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Credit: Yiming QIU for NIST
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Interview of Dan Neumann by David Zierler on June 11, 2020,Niels Bohr Library & Archives, American Institute of Physics,College Park, MD USA,www.aip.org/history-programs/niels-bohr-library/oral-histories/45458
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In this interview, David Zierler, Oral Historian for AIP, interviews Dan Neumann, Group Leader for Neutron Condensed Matter Science at the NIST Center for Neutron Research. Neumann recounts his childhood growing up on a farm in Nebraska and later on in Arizona. He discusses his undergraduate experience at Arizona State and his developing interest in condensed matter physics. Neumann describes his graduate work at the University of Illinois, and he describes his lab work, his AT&T fellowship and research at Bell Labs, and his dissertation work under the direction of Hartmut Zabel. He explains the circumstances leading to his appointment at NIST, and he describes the value of neutron scattering as a means of understanding materials at atomic, nanoscale levels. Neumann describes how neutron scattering fits within the overall mission of NIST, and he explains NIST's support for basic science and why its laboratories have attracted a wide array of researchers. He explains how neutron scattering is the key to developing new materials for both research and commercial applications. Neumann describes some of the key interagency partnership that have advanced neutron scattering research, and he explains some recent projects he has been involved in, including hydrogen fuel cell research, dynamic work on proteins, and pharmaceutical work. At the end of the interview, Neumann describes how closely his work at NIST has been integrated within the broader physics community.
OK. This is David Zierler, oral historian for the American Institute of Physics. It is June 11th, 2020. It is my great pleasure to be here with Dr. Dan Neumann. Dan, thanks so much for being with me today.
OK. So to start, please tell me your title and institutional affiliation.
So I am the group leader for Neutron Condensed Matter Science at the NIST Center for Neutron Research at the National Institute of Standards and Technology. I'm also the director for the Center of High-Resolution Neutron Scattering, which is a partnership between NIST and the National Science Foundation.
OK, great. Let's now take it right back to the beginning. Tell me a little bit about your family background. Where are your parents from?
So my parents are from northeast Nebraska, a little town called Creighton. And I was born in Creighton. We lived on a farm just outside an even smaller town called Winnetoon, Nebraska. And we lived there for some time. I went to a one-room school when I was in kindergarten through second grade, in Winnetoon. And then when I was older, we were bussed into Creighton, where I went through middle school. And then my parents moved to Arizona, and so I went to high school in Arizona, Bradshaw Mountain High School. At the time it was in Dewey, Arizona, outside Prescott. And I graduated there and after that went to Arizona State.
Now, as a kid in Nebraska, was it a working farm that you grew up on?
Yeah, yeah. It was a working farm. It was a very diverse set of crops and animals and all this sort of stuff. So it was pretty cool. I learned lots of things there, you know, how things worked, and equipment. And I liked the machinery and all those sorts of things, as you might expect. So it was good. I was always interested in science. My parents didn't go to college, but I was always interested in science. I had an uncle who was a food scientist for General Mills. So it seemed like that was a possible thing, to be a scientist.
Now, had your parents done—was there a long line of farming in Nebraska going back?
Yes, there was. I don't remember exactly when they all showed up, my ancestors in Nebraska, but basically the late 1800s.
So the Neumann part of the family came to the U.S. in 1848 and settled in western Illinois. And then there was some of the family that moved later to Nebraska for more farmland.
I assume your parents changed professions when they moved to Arizona.
Yeah. So my dad, when we moved, he did carpentry work for a while, but then he started a garage door business. So I spent summers installing garage doors and garage door openers. [laughter] All the way through college.
Now, in high school, were you stand out in math and science?
Yeah. So it was a very small high school. There were forty-two in my graduating class. I liked math and science. I had a great high school science teacher, who actually had a bachelor's degree from Michigan State in physics. And so that was what really, I think, sparked my interest in becoming a physicist. And yeah, I was a valedictorian of the class, and all that sort of stuff. But I think that the high school experience there, even though my high school physics class had, I think, six people in it, it really inspired me to become a physicist. And the teacher really encouraged me that I could do this, and it was going to be OK.
Now, choosing Arizona State. I assume it's both because it's close, it's good tuition, and they do have an excellent physics program.
Well, I don't know about the excellent physics program. I knew, at that time, that to be a physicist you had to go to graduate school. And I didn't think it was going to matter all that much where I was an undergraduate, to be honest with you. And I had a full tuition scholarship to go to Arizona State. My parents weren't wealthy people. And I had other scholarships to help pay for room and board. So it was relatively inexpensive for me to go there. Actually, it was a really good choice. I had a great time at ASU. The professors were really kind to me. Very supportive of me. The physics program did not have that many undergraduate students. So you make good personal relationships. The professors were very open in talking to you. They had office hours and stuff that like that you could go to. And they would meet basically whenever you wanted to and talk to you. So it was great. It was really a great experience. I learned a lot. And I became a condensed matter physicist because I took condensed matter physics when I was a senior. I liked it a lot. And I really liked crystals and symmetry and all that sort of stuff, and so I decided I'd become a condensed matter physicist. And I went to Illinois for that reason.
Right. Of course. So obviously, by the end of your undergraduate, your personal identity as a physicist was pretty well defined in terms of condensed matter.
Yeah, but it was towards the end of the undergraduate process when I really decided that's what I wanted to do.
The terms solid-state and condensed matter. Can you remember back in terms of how those were used back in, you know, the early 1980s?
Yeah. So solid-state was the most common term back then. And it was really for solids. I mean, it was really things that were solid. And condensed matter basically included liquids. So like quantum fluids, liquid helium, those sorts of things. And so condensed matter is a bit broader term than the solid-state. And so that was the genesis. In those days, that was when it was converting from solid-state to condensed matter.
