Katherine Harkay

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ORAL HISTORIES
Katherine Harkay

Credit: Katherine Harkay

Interviewed by
David Zierler
Interview date
Location
Video conference
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Interview of Katherine Harkay by David Zierler on May 17, 2021
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
www.aip.org/history-programs/niels-bohr-library/oral-histories/46818

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Interview with Katherine Harkay, Senior Scientist at the Advanced Proton Source (APS) at Argonne National Laboratory. Harkay describes the APS upgrade and how the APS informs her broader views about the interplay of theory and experiment in accelerator physics. She recounts her childhood in New York City, the import of her Hungarian heritage, and her early interests in science. Harkay describes her undergraduate work at St. John’s and her attractions to experimental physics before entering the PhD program at Purdue. She describes her work at Fermilab and the opportunities that led to her work with Yanglai Cho at Argonne and the origins of the APS.  Harkay explains the broad range of experiments done at the APS and she describes the investigation of high-intensity limits and the safety considerations that ensure its proper operation. She discusses her work on cathode research and development and she explains the administrative responsibilities she took on after being named accelerator physics group leader. Harkay surveys Argonne’s efforts to bring more women into leadership positions and the broader value of a diversity of perspectives in science. At the end of the interview, Harkay emphasizes the importance of public outreach, and she cites the value of the APS’s value in X-ray imaging of the SARS-CoV-2 protein to exemplify the point.

Transcript

Zierler:

This is David Zierler, oral historian for the American Institute of Physics. It is May 17, 2021, and I’m delighted to be here with Dr. Katherine C. Harkay. Kathy, it’s great to see you. Thank you for joining me today.

Harkay:

Yeah, it’s great to talk to you today.

Zierler:

Kathy, to start, would you please tell me your title and institutional affiliation?

Harkay:

My title is senior physicist. I’m at Argonne National Laboratory at the Advanced Photon Source.

Zierler:

What does the title Senior Physicist connote, to the extent that national laboratories have something similar to a professor position in an academic environment?

Harkay:

Right. So the senior scientist level is equivalent to full professor. It involves an internal nomination by someone, and it goes before a committee that reviews the case and then makes a proposal for the promotion to the management.

Zierler:

Kathy, what affiliations currently, or over the course of your career, have you had with Chicago? Because I know there’s many strong ties between the University of Chicago and Argonne Lab.

Harkay:

I don’t have any direct affiliation with the University of Chicago. I do have other colleagues who have joint professorships with the University of Chicago. There are several colleagues of mine who have joint professorships with other local universities. I have an affiliation with Purdue University Department of Physics and Astronomy. I’m an Associate Staff Member. It’s a non-paid appointment that does allow me to have students and to be on their dissertation committee.

Zierler:

Now, did those students — would their research have an obvious connection with Argonne, or not necessarily?

Harkay:

Yes, they would. So, students that we would mentor would get involved in some kind of research that’s directly related to Argonne’s work.

Zierler:

Kathy, just a snapshot in time right now: what are you working on? What’s interesting in the field more broadly?

Harkay:

Well, probably the most exciting thing — well, the most exciting thing is the upgrade of the Advanced Photon Source synchrotron. What I’d like to say is, I came in to Argonne at the tail end of the first and existing Advanced Photon Source, but I came in — it was already designed, and they were doing the installation, and I got involved in the commissioning. This one, for the upgrade, I’m involved from the beginning, and I’ll be involved through the end. It’s not common in a physicist’s career that you would get involved in a major machine upgrade from the beginning to the end, and it’s almost like I’m involved in two of them. So, it’s actually very exciting, because you — it’s a quite extended effort to do the design, the physics design, and then there’s an engineering design. And then to see it come to fruition is really thrilling. So, I’m really looking forward to the various ideas that me and my colleagues have developed and see that they work. So, that’s quite exciting, and it’s taking up all my time. [laugh]

Zierler:

Kathy, a question we’re all dealing with right now: how has your science been affected, one way or another, by the pandemic — by remote work, by not being able to go into the lab as much as you can, not being able to see your collaborators in person?

Harkay:

Yeah. So, it’s quite fascinating to me. I’ve been into the lab about eight times in the last year. All of the work that I had been doing, I’m doing remotely on the computer, and it involves some very complicated things. We regularly do experiments on the accelerator. I mean, we typically sit side-by-side in the control room. You would have the control room operators behind us, looking at — monitoring critical systems and alarms, and me and maybe another colleague physicist would sit side-by-side, and we would work together on the experiment. Now, the physicists each sit at home, in front of their computer. We have our screens up. We have a Zoom or a BlueJeans link over here. So, we have the audiovisual with the control room. We have the audiovisual with each other. We share our screens. It’s almost like being transported into the control room next to your colleague, and we’re able to do all the functions. We’re able to run the accelerator, run the experiment, completely from home. It’s really out of this world. I mean, it’s [laugh] a really amazing thing, what technology has been able to enable, that I don’t think anyone fully-appreciated the power of that technology [laugh] in this regard.

Zierler:

So, you really haven’t missed a beat, it sounds like.

Harkay:

I have not missed a beat. We are installing equipment, and there are many engineers and technicians that are on site most of the time to take deliveries, do the acceptance, do a checkout, and then the times that I’m going to be in is overseeing that installation. So, there’s clearly a need for people to be on site. But it’s been an as-needed basis.

Zierler:

Given your productivity, Kathy, I wonder what that might portend more institutionally at Argonne about their response to in-person work post-Covid. What are people saying?

