the positron beams (yes), etc. were decided upon. This was completed by the end of 2005, so that the GDE could spend 2006 writing the Reference Design with full costing. I’ll write a step-by-step guide to the accelerator design soon — it’s a story in itself and constitutes a major technological feat. The Reference Design was released today, and now the next task for the GDE is to evolve and improve the design through continuing R&D and value engineering. They hope to make engineering choices for further optimization of the performance relative to cost. This process will take two to three years and will lead to a detailed Engineering Design Report, which can be used for the actual construction of the ILC. The estimated time for construction is seven years, after the project has been formally approved. Here’s a schematic of the GDE timeline:

The big news from today’s document release, the question that has held everyone breathless for years, is the cost. The cost was given in international value units. Each region (Europe, Asia, Americas) has its own peculiar costing scheme, and the trick was to present a cost that can be translated to each of them. So, the cost is….insert drum roll here….

  • $1.9B ILC Value Units for site-related costs, such as tunneling
  • $4.9B ILC Value Units for the value of the high technology and conventional components
  • 13,000 person-years for the required supporting manpower
  • ILC Value Unit? This is new terminology for a currency exchange rate! Their definition is 1 ILC Value Unit = 1 US Dollar in 2007 = 0.83 Euro = 117 Yen.

    It is critical to realize that this costing scheme is most similar to that used in Europe. The $6.7B figure does not include labor or contingency, which we include in the project cost here in the US. There are standard factors that are usually employed to estimate the translation to the American accounting scheme, which invites everyone to do their own calculation. This can lead to rather disparate results. To have a firm, standarized US cost estimate, the Department of Energy and the American Linear Collider Steering Group are performing their own translations of the GDE costing to US accounting procedures. The only thing we know for sure at this point, is that once labor and contingency is included, it will be more than $6.7B. Oh, and don’t forget that we need to include the cost of the detectors too. So, stayed tuned….

    Today’s press release can be found here, as well as articles in the New York Times, and Science, as well as a movie starring my good friend and wine-consuming buddy Phil Burrows being interviewed by the BBC.

    CATEGORIZED UNDER: Science
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    • http://theeternaluniverse.blogspot.com Joseph Smidt

      Great Post. If I was going into engineering I think I would would love to design and build these accelerators.

    • http://www.valdostamuseum.org/hamsmith/ Tony Smith

      JoAnne, thanks for defining the ILC value unit.
      (Does the necessity for it mean that the US dollar’s status as primary world reserve currency is doomed?)

      Over at Peter Woit’s blog when I commented that in my mind a sufficient reason to build the ILC was that even if no new physics is found, the ILC could verify the Standard Model to much greater precision, and that would be significant,

      wab replied to my comment saying:
      “… My colleagues also argue … about high precision measurements of the standard model. That arguement may sell to high energy physicists but I think it will be a hard sell to the other parts of the APS, let alone the general public …”.

      I was disappointed to hear that “other parts of the APS”, not to mention “the general public”, would not care about finding out how precise might be the Standard Model’s accuracy in modelling nature’s particle physics.

      Whatever happened to the days of Benjamin Franklin (or was it Faraday?) when people could reply to demands for proof of usefulness of new stuff by saying:
      What use is a newborn baby?

      Tony Smith

      PS – I have said it in other comments on this blog and on Peter’s blog, but I still want to emphasize that I think that the USA would be better off by cancelling a new aircraft carrier (CVN 78, aka big target for missiles) whose construction cost is stated as $8.1 billion and whose total ownership cost is stated as $26.8 billion, and using that for ILC.

    • graviton383

      Nice job , JoA!

    • http://definitions.wordpress.com Joshua R

      Terrifyingly cool.

    • amanda

      Hmmm… for that $6.7B we could probably fund two weeks of democracy building in Iraq… It’s a tough call.