Right. And so I'm just curious to fast forward, how have those terms been used in different ways in the past thirty, thirty-five years?
I think everybody says condensed matter now.
Which begs the question, what happened to solid-state?
It was basically subsumed into the condensed matter. It's still there. It's still part of condensed matter physics. But condensed matter is a broader term.
Right. And so what was it about the field that was so compelling and interesting to you?
I'm not exactly sure. I really did like the idea of crystals and symmetry, and you could use that to understand lots about a material, with just relatively straightforward, though mathematically complicated, but straightforward concepts. I think that was really a good part of it. And secondly, I think that I always was more interested in, shall we say, use-inspired research. I was always interested in that. Where you have an idea, and while it’s interesting physics, you know what in the future this could be used for, this material or the work you're doing. I think that was always part of my interest.
Kind of makes sense between farms and garage doors that you wanted to do something with your hands, probably.
Yeah. So I think condensed matter physics is often use-inspired. I still appreciate that aspect of the field. I think it's still an important part of what I really enjoy about my job.
Now, with Illinois, was your sense simply, this is arguably the best program in the world for condensed matter and go for it? Was that basically how that worked?
I think so. I think that was part of it. It was certainly their emphasis there. There are other universities that are equally good or very similar, at least, in that area. I don't think, at that point, I was ready to go to the East Coast. I was familiar with the Midwest. It seemed good. In 1981, I think it was, the APS meeting was in Phoenix. So I spent a lot of time there. And I chatted with a few of the professors from Illinois, and they encouraged me, and so I decided to go there.
Was there a particular professor you wanted to work with there, or it was the whole program that was attractive?
No, I hadn't made up my mind at all exactly what I wanted to do or who I wanted to work with. It was just generally going to Illinois.
And so what were your impressions of the department when you got there?
Well, it was a little…
It was much bigger than Arizona, I assume.
It was much bigger. It was very big. There were lots of students. The students were from all over. There were lots from the MITs and other famous places. So it was a little intimidating at the beginning. They put us in these big rooms with lots of desks, and I was able to make friends with a guy named Joe Ross, who did his undergrad at Yale. And I think some of that sort of stuff set me at ease. Joe's now a professor at Texas A&M. And I think I settled in pretty quickly thanks to my interactions with the other students, but it was a little intimidating at first.
What was the ratio, in the first couple of years, between coursework and lab work at Illinois?
So Illinois had the attitude that, basically, you shouldn't be spending too much time in the classroom. You need to get your research done. And so the first year was basically classes. And after that, I think I took two classes, maybe, after the first year.
With a focus in solid-state, or it was still a pretty general education?
It was pretty general. I did take the solid-state physics course. I had Charlie Slichter for my professor for that, which I thought was great. I mean, he was a great teacher. So that was a very important class for me. But during that first year, I actually decided which group I was going to join. In fact, during my first semester. I was a TA for one of the big 10X courses, I don't remember what it was, and they ran the exams in the evening. They would bunch TA groups together to proctor one classroom. There was this young assistant professor named Hartmut Zabel who was TA-ing this course as well. Basically, you know, to lighten his teaching load, giving him more time to set up his lab and that sort of thing.
We had a relatively small room, and we were the only ones that had classes in this room where we were giving the exam. And so we chatted, and he was doing x-ray and neutron scattering. And that was how you saw the symmetries in crystals. So I was really excited about this. I was lucky enough to have a fellowship that would pay my first summer RA, so I didn't have to worry about him having money to pay me or anything like that. I said, "So, can I come and work in your lab?" And he said, "Sure."
Was this the AT&T fellowship that paid your way that first year?
That was a bit later. This was a University of Illinois fellowship. I was also TA-ing, but it was half the normal teaching load. And I was, to be honest, getting paid a bit better than the standard TAs. So it was a very nice deal. And then after that, then I applied for things like that AT&T scholarship. And I got that. And that was another great experience.
Now, I'm curious about the nomenclature there. AT&T and not simply just, you know, a Bell Labs scholarship. Was the idea here that it was starting to morph into more AT&T and less Bell Labs?
Well, Bell Labs was owned by AT&T, so I don't know exactly why they said AT&T.
This is coming up on the breakup of the monopoly.
Yeah. One of the things you could do, if you had this AT&T fellowship, is you could spend a summer Bell Labs. So I was there in the summer of 1984.
Which one? Where were you?
Murray Hill. So I was there in the summer of 1984, and it was in the process of breaking up. But the Bellcorp people were still in the building. In fact, they were completely mixed in. The only way you could tell them apart was that they had different badges, but it was all mixed up.
Was your sense—I mean, I've heard so much about Bell Labs from earlier days, in the '60s and '70s, where, you know, money was no object and the support for basic science was a hundred percent. Was that your experience, or was that already changing at that point?
I think it was still that way. Money didn’t seem to be a problem. However, they did control empire building, which basically wasn't allowed. Scientists had their lab module and as far as I could tell, were allowed put anything they wanted into it. But you couldn't have more space. And staff could have one employee working for them, which was either a technician, a lot of them had technicians, or they could have a postdoc.
So this was your spot for three summers, from '84 to '87?
No, just one summer. So you have either one, a technician or a post-doc, but only one. And it seemed that to me that the reason was that they were trying to get people to interact and work together. So it was really interesting. I learned a lot at Bell Labs. Some of it about physics, but lots about the sociology of science, in particular things I valued in a scientific work environment.