Harkay:

Yeah, this is an active discussion right now, and different people have different opinions. Some people want to go back to the five-day week. Other people want some hybrid models: some days home, some days not. I wouldn’t mind [laugh] being mostly working from home. Some of the things that don’t work well — communication is especially challenging in this remote work. You know, how to get ahold of your colleague. You know? We have Teams. It’s almost like, you don’t have their phone number, but you can call [laugh] them on Teams, and they show up, and you can talk to them. But getting small decisions – in the past, I would just go in their office: “Hey, what’s — how big is this thing?” And then they would give you the number. But now, it’s: “Oh, when do you have time?” Do a schedule. It just becomes more complicated. Sometimes small decisions just take much, much longer to take care of. And you don’t have all the people at the same time, in the same room. So, it can be very challenging. I feel like I’m managing that pretty well, but that part is time-consuming. [laugh] So, I think for the future, I think there are many benefits for working from home. You know, all the time saved from commuting. The laboratories are certainly getting [laugh] their work done, so I think most people would be happy with some kind of major change, which would involve a lot more working from home, working remotely.

Zierler:

Kathy, given your tenure with the Advanced Photon Source, I can’t help but ask some really big broad questions at the outset of our conversation, which I think will punctuate a lot of the more specific questions. So first, over the course of your time with the Advanced Photon Source, obviously as in all of physics, there’s an interplay between theory and experiment. With specific regard to the APS, when has theory been out in front and has provided guidance to the experiment? And when has experiment been out in the lead and provided guidance to the theorists?

Harkay:

I’m going to be speaking primarily about the accelerator physics part, because the Advanced Photon Source is X-ray science as well, and I don’t have a good feeling for the answer to your question on that. But for the Advanced Photon Source upgrade in particular, I would say that theory has been driving the design, because there have been many advances in — well, okay. [laugh] There’s a very strong interplay. It’s very hard to say, chicken and egg: which comes first? Because the reason that we’re able to build the Advanced Photon Source upgrade now is because in the past 20, 25 years, there have been advances in technology, specifically in building magnets. We were not able to build the magnets that we are building for the upgrade today. At the same time, there’s some very detailed beam dynamics theory that had to be understood in order to achieve the design that we have. And a lot of that involved numerical simulation. We have computer resources today that we didn’t have 25 years ago that are able to carry out these massive parallel computer simulations that you need to design to the degree that we need for this upgrade. So, it’s very much an interplay. I would say for now, for the design that we’re doing now, there’s a very strong relationship between physicists and engineers that we didn’t have in the past. In the past, the physicists would do the theory, design the machine, hand it over to the engineers, and the engineers would make the drawings and then build it. Now, it’s like a puzzle. There’s so many — it’s a very extreme design and very small tolerances and all these different dimensions. So, you try to optimize the machine. You try to optimize this parameter, and then that parameter is affected. So then you try to equalize those things, and all of those decisions involve engineering design and engineering solutions. So, we’re really working hand-in-hand with what’s possible to build. You’re pushing [laugh] the technology. You’re pushing the machine design to optimize, to come up with an optimized design.

Zierler:

Kathy, a question even more fundamental than that: in light of the significance of the upgrade, what were the major research questions in the field that prompted the creation of the Advanced Photon Source to begin with, and are those same research questions applicable today?

Harkay:

The questions that led to the development of the upgrade are fundamental science questions. In materials discovery — all the things — all the reasons why we built the synchrotron light source. So it has — there are several reports that the Department of Energy put out with input from the community on what is needed, so it’s all these — you know, materials under extreme conditions, like very high pressure — the types of conditions that you have, for example, in the center of the Earth. So, materials under high pressure — these conditions are reproduced at the sample that we irradiate with X-rays to try to understand how materials behave under these extreme conditions. So, that’s something that the upgrade in particular is suitable for, because the probe that we’re building — the probe, which is the X-ray beam — is much, much higher brightness. It’s more photons in a smaller phase space. So, you’re able to image and probe materials on a much, much smaller scale, so like nano-scale dynamics, dynamics of materials in vivo. So you know, previously, in synchrotrons today, you would take proteins of different systems — viruses, bacteria, human proteins, other kind of proteins. You would crystallize them in some solid form. You’d put the crystal in the X-ray beam, and then you would measure the — make a map of the molecule, the molecular structure. Well, that’s not how proteins actually exist in the world. They exist in biological systems, basically in water. [laugh] So, how do you reproduce that? Well, to do that, you need very, very small crystals and have them in liquid. Right? So, with the upgrade, we would be able to image systems like that, because now that tiny probe can image very small nanoscale proteins within a medium. So, you’re getting closer and closer to mapping and imaging real systems in real time in extreme conditions. And this is what’s driving the need for these new sources.

Zierler:

If I can attempt an even more basic question than that: how does the APS work? And if I asked you this in 1995, how different would your answer be?

Harkay:

The APS works as — it’s basically the same now [laugh] than in 1995. So, this is something that I think is pretty, like, wow. And it’s a behavior that we take advantage of, and it’s like no big deal. But it’s really actually quite amazing, I think. If you take — an electron is a negatively charged particle. Right? It normally exists inside atoms, atoms inside molecules, inside something else: solid, liquid, air. But we can take these electrons and separate them out and have them flow. It’s not completely different from electrons in a wire. In a copper wire, electrons are flowing, and they create electricity, and there’s amazing things that we can do with electricity. Now we have these electrons, and we have them sit in a tube. We pump the air out. The electrons are flowing, and it’s just like a current. You can think of it as a current. Now, electrons — charged particles — any charged particles — has this really amazing property that — when you accelerate them. And not — well, going faster in a straight line, but acceleration also means changing its direction. So, we put a magnetic field. The electrons will go, and the magnetic field will bend them. Anytime you have a charged particle that is accelerated, which in our case is bending, there’s a chance — there’s a quantum mechanical property that that electron could convert some of its energy into a wave. So, it slows down a little bit. A little bit of its velocity slows down a little bit, and then it converts some of its energy into a wave, and that wave in our case is an X-ray. And then we just give the energy back. You know, we give the electron — we give it another kick. So, this property that the electron can convert — that we can actually do this. We can convert electrons’ energy into a wave, and that wave becomes an X-ray, and that X-ray is used for the science. It’s actually a phenomenal property. Anyway, sorry. [laugh]

Zierler:

That’s great. That’s great.