    • http://blogs.discovermagazine.com/cosmicvariance/joanne/ JoAnne

      Tony: The use of the ILC value unit is merely a result from the ILC being a truly international project. You gotta admit, it wouldn’t seem quite so global if everything was quoted outright in US dollars.

      I agree with you completely on the scientific merit of the project, regardless of what is found at the LHC. However, it is a lot of money, and we have to provide a compeling argument to spend that much of the public’s money.

    • http://crew.org iba

      glad to know finally collider experimentalists are no longer nilpotent as in the past decade in greatly improving our understanding of nature.

    • Jeff

      Tony
      My impression (as a lowly grad student) is that the complaints from physicists of the non-particle persuasion have a lot to do with “bang for your buck”.

      Particle physicists are expensive critters – an experiment like CDF at the Tevatron costs a few hundred million dollars (it’s hard to find an exact figure) and employs more than a thousand people. Over its lifetime it produces a few hundred publications. Some other scientists get annoyed with that cost-per-result ratio, and think of how much they could do with that money. The ratio could be even worse for more special-purpose experiments – MINOS probably produces fewer results-per-dollar than CDF, for example.

      This assumes that all publications are created equal, of course. I would argue that particle measurements are of broader interest than some others, and that it’s worth the extra cost.

    • http://blogs.discovermagazine.com/cosmicvariance/john John

      (13,000 person years) x ($100k/person/year) = $13 billion

      Now, not all people will cost $100k. But when you include benefits and the typical costs of overhead and support staff, it’s probably not far off. So…20 billion value units?

      This would be spread over about 10 years, or 2 billion per year. The US, if it hosts the machine, would have to cover perhaps half of that. That represents more than a doubling of the present high energy physics budget in the US…and in my opinion, that would be a laudable goal.

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    • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

      I don’t think that bang-for-your-buck is the right way of thinking about it, but I don’t think that the best motivation for spending billions on particle accelerators is that the results are somehow better or more interesting.

      The point is that the only way to learn about high-energy particle physics is to spend billions of dollars. At least, that’s the only way we know of to get the detailed information that really gives us clues about the next level; astrophysics and tabletop experiments can teach you something, but they’ll never find the Higgs boson(s), for example. If you decided to spend only half as much as the ILC would cost on building an accelerator, you wouldn’t learn half as much — you would learn nothing. That’s just the price of playing the game. Whereas, if you were funding a thousand smaller experiments and cut half of them, you might expect to get half the results.

      And, regardless of the relative level of interestingness of particle physics compared to other fields, a lot of people think it is interesting in its own right. If we want to learn this stuff, we need to spend the money; whether or not it’s worth the money is an interesting question worth debating. (I think it is!)

    • http://www.math.columbia.edu/~woit/wordpress Peter Woit

      John,
      Given my training in advanced mathematics, I see a problem with your calculation.

      The ILC total looks to me more like $10 billion ($1.3 billion for people), or, $1.4 billon/year for the seven years it is supposed to take to construct the thing. If one (optimistically…) can get other countries to pay half, the US half is more or less the same as the current total US HEP budget. So, in principle, all you have to do is shut down all the rest of the HEP program… More realistically, you don’t need to double the HEP budget (funding everything going on now + ILC), but you do need some sizable increase if you want to fund the ILC + some reasonable amount of other HEP research.

    • Matt

      JoAnne, I am curious whether any other accelerator techniques have been considered for the ILC beyond those four listed. A bunch of fascinating work has been done with plasma wake fields over short distances. Is the study of this phenomenon and its associated technology still too much in its infancy to be considered a viable option for the ILC?

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    • http://blogs.discovermagazine.com/cosmicvariance JoAnne

      Matt: There is indeed some very exciting research going on in advanced accelerator technology. Stuff like plasma wakefields as you mentioned and my favorite, plasma afterburners. These technologies are not yet ready for primetime and it will be awhile before there are. But this research is absolutely critical to the future of particle physics and in my opinion it should be better funded.

