Christoph Leemann is an old hand at the Thomas Jefferson National Accelerator Facility, or as it is commonly known, Jefferson Lab. He came to the Department of Energy (DOE) lab located in Newport News, Va., to help design the machine at the center of the facility just then taking shape — the Continuous Electron Beam Accelerator Facility (CEBAF). Leemann arrived in 1985 — 10 years before the first experiment would take place there.
Nuclear physicists had been clamoring since the late 1970s for an accelerator that could provide an essentially continuous beam of electrons to enable them to study the atomic nucleus, and Leemann took responsibility for the construction of CEBAF's new superconducting accelerator.
He stayed on through the years under founding director Hermann Grunder, rising to the post of deputy director in April 2000. Just a few months later, Leemann assumed the position of interim director when Grunder left to become the director at Argonne National Laboratory.
While the search for a permanent director continues, Leemann remains as interim chief at Jefferson Lab, which has grown to a $100-million facility. Not only is he watching over plans to upgrade CEBAF to 12 giga-electron volts (GeV), Leemann is also guiding the lab's emerging efforts to develop and field a high-power free electron laser (FEL) with a variety of defense and industrial applications.
In one of NTW's occasional "Leaders in Science" interviews, Leemann sat down in his office at the lab to speak with Editor Scott Nance. This week, we present excerpts of that discussion in Part I of the interview:
Q: What's going on at the laboratory today and where's it going in the next few years?
A: ...We are still, in the DOE's eyes, a single-program laboratory aimed at nuclear physics. Nuclear physics is certainly going to be our mainstay, our primary customer, [and] our bread and butter for hopefully quite a while.
However, we are in a situation that is very, very competitive. The '01 [budget for DOE's overall nuclear physics program], as allocated, was $360.5 million. The '02 House mark is a million more than — only a million more, which means you've got to eat all the inflation that comes to pass. The Senate version is $12.5 million higher. We don't know yet what will come out of conference.
There's report language that says, "This [additional] money should be used for more-efficient operations at two places," namely [the Relativistic Heavy Ion Collider] at Brookhaven [National Laboratory] and CEBAF here at Jefferson Lab.
We hope at least some of it will stick here.
Q: What does that mean, "more efficient operations"?
A: That means: be able to improve a few technical components to make them more reliable. It may mean we run a few more weeks [out of the year]. But, the bottom line is: it should allow us to produce more live, good physics hours. Whether that is by running longer or by decreasing downtime, that's to be seen.
As long as you assume the same outcomes as desired — as long as you shoot for the same goals — this funding level leaves us rather strapped. That is a sort of a subsistence level. We may be able to learn a few more efficiencies, but I think we're pretty lean and pretty close to how much we can squeeze out of every dollar.
I know that hard-nosed business types come in with the expectation that you can always find at least 10 percent fat — if not 20. I don't believe it's 20 [percent at Jefferson] — in fact, I know it's not 20. How much there is, we will just simply learn as we try to shake this out.
Q: But you don't sound like there's even maybe 10 percent.
A: I don't believe in 10. It's going to be a tough job to find five.
Q: Well, then, what's that mean to be running on a subsistence level?
A: That would mean less of a research program. We operate three [experimental] halls. We don't have three halls simultaneously running all of the time — but a good fraction of the time. We could scale it down where we only run two or less, for instance. That's an example of how we can ease the pressure on a number of resources... While operations would be maintained at a quite-decent level in terms of quality, the total output would be reduced. Few [scientific] papers would come out [based on Jefferson Lab research].
Another area is, of course — and that's a very critical area — we still spend a certain amount in R&D areas in a number of core skills. We have the superconducting technology — that's probably our strongest asset. We have a few other things. At this time we don't want to jeopardize those. In a very, very hard situation we could be forced to reduce those activities. That is something I would fight tooth-and-nail because that would really mean a significant downturn.
Q: What would happen if you had to cut those areas?
A: You would admit your prime-time is over, or something like that. From a business point, we shouldn't do it. Period.
Q: How do you turn things around?
A: How do we turn it around? By trying to find new customers, and by trying to advertise that we are, at this moment, the prime keepers of certain skills, certain core technologies, that will be called for in virtually all the accelerator projects that are being talked about.
Let me be more specific. We have two or three things here — let me use three. Most important is the superconducting RF [radio frequency] technology. We are the leader in the U.S. I am reluctant to say that we are the world leader — we just haven't invested [enough]. The world leader, in my opinion, today is — I'm not sure it's politically correct to say it — is DESY [a large German lab] in Hamburg. They have invested a huge amount over the years. They may be the best...
But we are the [best] in the U.S. in superconducting RF technology, clearly. Second, we have developed a [free-electron laser]. We have demonstrated at the FEL the concept of energy recovery. Third, I think we are probably the leading place for the development of high-current, high-brightness [continuous wave] electron beams...
Now what does that mean? It means that there are five to six projects talked about that all would make use of some or all of these technologies. [DOE's] nuclear physics [operation] plans to build the Rare Isotope Accelerator ... That needs the superconducting technology.
Going on to Brookhaven, there is a proposal to greatly increase the "luminosity" of RHIC by a number of tricks. One of those tricks involves what is called "electron cooling."
One way of making those beams at RHIC denser would be by this trick called electron cooling which is very simple. People have observed that if you send an electron beam parallel with a proton beam or an ion beam, and if the electron beam is "cool," which means it has very little internal motion, then there is a transfer of the higher degree of internal motion of the proton beam to the electrons. And if you keep repeating that, you could replenish the electron beam — or you keep it "cold" — and then the proton beam gets cooler which actually manifests itself by its dimensions shrinking...
This has been tested at lower energies — lower energies meaning for the electrons, half a MeV [mega-electron volt] or something like that. For RHIC, one would need an electron energy of about 100 MeV. It turns out that our FEL — the 10-kilowatt upgrade when it's done — is very close to what is needed there. It has about the right energy, it is recirculating — which means you throw the old beam away and you continuously have a fresh one, which in the terms of cooling means a cold beam. What we would have to work at is the beam intensity — we would need about 10 times more out of the gun than we currently. But it can be done. This would be a near-term application of this technology...
On a much grander scale, these recirculating [linear accelerators] have been proposed for much higher accelerator energies. There must be at least three light source proposals on the way that [could use] the recirculating linac — I should say energy recovery linac — as the main machine.
Brookhaven is thinking of one and Argonne must be thinking of one — and in the [National Science Foundation] fold — Cornell [University] is thinking of one...
Q: Where do you see this lab's role or niche within the entire DOE lab complex?
A: First of all, we clearly plan to remain a strong player in nuclear physics — the current minimal budget notwithstanding. That's a bigger problem that all of basic science has to deal with, and we'll see where it goes. I see certain trends.
In order to do that, we want to do our 12 GeV upgrade... It basically means doubling the energy of the installed machine, adding a new experimental hall, and pursing a new level of nuclear science with that. Clearly, we would like this to remain our main stay — that's why we're pushing hard.
We also see ourselves as we hope we can remain — or become — the provider of choice for certain accelerator technologies, mostly notably that of superconductivity and energy-recovering linacs.
The third leg, of course, is that based on the FEL we hope we can build up a material — or let me say, a photon — science component to our program.
Submitted: Monday, August 13, 2001 - 12:00am