Harkay:

I’m not very articulate.

Zierler:

No, no. That’s great.

Harkay:

That’s what I’m trying to say. [laugh]

Zierler:

Kathy, let’s do an administrative question. This is probably something that both precedes your time and was above your pay grade, but what is your sense of why the Advanced Photon Source is sited at Argonne, as opposed to another national lab?

Harkay:

Well, there’s always — whenever there’s a concept for a new scientific facility, there’s almost always a competition. So, the best minds at several laboratories, usually, make a proposal to the Department of Energy for a new facility. And then, the decision is based on a number of things. Part of it’s technology. Some of it’s the science, the best proposals. Sometimes, it’s a function of region, making sure that different regions have different facilities. Sometimes, it’s a function of the laboratory portfolios. So at the time that the — I mean, I can’t comment [laugh] — I was at the very beginning of my career when the APS was first developed and sited at Argonne, but I know that there was competition at the time, and Argonne won that competition, and then it was built at Argonne. An upgrade to the APS is obviously at Argonne, because we’re reusing a lot of the parts that we have already. So, that becomes — yeah, it becomes logical that we would site it at Argonne. Instead of a synchrotron, if we were to build an entirely different facility, like a free electron laser, then you would have our proposal, another lab would have its proposal, and then there would be a review process.

Zierler:

And in what way is best-case scenario would successful experiments at the APS contribute, possibly, to physics beyond the standard model?

Harkay:

So, the work that we do does not involve the standard physics model, because we are not doing particle physics at Argonne, at the Advanced Photon Source. We have a high energy physics division that develops detectors and collaborates with scientists at CERN and Fermilab on high energy physics. But the work that we did at Advanced Photon Source does not involve high energy physics or the standard model.

Zierler:

Is there any applied science portion of APS, or do you operate essentially in a pure basic research environment?

Harkay:

Yeah. So, the APS does basic and applied science on the X-ray side. So, it’s basically two things. You know, we have accelerator science, and we have X-ray science. So, there’s been a lot of development on the accelerator side. I would say that’s applied. The accelerator development has been applied. Yeah.

Zierler:

Well, Kathy, let’s take it all the way back to the beginning. Let’s start first with your parents. Tell me a little bit about them and where they’re from.

Harkay:

That’s a big segue. [laugh] Yeah, I was hoping you’d ask me this question. So both my parents are immigrants. They were both born in Hungary. During World War II, they left Hungary. They became refugees. They lived in Germany for five years, and then in 1950 is when the U.S. opened its doors to — at the time, they were called “displaced persons,” DP. Now, my parents did not know each other during that period. So, they came out with their parents, and in my mother’s case, her siblings, and they ended up in New York, and they met in New York. They met at the Hungarian church, in the choir, and they got married, and then they raised their family. So, I am one of four siblings, and we were all born and raised in New York. We were very heavily connected to the Hungarian community. In New York, I went to weekend Hungarian school. I’m bilingual. I’ve been involved in Hungarian community girl scouts — you know, Hungarian scouts. And so, I brought that with me throughout my whole career. I live in Chicago now, and I’m very heavily involved in the Hungarian community there. So, I definitely — I call myself Hungarian-American. It’s a big part of my life.

Zierler:

To go back to post-war Hungary: what kind of refugees were your parents? Were they political refugees? Religious refugees?

Harkay:

I would say “political,” because both my grandfathers were members of the Hungarian army. Hungary, at the time, was allied with Germany, and they fled when the Russian troops invaded Hungary. So, they were fearful that they and their families would be killed. So, I would call that political.

Zierler:

Where in New York did you grow up?

Harkay:

Queens, New York City.

Zierler:

Where in Queens?

Harkay:

[laugh] Jamaica Estates.

Zierler:

What were your parents’ professions?

Harkay:

My father went to law school and wrote a dissertation on the war in Europe. A professor on his committee wanted him to change a fact in his thesis, but my father wouldn’t. So he walked away from a law degree. My father’s career was in the telephone company. So, he started out as a — okay, so you have to remember that the two families came — they had nothing. They basically came to the U.S. — they had nothing. So, my father started out as a linesman, you know, going up telephone poles and whatever they do. And then he worked his way up in the telephone company and became a marketing manager — marketing research manager. And then he retired. So, he made a very successful career supporting his family. My mother —

Zierler:

Did your mother work outside the home?

Harkay:

Yeah. My mother got a bachelor’s of fine arts, and then she ended up a stay-at-home mom raising us.

Zierler:

What kind of schools did you go to growing up?

Harkay:

What do you mean?

Zierler:

Public, private, large, small?

Harkay:

Oh, okay. Yeah. [laugh] Okay, yeah. So, I went to Catholic private schools my whole education through undergraduate. So, from elementary, high school, and then university. That was all in New York.

Zierler:

Were they co-ed, or all girls?

Harkay:

The high school was all girls; otherwise, co-ed.

Zierler:

When did you start to get interested in science?