      Jeff: The reason that the bang for the buck argument doesn’t work is that science funding is not a zero-sum game. If some fancy new accelerator project doesn’t get funded, the monies do not transfer to other areas of science. Instead, they transfer out of science and science as a whole is the loser. We learned this lesson with the cancellation of the SuperCollider.

    • http://blogs.discovermagazine.com/cosmicvariance/john John

      OOPS! I did count an extra zero there, didn’t I…sorry!

      Well, that’s a lot better, isn’t it?

    • Robert Musil

      What indications of support and/or interest have been made so far on behalf of any government that might be expected to fund or host the ILC? A very interesting comment posted on Peter Woit’s blog indicates some interest has been expressed in Japan.

      Tony Smith asks above: “Whatever happened to the days of Benjamin Franklin (or was it Faraday?) when people could reply to demands for proof of usefulness of new stuff by saying: What use is a newborn baby?”

      Perhaps those days were numbered when the public realized that newborn babies don’t cost well over $10 Billion each? Just asking.

    • http://www.valdostamuseum.org/hamsmith/ Tony Smith

      JoAnne said “… I agree … completely on the scientific merit of the [ ILC ] project, regardless of what is found at the LHC.
      However, it is a lot of money, and
      we have to provide a compelling argument to spend that much of the public’s money. …”.

      Sean said “… The point is that the only way to learn about high-energy particle physics is to spend billions of dollars. …
      that’s the only way we know of to get the detailed information that really gives us clues about the next level …
      If you decided to spend only half as much as the ILC would cost on building an accelerator,
      you wouldn’t learn half as much – you would learn nothing.
      That’s just the price of playing the game. …
      If we want to learn this stuff, we need to spend the money;
      whether or not it’s worth the money is an interesting question worth debating. …”.

      So, as Sean says, we humans either build something like the ILC
      or “learn nothing” about “the next level”.

      As to what might be a “compelling argument” in “debating … whether or not it’s worth the money”, maybe it would be a good idea to base it on some really big possible thing that might await us at “the next level”,
      so
      what about:

      1 – We know from astrophysics that 3/4 of our universe is Dark Energy;

      2 – Dark Energy is related to gravity, and strong enough to expand our whole universe;

      3 – Higgs, by giving mass to the Ordinary Matter that makes up 1/25 of our universe,
      is also related to gravity;

      4 – A Great Question is whether or not mutual connections to gravity might give a connection between the Higgs (and consequently the Standard Model) and Dark Energy;

      5 – Detailed study by ILC of the Higgs (and the Standard Model) MIGHT show such a connection and MIGHT even point to a way to control Dark Energy
      (in analogy to the way detailed study of nuclear reactions due to radioactivity gave Lise Meitner the idea of nuclear fission chain reactions); and

      6 – Controlled Dark Energy might be as big an advance over Nuclear Energy
      as was Nuclear Reactors (nuclear energy) over Fire (chemical energy).

      That argument might be a long shot,
      but
      probably no longer than nuclear fission chain reactions would have seemed to be at the time of early observations of radioactivity
      and
      it brings together astrophysics and particle physics
      and
      the quest for control of Dark Energy (whether or not it eventually succeeds in the direct sense) is a clear BIG objective that could inspire people to undertake a peaceful great project – the ILC.

      Tony Smith

    • http://blogs.discovermagazine.com/cosmicvariance JoAnne

      OK, this is my third attempt to submit this comment – I’m being caught as SPAM on my own post!!

      Robert: Ray Orbach, undersecretary of science for the US Department of Energy, has publicly stated enthusiasm for the ILC and expressed his support to construct it in the US if the price is right. In fact, the ILC is the top-priority mid-term project in the DOE 20 year strategic plan. Now the question is whether the price is right. The 20-yr plan can be found at http://www.science.doe.gov/Sub/Mission/Mission_Strategic.htm (my hypothesis is that including this as a link tripped the SPAM filter).

      Tony, as I said, there are literally thousands of physics studies for the ILC, including most of what you suggest. Take a look at one of the reviews I quoted.