Was your experience that it was a place for great collaboration, where you could really just talk to people and learn about what they were doing?
Yeah. First, you have to realize, there were not many graduate students running around at Bell Labs. So this may not be everyone’s experience. But my experience was, if I was interested in something and I saw a paper by someone at Bell Labs, I could just walk down the hall, walk into their office, and they'd talk. And they described it. They'd give me more papers. They'd help me learn about it. It was really a great experience. It was very open. Again, there were clashes between certain people at Bell Labs that didn't get along. But they never really imposed them on me. I could just go wherever I wanted and talk to people. So it was a very, very good experience.
What were some of the most exciting projects that you were exposed to or were a part of at Bell Labs?
So I worked with Denis McWhan. I don't know if you know him. He was director of NSLS at one point. I worked in his lab, and we were working on BaTiO3. We were doing high-pressure experiments as a function of temperature on the ferroelectric phase transition. And this was all jury-rigged stuff. It was a huge pressure rig. I put dry ice baths and heater tape around it to try to control the temperature. And then we would use the sample as the spacer in a capacitor so we could quickly change the electric field on it, measure the dielectric constant, and look at the phase transition as a function of pressure and temperature and how that happened as a function of time after quickly jumping across the phase boundary. Denis had been doing some work on this with x-rays, but these were just bulk measurements. It was really a lot of fun working with Denis.
Joe Remeika, who is known for his growth of single crystal titanates, made the samples and deposited the electrodes on them. I broke the wires more than once, of course, with the high pressure. He was always so kind to replace them. Gabe Aeppli, who’s now the director of the Swiss FEL, was also on the project. It was really a good summer.
Did you self-consciously make any attempt to integrate that experience into your overall graduate work, or you looked at it as sort of an isolated, great experience?
The fellowship was great. I had my own travel money. I could go to conferences. That sort of thing. I don’t think I integrated into my overall graduate experience. But I learned a lot about the type of scientific environment I wanted to work in from that experience.
Right. So, to fast forward a little bit, was one of your takeaways from Bell Labs that when NIST came up, you were thinking, this is the kind of place where I want to be, as opposed to a national laboratory or an academic environment or something like that?
Yeah. The neutron facility at NIST had a similar open atmosphere, walking around, walking into people's offices and chatting about science, and all this sort of stuff. I like that a lot. And it was a neutron-scattering facility, which was one of my specialties. So I decided it was where I wanted to go.
How did you go about developing your dissertation topic, back in Illinois?
That's a complicated question. I don't think there was necessarily a development of a dissertation topic. What happened was, I joined this group and there wasn’t really a funded project because I had this fellowship. And so Hartmut Zabel, who was my PhD advisor, he had some samples that he had gotten from this guy, Hadis Morkoç.
And what was Hartmut's research? What was he working on?
He had two, really, things he was working on. He was working on graphite compounds, graphite intercalation compounds. You know, so kind of predecessors of doped graphene, or the MXenes that people work on now. And he was also working on semiconductor thin films. I did work on both while I was there. And so the semiconductors were mostly x-rays and the intercalation compounds were mostly neutrons.
So your dissertation was more like three or four papers stapled together, kind of thing?
Yeah. It was more than three or four, but it was papers stapled together, essentially. [laughs]
Who was on your committee?
So, there's David Pines, Don Ginsberg, and Jim Wiss who was a nuclear physicist. He asked good questions at the thesis defense. [laughs]
So you finish up in, what is it, the spring of 1987?
I finished up in the winter of '87. I got my PhD at the spring semester, but I finished up in January.
Now, when did you start at NIST? Was it before or after you defended?
That's a bit of a complicated question. My wife and I had started moving before I defended. I went back and defended and then came back and started work.
Oh, we missed that detail. When did you meet your wife?
In high school.
High school? So she was with you through college and graduate work?
Yeah. We got married before Illinois. So after college.
OK. So in terms of NIST, when was your official, your hard start date?
I think it's February 2nd, 1987.
And in surveying your opportunities, I'm curious how NIST sort of landed on your radar, in terms of the things that you were looking for.
NIST has a research reactor and I'd come out here and done a few neutron experiments with the people here.
During your graduate work, you mean?
During graduate work. And I'd traveled to NIST, then NBS, and done some experiments. So when they had gotten new funding to expand the facility, build a bunch of instruments, that sort of thing, it just seemed like a good time to join NIST.
What was so interesting about neutron scattering for you?
It tells me what I want to understand in a material, at the atomic and nanoscale. I think it's more my own personal kind of interest. And it's very versatile. You can do a lot of different things. You can look at the structure. You can look at how the atoms move around with inelastic scattering which is mostly what I did. So I think that was it—it tells me what I'm interested in in the material.
Now, I know you've worked on many projects, you know, throughout your career at NIST, but it seems like the home base has always been neutron research. Is that correct?
Yeah, that's it. I've been involved with neutron research my whole career.
So can you explain—it's a bit of a broader question. Can you explain how neutron research fits in within the overall mandate and objectives of NIST?
Yeah, sure. NIST is the nation's measurement laboratory. And so one of the main activities besides developing standards is developing good measurement techniques, good measurement technologies to measure what we want to know about the world. So what NIST normally does is develop a measurement technology and publish it, maybe patent it, whatever the case may be, to try to transfer that technology to the private sector or to academia. With the neutrons, you can't do that part of the tech transfer, because you have to have a strong source of neutrons. And so the way it works is we develop instruments for doing neutron experiments and we transfer that measurement technology by inviting the scientific community to come and use our equipment.
OK. So the neutrons are with you, and people come to you.