Harkay:

Yeah. So, that’s an interesting question. I’m sort of an introvert. I remember as a child growing up, you know, soaking up the National Geographic magazine, watching the nature shows on TV. My father is sort of a handyman around the house. He had a workshop downstairs. I was constantly down there with him, helping him build stuff. And then when I was 12, 13 years old, I asked my father: “What do you think I should do?” [laugh] He said: “Well, you really love math, and you’re good with your hands. I think you’ll like physics.” And that’s when I made the decision: “I’m going to be a physicist.” You know, looking back, I had [laugh] no idea what that meant, but to me, it was — you know, that’s hard to do. I’m going to do it. [laugh] You know? Everyone says that that’s hard to do. I’m going to just do it. I’m just going to be a physicist, and nothing is going to stop me. [laugh] And that’s what I did.

Zierler:

Did you have any idea growing up the rich history of physics coming out of Hungary?

Harkay:

Well, it was probably a little bit later when I understood that, but absolutely, I’m very proud of how many prominent scientists, physicists in particular — mathematicians, scientists, chemists, biologists, come from Hungary. It’s a small country.

Zierler:

Yeah.

Harkay:

It’s only about 15 million Hungarian speakers in the world. And there’s a tremendous — there’s this very strong science, physics — I actually met Eugene Wigner, and I met Edward Teller in person. And it was a thrill. I can’t say that I went up to them and told [laugh] — you know, talked to them and told them about my life. No. Didn’t quite happen like that. But I was like, amazed that — oh, wow. You know? [laugh] If they only knew, you know, that I’m also Hungarian. Yeah. It’s exciting.

Zierler:

Did you have a good curriculum in math and science in high school, would you say?

Harkay:

I would say that — okay. I did not base my career based on being inspired in high school. I think — you know, I did go to — it was a college preparatory high school, and I would say that being an all-girl high school made a big difference in my success, because there are studies that show that girls that go to all-girl high schools tend to get encouraged to go into science. And so, I would say that did play a big role, but it’s not the science classes. I would say it’s — in particular, I would say that the entire curriculum in high school and the support that I got from my various teachers and professors to exceed and push myself academically — I would say that it was at the undergraduate level where — it was a relatively small physics department in my undergraduate. Again, it was that connection with my professors that really made my career possible, because I got encouragement and support, one-on-one relationships with them that I would not have gotten, had I gone to a huge university. And in my particular case, that made a huge difference. It was the time that I landed at Purdue University for my graduate work is when it really hit me. [laugh] Like, “Whoa.” You know? “This is deep.” I really have to work to basically get up to the level of some of the bigger schools, let’s say. But I’ve always worked much better under pressure, so that pressure just, you know, lights a fire under me. [laugh] And I’m not going to let anything stop me. So it’s interesting. Yeah, I guess — I think it’s that one-on-one relationship and nurturing environment. Maybe because I’m a woman in science, and I didn’t have that negative — you know, “you can’t do it” kind of thing going through my education. I had a lot of support, and it made a huge difference. That, plus my parents’ support. Neither was a scientist, but they supported my dream.

Zierler:

Between your grades, financial considerations, geographic considerations, what kind of schools did you apply to for undergraduate?

Harkay:

For undergraduate, I didn’t even — [laugh] I just went to the same school. It’s in the neighborhood, walking distance. It’s the school my siblings went to. It’s the school were my father got his degree. It wasn’t a question. I just went there.

Zierler:

Which school is that?

Harkay:

This is St. John’s University.

Zierler:

Ah. Did you major in physics?

Harkay:

I majored in physics. Yeah. There were six majors, and we went through every class together, from second year on. It was great.

Zierler:

Was the plan physics right from the beginning? Did you declare right away?

Harkay:

Yes. Yes, I did. I knew what I wanted.

Zierler:

To what extent did you have exposure to the binary in physics education, between preparing for a career in experimentation and one in theory?

Harkay:

Could you repeat that? I’m not sure what you mean.

Zierler:

As an undergraduate, did you take the kinds of classes…

Harkay:

Oh, as an undergrad.

Zierler:

…that steered you in one direction or another?

Harkay:

I certainly didn’t know that I would end up doing accelerator physics at that point. I’m trying to — I certainly enjoyed the laboratory courses more. And so, I would say I was leaning towards experimental physics at that point. Yeah.

Zierler:

Did you have any summer internships that were relevant to your physics education?

Harkay:

No. No, I didn’t. And I sometimes think that might have been because I applied, and I didn’t come from a big school. You know? I didn’t have connections. [laugh] I didn’t come from a big school. I don’t know. I sometimes bemoan that, but you know, how come I didn’t have that opportunity to do a summer internship in physics and science. But you know, in the end, it didn’t affect my career, I would say. I mean, I have had summer undergraduate students work with me, and it’s a joy to work with them. I know that it’s a tremendous opportunity for them. I did not have that opportunity. I think that’s my guess, that it’s because I didn’t have that school name behind me.

Zierler:

Do you have a specific memory when you realized you wanted to pursue physics for graduate school and even as a career?

Harkay:

Yeah. So, I went directly from undergraduate to graduate school, because I loved physics, and I knew that if I wanted to do anything related to physics, I would need a graduate degree. I probably had conversations with mentors to ask them about that, and I remember them saying: “A Ph.D. is your calling card. You know, if you want to do research, you have to get a Ph.D.” And so, I did want to do research, so I went on that path. Now, after two years, after I got — at the level of my master’s, I decided to stop and take a break, because what happened was, I didn’t see a specialty that really grabbed me at the time. And rather than let that decision — rather than stay at Purdue and try to make a decision, I decided to work and see what [laugh] — what I was interested in is, what areas of physics are going to lead to a good job? So, I was very pragmatic that I wanted the opportunity for a good job, and not just do physics for physics’ sake.

Zierler:

Did you talk to professors? Were you looking at the H index? How did you make these determinations for where a fruitful career might take you?