    • Belizean

      Jeff wrote:

      My impression… is that the complaints from physicists of the non-particle persuasion have a lot to do with “bang for your buck”.

      Sean wrote:

      I don’t think that bang-for-your-buck is the right way of thinking about it…

      JoAnne wrote:

      Jeff: The reason that the bang for the buck argument doesn’t work is that science funding is not a zero-sum game. If some fancy new accelerator project doesn’t get funded, the monies do not transfer to other areas of science. Instead, they transfer out of science and science as a whole is the loser.

      Clearly, “bang for buck” is the only rational way to determine scarce resource allocation. The form of the problem, of course, is to allocate resources is such a way as to maximally contribute to some property X. Sean has implicitly defined X as human knowledge of particle physics. Joanne has implicitly defined it as the whole of scientific knowledge. Tax payers through their representatives could well have other definitions for X according to which it might be perfectly rational not to fund the ILC at all.

    • WeemaWhopper

      How enticing to accelerator physicists and experimenters… to be thought of as a cost of 13,000 person-years. Perhaps we can train Chinese and Indian students to do the job for only $10,000/person-year. Let’s add the 5,000 person-years of theorist and phenomenologist time that will go into writing lots of postings about the possible and real results… again, would be delightful (and probably effective) to outsource that work.

      By focusing very publicly on cost and design, the ILC has shot itself in the foot. People generally support great, visionary, sweeping projects. Not everyone… I remember marches in the late 1960’s to the effect that why are we spending money going to the moon when children in the US were subsisting on lead paint chipped from tenement walls… but witness the Iraq debacle. Lots of folks in the US still buy into the vision, and the Bush Admin has largely kept the cost and design buried. Odd that no demonstrators are regularly at the gates of General Dynamics for this war… they were during the Vietnam War. Proof of the successful PR slight of hand for the $500 billion or so squandered so far in Iraq.

      What distinguishes particle physics is that its great vision has generally come in only 40-50% above budget. NASA? Probably 300% above budget. Iraq? 1000% above budget. Yet in particle physics we saddle ourselves overmuch with cost and budget. We should sell our vision, and simply reassure that we are dead serious in our design and costing. It is futile to refight the battle of Waxahachie… the real lesson of Waxahachie: keep ex-Military contractors out of the management team.

      But if LHC finds nothing, it may well be the next step should rightly be another hadron machine. Depends on the mode of failure at the LHC… if the experiments are clean and capable, which is by no means proven yet, and if there is no new physics, another hadron machine is a smarter choice… more bang for the buck. But if LHC is kind of fiasco of `Nobel Dreams,’ sloppy backgrounds, blackened detectors then… ILC forever.

    • gbob

      “we should sell or vision” and keep mum on how much the thing actually costs? Get real. No government in its right mind is going to sign off on a megaproject like ILC without knowing what it costs. Would you buy the latest version of the Ginsu Knife, no matter how well it slices aluminum cans, if they didnt tell you the price? Or better, if they only told you “well, at least its *much* cheaper than an aircraft carrier”?

      Of course the vision has to be compelling; that’s necessary but not sufficient. Arguments like Higgs–>Dark Energy–>new energy source don’t even pass the ha-ha test, at least not right now. The best sales pitch for the ILC will be if the LHC finds something that’s completely unexpected — another “who ordered that?” moment — that can be studied to death with the ILC. Finding nothing at all would generate a lot of work for theorists, but its hard to generate a lot of public excitement or bucks to go explore nothing (the manned space program notwithstanding).

    • Yo

      Hey,

      I was curious why the energy seems so low. I mean 500 GeV?! They can so do better than that! Maybe I am just spoiled after looking at the Tevatron and the LHC. Is there a particular reason for that energy or is it because they are not focusing only on the High Energy Spectrum and this sort of borders High and Medium?

      Any info anyone might know would be appreciated. Thanks.

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