Right. So we are developing neutron measurement technologies, all the time, and providing them to companies and universities and other government labs. Sure, sometimes we copy ideas from other facilities, but we're continuously work to create new instrumentation for neutron measurements.
So how does understanding neutrons better allow for better measurements?
If you want to study a material, most of the techniques, particularly those that are going to look at the atomic scale and not the bulk properties, interact with the charge. There's a lot of electrons around and it's easy to interact with them. So most techniques interact with charge. And so they give you a particular view of the material. And while they're all complimentary, they're all kind of the same. Neutrons interact with the nucleus. So they give you a completely different view of the material. So the analogy I like to make is, people are familiar with going to the doctor, right. And you can get an x-ray. You see the bones. You see the heavy material. Most things we use to look at materials on the atomic scale look at those heavy things, see them preferentially because there are more electrons to interact with. Neutrons, on the other hand, interact with the nucleus, so they're more like the MRI. So they see the soft things, the hydrogen. Light atoms. A completely different view of the material. So NMR is the sister technique for neutron scattering.
I see. So in order to measure a material, you have to be able to see it. That's what you're saying.
You have to be able to see it somehow at the atomic scale, at nanoscale. You have to see how it's organized. You have to see how the atoms organize themselves. It's hard to understand how the material behaves if you don't understand what's in it and how atoms and molecules are arranged.
Dan, I wonder if you could walk me through, sort of in a narrative sense, from the beginning of the germination of an idea. You know, here's this material that we want to study and measure, and then walk me through that process of looking at it. And then on the other end of that process, explain how that is necessary to that broader mandate of NIST and measuring things.
OK. So, you know, materials development is key. Materials are a key part of any technology. They're essential to advancing technologies in the U.S.
You mean developing new materials.
So that means we have to develop new materials all the time. This is still done largely by, shall we say, insight and serendipity. There are very clever people who think about this and they say, OK, I think if I do this and this, I'll make this material and it might have the properties I’m after. And so they do that. But they don't know what they actually made. So they measure some bulk properties, maybe specific heat, maybe magnetic susceptibility, maybe they’ll put it in an x-ray machine trying to understand what the properties of this material are. They'll do all that in their own lab.
But they may need to know something else about the material. Maybe you want to know the magnetic structure. Neutrons have a magnetic moment. So you can actually see magnetism with neutrons directly. And so they'll write a proposal to use neutron instruments at NIST or some other facility. It gets peer reviewed and if it’s accepted, they'll come and spend a few days or few weeks at NIST, using our equipment, to get these microscopic insights into the structure and the dynamics of the material that tells them what they really did make, providing new insights to go back and perhaps make something even better. So that's generally the way that the materials development goes.
So does that mean that, at any given time, there are as many outside researchers on NIST's campus as there are NIST employees using the equipment?
So at our facility, there'll be more NIST employees because we have to run the reactor and all this other stuff and design new instruments and stuff like that. But all of our instruments would have external people using them most of the time.
And so, in terms of coming up with new materials, is that a challenge that is equally pursued by NIST employees and outside researchers?
Or are you generally relying on the outside researchers, and you're helping them pursue those goals?
So NIST doesn't do a lot of materials development. It's a measurement laboratory, so it develops new measurements for materials research. And so those materials are generally coming from outside, no matter where at NIST you're working. So the materials that we study are mostly coming from the outside. Sometimes they're in a collaboration with us. Sometimes they just send them to us, and we make the neutron measurements. Or sometimes, they just come and do the measurements themselves if they have enough experience and they don't need our help.
Can you give me a sense of some of the industries that are represented, in terms of the researchers who are coming to NIST to develop materials?
Yeah, sure. So I'll give you an example. We have a biopharmaceutical, a biologic that was developed by Amgen. They used our facility to help them understand the formulation. It's called T-VEC. It's actually the first live virus drug approved by the FDA. And they would neutron scattering to understand the issues with formulating this live virus as a pharmaceutical. This is on the market now, approved by the FDA, approved by the EU, and it's for late-stage melanoma. There are quite a few biopharmaceutical companies that develop biologics that use our facility.
There are companies that do more everyday things like Procter & Gamble. At our facility, they are usually look at shampoo. Shampoo is really complicated. There's lots of components. And with neutrons, since it interacts with the nucleus, you can highlight different parts of the sample by using selective deuteration. So chemically, it's identical, but to the neutrons it looks different. If you know where you put the deuterium, you can actually get a new understanding of the structure in a way that's pretty much impossible any other method. So they come and they want to understand, if I change the fragrance of my shampoo, what does it do to the structure at the nanoscale? Does it screw it up? Why is it not working right? What's going on? They'll come and do those sorts of experiments.
There are companies that build things using metals where we can measure the strains and the stresses and in a manufacturing part. So OMAX builds waterjet cutting machines. You know what those are?
And they have a little nozzle. We helped them develop that nozzle, with the right spraying profile, the right stresses in it, so it would be not cracked but still be effective in making a nice jet spray. So those are the kind of things we would work on.
Are the partners exclusively American companies, or do you invite international interests as well?
Industrial research is international. So most big companies have U.S.-based research efforts. Other countries outsource research to the U.S. So almost any big technological company has a research effort in the U.S. We have a consortium called nSoft, which is for the manufacture of soft materials. And companies can join this and get access at some level. And Toyota's a member, but it's actually TRINA. So Toyota Research Institute of North America, and they're in Michigan. And the people from Michigan come and use it but also people from Japan.
I'm curious if, given the fact that so much of this research is done for, you know, corporations who are looking to sell products, if trade secrets and non-disclosure agreements are a part of your world.