Harkay:

Well, what I did is, I looked for a job, and I found a job in a think tank. So, a think tank is a smaller company. You consult for others, and you don’t build anything, but you have access to a lot of research. So, I ended up taking a job. Actually, I was deciding between going to Corning glass works versus a small company in Washington, DC I ended up going to the company in DC that’s a think tank — a not-for-profit think tank. And that’s where I developed my interests and ultimately went into accelerator physics. So, there’s two parts: one is this company was doing — this is in the ’80s — and they were doing work on Ronald Reagan’s Strategic Defense Initiative, SDI, the “Star Wars.” Right? So, people were talking about building accelerators and launching them into space. [laugh] Okay? So, this is where I learned about accelerators and got a sense of the breadth of accelerators. The other thing that happened is one of my professors at Purdue — he’s a high-energy physicist — he had been keeping track of me the whole time, and he was trying to convince me to do high-energy physics. I decided high-energy physics was not for me. And then he said: “Well, how about accelerator physics?” He knew of a program at Fermilab where I could go and do my degree in accelerator physics. So, it was the right combination of — I saw a future in accelerators based on what I saw people were building in the world and their applications of accelerators, and then my professor showed me the road, showed me a route, to how I could go ahead and pursue a Ph.D. in accelerator physics. So, that’s what I ended up doing. I stopped working. I went to full-time student mode again. I moved to Chicago, and I basically worked at Fermilab with scientists there, and I did my research and got my degree.

Zierler:

What was your project at Fermilab?

Harkay:

At Fermilab, there are a number of different accelerators. One of them is one of the injectors into the main collider. It’s called a booster. It’s a common name. [laugh] You know, boosting the energy from low energy to high energy. So, my project was to try to overcome a limitation in that booster that was a longstanding limitation, and it was — we ended up doing — I worked — it was an experimental project with a little bit of theory to overcome — it’s one of these things called intensity limits. So, almost all accelerators, as they evolve, you try to increase their performance, and one way to increase their performance is to try to push more particles through there. The booster is a proton accelerator, so you try to increase the protons. That means increasing the intensity or the current, and there are many reasons why, ultimately, there’s a limit to how much you can do. So, it involves understanding electromagnetism, understanding the interaction of the particle beam with the vacuum system that it’s in, the vacuum chamber it’s in, and so I was working on a particular component where something called wake fields developed. So, it’s the same component that gives the protons energy. It’s called the radio frequency cavity — accelerator cavity. So, the cavity has an electric field that gives energy to the protons, but the proton beam itself has energy. It has a field, and basically, the electric field of the beam can fill that cavity with energy. And that energy gets left behind when the proton beam passes through. On the next pass — it’s a circular machine — the next pass, it comes back, and that energy could still ring. It can still stay there, so it’s called — it’s a wake field. So, these wake fields — it’s a little bit like if you have a boat. The boats going through the river — it leaves waves. Right? We often use the same term. We call that the wake. So, the wake, then, is like a wave. Right? The wave comes, it hits the shore, bounces back, and the boat coming after that can be affected. So, it’s a very similar — electromagnetically, the beam produces wakes, wake fields, and those wake fields can persist and affect the beam that’s coming behind it. And by ‘affect,’ I mean it could shake the beam, and then it can throw the protons out of the machine. So, I was working on a way to minimize that wake field, to damp it, basically — damp the wake field, so that it would overcome that particular limit.

Zierler:

Kathy, was the plan always to return to Purdue, or you were open about where you might finish your graduate work after Fermilab?

Harkay:

Well, the easiest path was to go back to Purdue, [laugh] because I didn’t have to retake the qualifier. That was probably the biggest [laugh] reason. Again, I’m practical. So, I asked them: “Well, if I come back, reapply, do I have to take the qualifier?” [laugh] And plus, they were very open to this arrangement with Fermilab, where I would be offsite doing my experiment at Fermilab, and plus I had a professor — my high-energy physics professor was my advisor. He was very happy to take me on as a student. So, it was a win-win situation. It was funny. When I went back, they still liked me. They still know me. Oh, yeah. They were so excited. They went to the drawer. They found my old photograph. [laugh] They put that back on the wall. You know, I had a good relationship with the department already, and so, it was really the best. There was really no decision to be made.

Zierler:

And your advisor was Laszlo Gutay.

Harkay:

Yes, that’s right.

Zierler:

How did Laszlo come to be your advisor?

Harkay:

He’s Hungarian.

Zierler:

Perfect.

Harkay:

[laugh] And he actually met me way before I started at Purdue, because I was a debutante at a Hungarian ball in Washington, DC, age 16 or 18, and he was there. And my father introduced me to him, and we talked, and he learned that I was interested in physics. And so, he had [laugh] eyes on me from before I even really appreciated it. Yeah. So when I started at Purdue, he was already mentoring me from that point on. And I still see him and talk to him on a regular basis, even after he retired.

Zierler:

What was Laszlo’s research? What was he known for?

Harkay:

His career was in high-energy physics. He was involved in research at CERN, and he was part of a team that discovered the quark, and he also played a big role in discovering gluons. So, he built detectors, and he did experimental work for these discoveries.

Zierler:

What was the intellectual process for you, developing your dissertation?

Harkay:

For my dissertation, I relied on my advisors at Fermilab to select appropriate projects. Fermilab had a Ph.D. program in accelerator physics, so they had a number of physicists who — I was one of the first — early students in this program, and it’s still going on. They take on about 10 graduate students in any given year. And so, I relied on them. My first advisor was a physicist, Vinod Bharadwaj. He was the head of the booster. And so, he’s the one that identified this issue, this intensity limit in the booster. I got started on that project. About midway, another physicist from Princeton University — his name is Patrick Colestock — came to Fermilab. His background is in plasma physics. And he took an interest in my project, and he ultimately became my ultimate advisor. What was great about working with Pat Colestock is he’s a theorist and experimentalist, very rare among physicists, with almost equal ability in both. It turns out that plasma physics has a lot of overlap with these intensity limits in particle beams, and before that, you had high-energy physicists doing accelerator physics. But it turns out that I think the physics of this intensity — these intense limits and wake fields is much more related to plasma physics, the kind of — the mathematics and the theory that relates to instabilities in plasmas. So, I gained tremendous — it was a tremendous input to work with Patrick, because it really boosted my understanding of the physics, and I think it ultimately made a much more complete project and piece of work.