Yeah, they are. So I told you about the T-VEC drug. That was done under a CRADA. So the IP was all spelled out in advance. On the other hand, for the nSoft consortium, there's no IP allowed and all the research is open.
Why is that?
It's easier to separate things. The lawyers—if you have IP, you need to spell it out in advance. If there's no IP, we don't have to spell out exactly what we're doing. Now, if the company decides that there's something that they can do where they want to keep the IP, there's a separate mechanism for that requiring full cost recovery so the taxpayers don't subsidize private research. So if, say, TRINA, wants to do an experiment, and they think that this will give them a competitive advantage, and they don't want their competitors to know about it, they can buy time separately from the nSoft agreement.
And in terms of buying time, is that a metaphor, or is there actually money being exchanged for access to these labs?
Yes. Money is being exchanged.
Oh, so this is obviously, this would be a major funding source for NIST, I guess?
No, it's not, actually. This is a small part of what we do. The companies more often do things open.
Because they don't—
They can also learn what they want to know by doing something that's publishable. There are many companies that are very good at this. They are able to publish the results of the neutron measurements without giving away the thing they don't want to give away.
I'm curious about technology companies. What would be a case of a technology company wanting to come to your shop and learning about materials?
What do you mean by a technology company?
I mean, anything from, like, an Amazon or a Google to a device manufacturer.
We have a little bit of interaction with those things. A lot of times, many of those things they're doing don't really have a big materials component, like Google or Microsoft. Sometimes the technology companies will have a neutron component. For instance, all parts of your hard drive were looked at with neutrons, often at the NCNR, but also other neutron facilities around the world. Now, of course, hard drives are a commodity. So there isn't much effort on research on them anymore. So, yeah, we'll have some technology companies, but sometimes the things can be done with x-rays. And people would generally prefer doing them with x-rays because they have an x-ray machine in their home institution. No travel involved, and it's easy to control information flow if you're a company.
Now, on the commercial side, looking back over the course of your career, is there any product that you worked on that was the most personally satisfactory or that you were most proud of in terms of its societal value?
I worked on lots of different things over the years. I don't know that any of them have been that useful, generally. I worked with Federal Highway Administration for a long time studying concrete with neutron scattering. I enjoyed that a lot. I learned a lot about concrete. [laughter] But I don't know that that's been incorporated. Concrete was first made as Portland cement 200 years ago. And so by Edisonian approach of trial and error, a lot is known about it. So everything is pretty well optimized just by long experience. But you can actually understand why it is that way. It's amazing how little research is out there in some of these cases. And now there's a lot more interest in concrete research, particularly in Europe, because concrete is a calcium-rich material. And so they get the calcium from calcium carbonate. Basically, we make calcium oxide by just heating the stuff up, and the carbon dioxide goes out the chimney. So a lot of carbon dioxide is made by manufacturing concrete.
So I specified commercial because my next question was your collaborations within the government. Who are some of the most important federal partners that you've worked with?
OK. So our most important federal partner is the National Science Foundation. I mean, we have this facility that is of great interest to the academic research community. So there are a lot of academic researchers. In fact, most of the use of this facility is by academic researchers. And so the National Science Foundation helps us operate some of our best instruments - those that are most interesting to the academic community. This partnership allows us to run people through very efficiently at a great rate with access based on peer-reviewed proposals. That's our most important partnership. I had the one for a long time with the Federal Highway Administration that was personally important to me. We have a longstanding partnership with EERE, part of the Department of Energy. Let's see, what else do we have for federal? We a lot of interactions with NIH. So those are, I guess, the big ones.
What kind of work has the NIH wanted to do at NIST?
Well, users from NIH come and they work on all kinds of things. For example, there's a lot of work on the interaction of alpha-synuclein with bio membranes. This is often called the Parkinson's protein as it’s long been implicated in this disease. Right now, we have a paper in review on K-Ras, which is a signaling protein that works at the membrane that's implicated in almost all cases of pancreatic cancer and other cancers as well. NIH has a huge program to try to understand and control K-Ras. And so we're just a small part of this. But they do neutron work as part of that big program, to see K-Ras. Basically, neutrons allow you to see the protein and what it's doing right at the membrane, where it would be functional in a biological system. There was just an article about neutrons in biology in Physics Today. I may have sent this to you.
What about the military? Does the military ever need NIST facilities?
Yeah, sure. The Navy and the Army, both regularly do things at NIST. The Navy, a few years ago, was working on explosives and basically looking at porosity which has to do with how stable the material is. You want explosives to be stable, but you still want them to go boom. So they would be looking at porosity, trying to understand that relationship. There were quite a few papers on that topic from the Naval Surface Warfare Center. The Army is working with us on batteries. There's a big battery push to get batteries in extreme environments so that war fighters could carry them to power devices.
No more diesel generators in the middle of the desert.
Right. So there's a big program on that with the Army Research Lab at Adelphi, and we have people working on that with them and the University of Maryland.
I'm curious if the military work requires a clearance for any of those projects?
The answer is no. We have very few people at our facility with clearances. There are some that are involved in running the reactor operations.
The emphasis has been on all of these people who are coming to you. I'm curious if, for your own research, if you ever have need to go elsewhere to do the things that you want to do.
OK. I'm mostly a manager, and I've been doing that for fifteen years, so I don't do very much research myself. But, yeah, the staff does occasionally go elsewhere. The most common place they go is the Advanced Photon Source at Argonne to use x-rays which are very complementary to neutrons. So that's the most common. But we also have used the other neutron facilities, if they have special things that we don't have. For example, Oak Ridge has a big neutron facility. NIST staff will go there and do experiments. They'll go to neutron facilities in other countries for particular experiments, depending on what it is. And sometimes they have a collaborator at a university, and they'll go and work in their labs there for a week or two, to participate in making materials for their own experiments.
I want to go through some of your main research interests to get an idea of both your own work and how you've done it in the context of NIST. So first, hydrogen storage. I'm very interested. What are the biggest issues with hydrogen storage that you've worked on?
This is the last project I worked extensively on before I really got so deep in management I couldn't do it anymore. And this was metal–organic frameworks. These are the hottest materials going and have been for a long time. They're not that well known in the physics community because the applications are all chemistry. Around 2003, 2004, there was this big push for fuel cell powered cars. And the biggest problem with fuel cell powered cars is storing the hydrogen onboard.
I remember the advertisements with Arnold Schwarzenegger, with his Humvee. [laughs]
If you have an electric car, and any electric car is great, including the fuel cell cars, because the electric motor is constant torque. So the torque's really good at low speed. So the acceleration at low speed is really fun. But for fuel cell powered cars, storing the hydrogen is a big problem. You can buy a fuel cell car. No problem. But the only place with enough hydrogen stations is California.
So do you see this as an infrastructure problem? I mean, if the question is why aren't we all driving hydrogen cars now, is it an infrastructure problem? Or is it a scientific problem?
Both. The infrastructure problem is probably the more important at this point. The fuel cells work. They're done. I mean, there are basically no issues with them. The big issue, from a technological point, is hydrogen storage. Right now, fuel cell cars have gas tanks, and it really is gas, that are essentially compressed gas cylinders. They're very fancy ones, very expensive, et cetera, but that's really what they are. But what you really want to do is, put hydrogen in a material, because you can possibly make pack it more densely than you could even in a compressed gas, allowing you to store more in a given volume. So basically you would like to have a material that you could use to store hydrogen.
Unfortunately, nature conspires against us, in the sense that if I store hydrogen as an atom, usually it's bound too tightly to get it out easily. If I store it as a molecule, usually it's bound too loosely for the material to do much good. And, in fact for operation at room temperature, you need to be in a condition where you're starting to activate the bond. So the bond is actually getting longer. The hydrogen is starting to dissociate, but it can’t completely dissociate to become atomic hydrogen. So it's a really complicated, difficult problem of how do I make a material that stores hydrogen at room temperature and releases it as I want.
Is the technology there to create a fuel cell car that can go 300 miles on a fill up?
Yeah, you can buy one that goes 300 miles and then you need to fill it. Yes. That technology all exists.
So again, the question is begged, why aren't we all driving fuel cell cars?
I don't know. I think the consumer experience would be pretty good. But there's no stations. Like I said, the only stations are in California. The consumer experience is good because it's like you have when you refill your gasoline car now. You go to the station, you fill up, you take off. It's not like that with a battery car where you have to wait a while for it to recharge.
And so do you see it as a viable competitor to lithium-ion?
I think if we solve the infrastructure and, less so, the storage problem, yeah, it would be a viable competitor to lithium-ion batteries. I think it would have better consumer acceptance. If I want to drive my car across the country, I want to be able to fill it up and not wait for half an hour or forty-five minutes or an hour or whatever it takes to recharge my batteries every few hours.
And the emissions, it's truly just water? That's all that it is?
Yeah. It's really just water. But, of course, any of these devices have emissions in the manufacturing process of the devices. You need the whole lifecycle of the technology to know exactly what the emissions are. But the emission from the fuel cell itself is just water.
Now, I know your area of expertise is on the storage, but I'm curious. In terms of extracting hydrogen, where is the hydrogen coming from, and how is it stored in larger facilities before it goes into a fuel station, essentially?
Well, mostly we're still moving it around as gas, but there are lots of ways we could make hydrogen. There's catalysis, electrolysis, et cetera. They all require energy. Hydrogen is a carrier - it's not an energy source. And so you have to use energy to produce the hydrogen. For example, there are ways of doing it with solar.
So hydrogen, obviously it's a silly question, but hydrogen is not something that needs to be extracted from a source.
No. You would make it from water, almost certainly.
The more you're talking about this, the better it sounds to me.
[laughs] I think it's a viable technology. But the infrastructure is complicated, and we still really can't store it the way that would be ideal.
Now, you mentioned proteins with regard to the NIH. I'm curious about your own work in proteins and their dynamics.
Yeah. I did a bit of dynamics work on proteins, where we were trying to understand motions of proteins and what we can really see with neutrons in terms of the motions of proteins. And the reason that I think protein dynamics is really interesting is, you know, we're always trying to make structure–property relationships. And what this means for biology is you're trying to make structure–function relationships. What does this protein do? How does it do it? How do I relate that back to the structure? How does the structure control that? But it's more complicated than that. Really, the dynamics plays a big role. Because if you're going to get to an enzymatic site, the protein has to open up or whatever. So there has to be dynamics. We were really just exploring what we could see with neutrons in terms of dynamics. To be honest, we were doing pretty, I would say, simplistic experiments. They were not too difficult.
And then we hit on this idea. I had a postdoc, Amos Tsai. He now works for Johnson & Johnson. And he was much more of a biologist than I was. And he came up with this idea, maybe we should look at the stability. The reason for this was that if I have to store a protein, I have to store it in a way that I can reconstitute it. Often it's in a vial, in water or some liquid. But one of the ways that proteins are often stored, and the storage scheme of last resort for biologics, is lyophilization. Lyophilization is just a fancy word for freeze dry. So you will freeze dry your protein basically with some other things included. Salts, sugars, lots of times sugars. We all know that sugars preserve proteins, right, because they preserve foods. Salt preserves food. So there's no surprise that these are the things we use. I'd just finished building this new machine called the back-scattering spectrometer at NIST. I led the scientific program to build that instrument, and it was just coming online. We knew we could do certain measurements that gave a view of the overall dynamics of the system. We decided we'd just change whatever we were putting on the protein and then see how that affected the dynamics. Then we asked if we could correlate that with the shelf-life of a biological formulation?