Zierler:

Anything memorable from your oral defense?

Harkay:

[laugh] The oral defense was at Purdue. Laszlo Gutay was there, and they invited Pat Colestock to come. And I mean, the defense itself was — okay. I was up all night, whatever, and then drove down. That’s one thing. I mean, I felt prepared. But I think in the end, it was Laszlo and Pat that convinced the committee, or told the committee, you know, the context of my work. And they both loved my work, so I really — yeah. I didn’t get — I wasn’t shot down during the defense, like I hear happens to some people. The committee was very happy with the work, and they understood the context based on the expertise of, you know, my professor, colleague, and the expertise from Fermilab.

Zierler:

Besides Argonne, where else were you looking for postdoc opportunities?

Harkay:

That’s an interesting story as well. I finished my Ph.D. in ’93. ’93, I think, is the same year that the SSC was cancelled. So here I was, a fresh Ph.D., and I’m like: oh, no. The streets are going to be filled with accelerator physicists looking for jobs. So I was like, oh, what am I going to do? [laugh] So, I talked to my officemate, who was Carol Johnstone, at Fermilab. Senior to me. She was a scientist, and she said: “Go talk to Yanglai Cho at Argonne. I think he might be looking for someone just like you.” Like, “Okay.” [laugh] So, I took my CV, and I don’t know — she introduced me to him. I don’t know. It was some kind of luncheon. And I told him what I was working on, and it just so happened that he was looking for a physicist that could help him with intensity dependent limits for a design he was working on for a spallation neutron source called — so he said, “Come.” [laugh] So, that’s how it happened. I wanted to stay in the Chicago area, and so this just happened, and it happened pretty quickly. So, Yanglai Cho hired me at Argonne at APS, and I just went right into this project. Yeah. That’s how it happened.

Zierler:

And was that a staff position right away, or that was a postdoc?

Harkay:

It was a staff position, temporary. It was a temporary staff position. So, I ended up being a temporary for two years, and then I became a full-time employee.

Zierler:

And what was the initial project? What were you working on at first?

Harkay:

Yanglai Cho originally led and built Advanced Photon Source. And so, it was already in the — past construction, in the commissioning phase, and then he was on to designing the next machine he was interested in. And that is called a spallation neutron source. So, spallation neutron source takes a very high-intensity proton beam, collides it with some material to make a neutron beam, and then the neutrons are used for research. So, the spallation is the process in which the protons are converted to neutrons in the target. So, he was designing a spallation neutron source that would be sited at Argonne. So, that was his project. It was a design project, and that’s what he hired me to do. And I was doing the part where — you know, how does the design need to look so that you can overcome the intensity limit, because he’s trying to build a more powerful spallation neutron source than what was built before.

Zierler:

Kathy, how much of your graduate training was directly relevant to this, and how much were you simply learning on the fly, figuring out things as you went along?

Harkay:

The graduate education was all the basics. You know? The quantum mechanics, the E&M mechanics. It’s basically the foundation. Everything else I learned on the job.

Zierler:

What were some of the major technical challenges, initially?

Harkay:

Where? In which one? In Argonne?

Zierler:

Yeah, at Argonne. Your initial work.

Harkay:

Initial technical challenges — so, my work was all design work, so it was using computers. I had to learn how to use various computer modeling software. I don’t know. Yeah, I’m not sure. This part’s going to be edited out. [laugh] Technical — okay, so technical challenges. So, I was working in a smaller part of Argonne, because it was just the design team for this spallation neutron source. Being an experimentalist, I was more interested in hands-on, so I was also taking shifts, commissioning the APS, the Advanced Proton Source, and I loved it. I loved it. Sitting in the control room and getting the beam to work, getting the accelerator to work. So, I had my eyes [laugh] on the APS, and at some point, the spallation neutron source proposal was not accepted to be built at Argonne. So then, what should I do? So, I went and I asked the head of the APS: can I join the APS instead? And so, that’s —

Zierler:

And who was that? Who was head of APS at that point?

Harkay:

That was John Galayda. John Galayda was head at APS, and then he ended up going to SLAC at some point. Yeah. But he made that happen for me, that I could switch over to APS.

Zierler:

And this would have been what, the first year before the light turned on? ’94?

Harkay:

No, no. I switched over around, I guess I’d say 1995. I was involved in the commissioning of the APS, so that’s — you know, first light, I was involved in that, but not in an official capacity, because I was still working on the spallation neutron source. But I was involved in the control room and experiments pretty much from those first, those early days. I think ’95 is probably the official start of X-ray user operation. Yeah.

Zierler:

I’m curious about the nomenclature: “first light,” which connotes a certain drama, where there’s no light, and then there’s light. Is it really that much of a binary?

Harkay:

So much of these things is — you know, it might be there, but you’re not looking. So, “first light,” I think, was when there was the first diagnostic that was actually imaging that synchrotron light, because the synchrotron light would have been there, but maybe not imaged. So I think the first light was when the photons — some diagnostic was placed in a way that it could detect those photons. Yeah.

Zierler:

Given that you were there right from the beginning, what was the appreciation for how singular the APS would be as a research tool? In other words, was it the kind of service that was available nowhere else on the planet, or in what ways was it complementary to other experiments?