And it turns out—when I started doing this, this was kind of a silly sort of thing, when you think about it. Because we were measuring dynamics on the nanosecond timescale, and we were trying to correlate with stability on the time-scale of weeks. It seems like it can't possibly work. But the postdoc was very enthusiastic. So we did it. And actually, the first thing we saw was that, yeah, the formulations that had longer shelf lives actually had slower protein dynamics on the nanosecond timescale. Then several other groups got interested in this observation and one was able to completely correlate neutron measurements of the dynamics with the shelf life of a biological formulation. Our work in this area actually led to our collaboration with Amgen that led to the CRADA for the characterization of T-VEC formulations.
Was this so specific that it only made sense for Amgen? Or is there a larger pharmaceutical…
No, a lot of biologics, the formulation is lyophilization. So this is an industry-wide problem. But that was the beginning of the NCNR interaction with Amgen.
Why the interest in carbon-based materials, specifically? What's interesting about carbon-based materials?
Well, carbon comes in lots of different allotropes. You can make Buckyball’s, which I worked on. I worked on intercalation compounds. You have graphene. You can create nanotubes. You can make diamond. I mean, just think about how carbon does all these things, and then carbon is actually the basis of life. And it is because it has very unique binding to other atoms and molecules. And so I think that I got interested in them basically because, well, this is kind of cool. I can make different materials all based on by using carbon, graphite, as a template. But then all these other new carbon-based materials came along. At some point I'll retire. If it was now, I'd probably be talking to Yury Gogotsi at Drexel and work on MXenes. I think these are the most interesting carbon-based materials going. I think that carbon does so many things it's just fascinating.
What else do you want to accomplish in your career?
One of the key aspects of NIST's success in neutrons has been the access to cold neutrons. We put liquid hydrogen up against the core of the reactor and make our neutrons cold. The neutrons that we're using are about thirty, thirty-five Kelvin right now. We also have thermal neutrons that are room temperature, but most of our instruments use cold neutrons. But we can make them colder if we switch to liquid deuterium. And so we're in the process of designing and putting in a new liquid deuterium cold source that’ll about double our cold neutron production. As part of this upgrade, we're refurbishing part of our facility, the part that we developed immediately after I first came to NIST, now over thirty years ago. I'm working on this refurbishment. And so that is the thing I'm concentrating on right now.
And why is that so important?
We're still using the same reactor as when I was a graduate student. There's no difference in the reactor, really. The cold source is better, but there's no difference in the reactor. It's really an engineering reason. We're getting the neutrons out of the nucleus. And most intense neutron sources get the neutrons out of the nucleus. So that means you're overcoming the strong force. That means there's a lot of energy involved. And so there's a lot of waste heat that you have to extract. This is a very difficult engineering challenge.
So what we really need to do is build better instruments. And this comes back to my starting on the farm and loving the machines. And so being a physicist, I like big machines. I like to build big machines, build big things. The instruments that we have built over my time at NIST are so much better than the instruments I used when I was graduate student. We can see things we could never see before. And if we refurbish these beamlines, we'll do better again. For neutron facilities, building new instruments, building new optics, all these sorts of things are the way we improve. We have to improve. We don't just build a new source, stick some instruments on. We have to really think carefully about what we want to measure, how we can best do that, and build instruments that attack that problem.
What specific advances technologically have allowed for the instrumentation to get so much better over the past three decades?
Well, there's really two things. The first is optics, particularly what we call neutron guides. Neutron guides are essentially fiber optics for neutrons. In practice these are long glass tubes that have special coatings. Over time, the coatings have gotten better. The complexity of what we can do with these optics has also improved. And so we can put a lot more neutrons on a sample than we used to. One of the instruments that we're working on, as part of this refurbishment, is a new cold triple-axis spectrometer. Triple-axis was invented in the 1950s by Bert Brockhouse, who won the Nobel Prize in physics essentially for inventing this type of instrument. Anyway, all neutron facilities that are based on steady-state sources have these. Our cold neutron triple-axis was one of the first instruments we built after in the guide hall, and it's now twenty-five years old. If I just replaced the guide, keep everything else the same, I can gain almost an order of magnitude in count rate on that instrument. So optics has been a huge, huge win. There are other parts of optics that have helped too. The way we handle neutron monochromators has been really useful as well. But really, the guide technology has been the biggest win.
And the second thing is detectors. We have multiplexed the detection schemes much more extensively than we used to. So I said I designed the back-scattering instrument at NIST. And it covers twenty percent of four pi steradians. So twenty percent of space is covered with detectors, or the equivalent. One our newest innovations is a new energy-dispersive detector that detects 54 energies instead of a single energy. And so we have a lot more detection efficiency than we used to. These also can increase your efficiency for a particular instrument by one to two orders of magnitude. So we're really talking about gains, since I started, of more than two orders of magnitude, generally, in most neutron-scattering instruments. So really big improvements.
And what—in practical, real life—what is the outcome of these gains and the improvement in the instrumentation? What can be done and what can be known better as a result of these gains?
What that means is that, you know, when you make a new material, maybe you only have a little of it. So you can measure much smaller amounts of materials than you used to be able to. We can do way more experiments than we used to. So more people can use the same facility, so we can become more cost effective. And we can put materials under conditions that we could never think of putting them in before and measure their structure in those conditions. One of the projects that we enabled with all this new technology is extreme flow. When you process materials or whatever, they're under flow. If I want to inject a biologic with a needle, it has to flow through the needle. And that could disrupt the biologic, cause aggregation or something like that. You don't want aggregation because that could induce an immune response in your patient.
And so the shear rates that we're able to do are much higher because we need much less sample. The way to get higher shear rates is to put it through a smaller and smaller tube. So right now we can put a material through a fine capillary tens of microns, a hundred microns in diameter. We can shoot the fluid through it at speeds of a hundred miles per hour, so really fast. And we can measure the structure as it does that. There's very little material in the beam. We couldn't have done this thirty years ago. If we want to look at materials under high pressures, again, you won't have very much material if you want to achieve very high pressure. So you can see those sorts of phenomena, high pressure phenomena, in ways that we just couldn't before. And that's really a lot of stuff going on in those sorts of areas enabled by better counter rates. So it has a huge range of benefits.
Dan, I'm curious, reflecting back. Obviously, it's a very clear distinction between career choices, you know, working at NIST versus being a solid-state physicist in an academic department. I'm curious, during your career at NIST, how well you've felt integrated with the broader physics community of which you are a part. Are you collaborating with academic physicists? Are you writing papers? Are you going to conferences? Are you reading the same articles? Or do you see your work, sort of, more focused within your particular work environment?
I think that we're pretty well integrated into the broader physics community. Many of the staff that work with me have been officers in the American Physical Society. So I think we're pretty well integrated. And NIST as a whole is pretty well integrated into the academic community. I tend to work on the border between physics and chemistry—lots of physicists think I'm a chemist. In fact, at my defense, David Pines said, "Dan, this is really interesting, really good work. But it was more chemistry than physics." [laughter] So I've always kind of been on the border. I'm a member of the ACS as well. And I think that we're well integrated there as well. What I see that is different in physics and chemistry is that the chemistry community is much better at integrating industrial researchers. So, I think there's a lot of room for improvement in how the physics community integrates academic research with industrial research in condensed matter physics, materials physics, what have you. I'm here at NIST, where we have lots of academic researchers and some industrial research. And I think they have a lot in common. There's difference in work environments. Projects go away quickly in industry if they decide they don't want to do that anymore. But I think there's a lot more room for interaction than we have been successful at. And I think industry is really willing to work with academia a lot more than has been the case in the physics community.
Where does NIST fit in with the overall federal infrastructure? Who does NIST report to? Who's under NIST? How does all of that work?
We are in the Department of Commerce. So you can see we have a mission to serve industry. I think it's a strength that NIST is in the Department of Commerce. Lots of academics either get funding from NSF or DOE. The Army and Navy also fund research. DARPA, et cetera. I think that this is a real strength of the U.S. system. We don't have a single Department of Science or Department of Technology. Lots of the agencies are doing research that supports the overall technological advancement of the United States, but they're doing it within their mission space. NSF is basic research. DOE is energy. I think that's a real strength. I think that we want to maintain that. I've given advice at facilities all around the world, and I think the U.S. system, in this regard, is the best. It's kind of disorganized and dysfunctional. But I think, overall the decentralization serves the U.S. well and allows us to efficiently advancing on a broad scientific front.
If you could reflect back on the budgetary environment at NIST, from when you started to today, are these good years? Has it been stable? Has it been up and down?
I came to NIST when the reactor had gotten additional funding to build a guide hall with seven neutron guides and a bunch of instruments. I was really excited to be part of that. And then in 2007, as part of the America Competes Initiative, we got money to essentially double the size of our facility. Since then our funding has been relatively stable. No ups and downs, really. So generally we've had enough money to be successful, but we've not had as much as we could have usefully spent.
But in terms of, you know, working in an environment that really is all about basic science, you've had what you've needed to accomplish your mission?
Yeah, I think you would say we've had what we've needed to accomplish our mission.
So, Dan, I think for my last question I love, especially when I'm talking to people in government, kind of, positions. To the extent that this would serve as something that a graduate student who's thinking about a career and might be poking around and come across your work, to what extent do you see NIST as a really wonderful place for people who are thinking about a career in science, a career in physics, not necessarily in an academic or even a commercial environment?
I think NIST is great. I've loved working at NIST. It's extremely collegial. It's intellectually very stimulating. We have graduate students all the time because they're coming from universities doing work. We have some resident graduate students, et cetera. I think they mostly find their experience to be quite good. Some go to academia. Some stay. Some go to other government labs. Some go to industry. Being a user facility, there's the saying "no one ever really leaves" because they come back. Their students come back; their postdocs come back. And so I think that if you're a student, going to a facility is a good move. I think you can have a great career. You're not going to have an army of ten graduate students or something like that. But you probably can get a postdoc or two and pursue your own ideas. And you have this technology, at least at our facility, that isn't common, and so people want to collaborate with you. And so, it's easy to interact with a very broad scientific community.
There's a perception of scientists as being a little, shall we say, introverted. I think that in general, scientists at user facilities are more extroverted than the average physicist, because our job is to go out and interact with the community. And so I think that if you want to interact with lots of different scientific projects and lots of different people while having the opportunity to really do good research of your own, I think you would enjoy working at a user facility.
Well, Dan, it's been phenomenal talking with you. This is a very unique and important view into how physics is done at NIST. And I want to thank you for the time you spent with.
I'm only a very small part of NIST. My colleagues in other parts of NIST, don't necessarily think we're exactly the same as they are.
Of course. Of course. All right. Well, Dan, again, thank you so much.