Harkay:

So, it was not one of a kind, but the APS was only one of three high-energy synchrotrons. So, by high-energy, this is photon energies above 100 KeV or so. That’s because the APS was built on 7 GeV electrons. It was a facility in France at Grenoble called ESRF, and that was built two years prior to us, and that’s 6 GeV, and then the Japanese built SPring-8, which is 8 GeV. So, the APS became one of three big high-energy X-ray synchrotrons in the world.

Zierler:

When did you first meet Richard Rosenberg?

Harkay:

Richard Rosenberg! So, John Galayda was the one that connected me with Richard Rosenberg, because Richard Rosenberg is a surface scientist, a chemist, an experimental scientist with deep knowledge of something called secondary electrons, which is when you have some surface — electrons hit the surface, and the secondary electrons are emitted — okay. Photoelectric effect — you know, so Einstein got the Nobel Prize for photoelectric effect. There’s photoelectric effect, but then there’s also secondary [laugh] electron emission. Different phenomena that occur. Richard is also a photoemission spectroscopy expert. And so, John Galayda got me connected with Richard to work on something called electron cloud effect. Now, why did John Galayda do this? It’s because this was a phenomenon that was starting to become a concern at other accelerators. One of them was at CERN. And it was also discovered at SLAC in the B-Factory. I’ll explain what these are in just a moment. But it was an effect that they observed, and people asked us: well, you should observe this at the APS. How come you don’t observe it at the APS? So, it was one of these questions that was particularly interesting to me when something — theorists say that something should be happening and we don’t see it. So, that’s when I get interested, because I like to prove [laugh] the theorists wrong. So, I got interested in this project. Clearly, there has to be a reason. Right? So, I brought my accelerator physics skills in together with Richard’s understanding of surface science, and we came up with an experimental program to measure the electron cloud effect in the APS. And that led to [laugh] — you know, it led to basically everyone adopting the diagnostic that Richard developed for this — to measure this electron cloud effect. Now, what is the electron cloud effect? What it is — you know, you have the vacuum chamber. It’s made of some stainless steel, aluminum, typically. And you have the particle beam going through. Now, if some — let’s say you have an electron beam. If some of the electrons on the fringes deviate from the center, they can deviate and hit the wall. This is called a beam loss. It happens all the time. Now, an electron hits the aluminum chamber, there’s a chance that it will hit — it could pass through. But it may also produce secondary electrons. It depends on how much energy it has when it hits the wall. So, if you have secondary electrons — now, these secondary electrons come off, and they’re very low energy, so they don’t have that relativistic energy that the beam has, so you have this — if you can imagine this growing cloud of low-energy electrons that are produced at the walls, and under certain conditions, they can spread into the vacuum chamber, and now the primary beam has to now pass through this background of low-energy electrons. And then they can affect each other. So, that cloud of electrons, we call that the electron cloud. It’s this background of low-energy electrons in the vacuum system. And it has an electric field. Right? So, it can affect the primary beam through the electric field, and it can end up shaking the electron beam. It can end up defocusing the electron beam. So, the electron beam is no longer tightly focused. It blows up. And so, this typically goes against what the machine — what the electron beam needs to — you want the tightly focused beam for the performance. So, it can also happen in the proton machines, because the proton hitting the wall can also produce electrons — you know, secondary electrons. So, this was a very big concern at CERN, for blowing up the emittance, blowing up the phase space of the proton beam. But then you don’t have the luminosity. [laugh] So, I’m using these terms — you know, for the colliding, for colliders, you want tightly focused beams. Right? So, any phenomena that — we call it blowing up. Blowing up is not used in the same terms as colloquially, you blow up something. It’s not that — it’s defocusing, spreading out. This effect is defocusing the beam so that the beam is no longer tightly focused. It no longer has high density. The B-Factories at SLAC and also at KEK had electron and positron beams, and this electron cloud was having the same effect on them. It was defocusing the beams and preventing reaching the full design performance of the machines — lowering the density of the beams. So, yeah.

Zierler:

How much of a surprise was it that the APS would be so valuable to research users, even beyond physics?

Harkay:

How much of a surprise to me? [laugh] Or a surprise to —

Zierler:

To everybody.

Harkay:

Well, you know, I think there had been an understanding in the accelerator business that all the development was being driven by particle physics accelerators. And to some degree, that’s very true, because particle accelerators for high-energy physics tend to push the envelope. They’re always looking to extend the reach of the accelerators in order for particle discovery. So in many ways, that had been true through the ’90s and — you know, for the ’90s, let’s say. However, I think for precision accelerator physics, the synchrotrons have taken over, I think, in dominance for discovery. So, I think it was not appreciated that the kind of development that would be happening at the electron synchrotrons would ultimately drive new development. I mean, it’s not a surprise to me. I was in that environment, and I saw the talent around me. But I think it took some time for, culturally, to appreciate the type of beam dynamics and accelerator — basic accelerator physics at the synchrotron light sources. Like I say, it was more precision based, not necessarily — yeah, I would say precision research.

Zierler:

What was the chronology on the investigation of high-intensity limits at the APS? When did that get underway, and what were some of the goals in terms of probing those limits of the APS?

Harkay:

The APS was designed for 300 milliamps. That was the design on paper. And the initial operation was 100 milliamps. So, we had a factor of three to push. And this is where we would do — we would have an opportunity once a week or so to do our own experiments on the accelerator, and that’s when we started to explore what happens when you try to increase the current, the beam current, 100 milliamps higher, and that’s where we started to see some of these wake field effects. And then you have to determine: well, what component is causing the wake field? So, you have to design the experiments so you start to discover which components are the ones that are the limit. It turns out that we never operated — even today, we don’t operate higher than 100 milliamps. The X-ray scientists have gotten better about efficiently using the photons that they get. I mean, initially they were probably throwing some of the photons away. [laugh] But they became better at using all the photons that are available, and they never complained that they don’t have enough [laugh] X-rays for today. But the upgrade, we’re going to give them two orders of magnitude more brightness. So, that’s a much bigger leap. Increasing the photons by a factor of 50 percent is just not exciting from a new science point of view. So, there were reasons why we never pushed that.

Zierler:

Now, I’m very well familiar about the lamentations about not being able to operate in higher energies for not seeing supersymmetry, not seeing whatever is beyond the Higgs. In your world, what are the obvious limitations of operating at the energies that you’re able to operate in, and no more?

Harkay:

On the energy side, in the synchrotron business, the higher the beam energy, the higher the power of the synchrotron X-rays. And the X-rays have to be safely guided out of the machine down into the experimental stations. We call them hutches. And on the way, you have mirrors that — there are such things called X-ray mirrors that will deflect glancing angle, deflect the X-rays into the experimental area. So ultimately, the synchrotron power is something that’s hard to handle. I don’t know the number off the top of my head. How many watts per square millimeter? It’s a very large number. I heard the analogy that it’s more power than the watts per millimeter squared on the surface of the Sun. So, you pack a lot of power in those X-ray beams, so the higher the electron beam energy, the higher the power. There’s a power law. It’s not linear with the beam energy. The power of the X-rays is to the square of the beam energy. So handling the synchrotron power becomes the issue. No one is building an 8 GeV synchrotron anymore. All the new generation upgrades are 6 GeV. So, we no longer have to rely on pushing the beam energy higher and higher to get higher power X-rays. We’re smarter. Instead, we pack them at higher density. We’re able to pack the photons at higher density, and that’s how we get the higher brightness. It’s not by just — it’s not brute force anymore.

Zierler:

And this gets me to a question I meant to ask earlier. In light of all that you’re saying, what are some of the safety considerations in conceptualizing this project, and heaven forbid, what would a doomsday failure look like? What kind of breakdown might happen?

Harkay:

[laugh] Yeah, this is right up my alley. You know, when people think of particle accelerators, they think that — oh, radiation. That’s the biggest concern. It turns out that radiation is not — is a big concern, but electrical power is as big of a concern. But I’m not going to talk about the electrical power safety. Let me talk about radiation safety. So, we have to shield the effect of these losses. I’ve mentioned that you always have some electrons that escape from the vacuum system. They hit the wall. They hit something. You don’t stop the electrons. Electrons didn’t have the high energy, and they create what’s called a shower. So, you have a wall; you have a magnet. An electron goes through, it interacts with the molecules in that material. It makes secondary electrons. It creates photons. It creates neutrons, and then these neutrons just — electrons keep going. So, you have to build shields, so you have a concrete wall around the machine. You have lead shielding in certain places. So, we’re evaluating this right now for the upgrade, because we had the design for the initial machine, and you know, constantly measuring with instruments to make sure that the radiation is always below the safety limits, goals. So with this new machine, we’re increasing a lot of this. We’re increasing how many electrons we’re injecting into the main storage ring. So, we have to consider the radiation safety of that scenario. So, what’s the worst case? The worst case is a couple of things. One is, let’s say, we have this new machine. It’s designed — now, for 6 GeV, what happens if you put in more — you know, you put in electrons that have higher energy? Well, if you put in electrons that have higher energy, they’re not going to be guided by the magnetic field. They’re not going to follow the correct path through the synchrotron. They’re not going to be — they’ll deviate. And if they deviate, they could hit your chamber and then possibly make a shower of radiation that goes outside of the shielding. So, that’s one of the things, so we have to make sure that we limit the beam energy. A colleague came up with a concept. How are we going to do that? The other thing is, let’s say in the storage ring, let’s say one of the magnets shorts out. If you have one of the magnets that shorts out, again the electron beam won’t go in the right path. It’ll go in the wrong path. So, we have a radiation physicist that’s been looking at all these — we have two physicists. One is doing particle tracking. Okay, if I have this magnet trips off, that magnet trips off. This one has an error of 30 percent. What kind of magnet errors could you envision that would cause the electron beam to go the wrong way, go outside of the shielding? And then we have a radiation physicist that takes those electrons and calculates the shower, and what kind of radiation will you have? So, we ended up with a process of controlling the beam energy, make sure it doesn’t deviate, and then look at — evaluate how much shielding we have. How much shielding do we need? Where do we have to make sure that we’re detecting radiation so that we know that we keep people safe? That’s what people are concerned about. They’re called fault conditions. You know, some kind of fault condition that could cause the electron beam to deviate from its correct path.

Zierler:

Kathy, maybe it’s a chicken-and-the-egg question, but in light of all of your work on cathode research and development, is the idea that better cathodes lead to more successful outcomes for the APS? Or, by virtue of using cathodes in the APS, you learn more about what cathodes can do?

Harkay:

I would say it’s the former. But the cathode research that I did is primarily going to benefit the free electron lasers out there. So, a free electron laser is using a linear accelerator. In a linear accelerator, the performance of the beam — the density of the beam, the intensity of the beam — is a direct product of how they’re born at the photo cathode. We make the electrons by taking some kind of cathode, shine a laser on there, and you get the electrons out. In a machine like the advanced photon — the synchrotron, all of the — anything that happens at the electron gun gets washed out in the rings, [laugh] so that there’s different dynamics in the synchrotron, in the storage rings, that is independent of — well, a better photocathode is not going to help. It’s not going to improve the performance of a synchrotron, but it’s directly related to the performance of any kind of linear accelerator like a free electron laser.

Zierler:

Obviously, cathode R&D is a major field. Who have been your major collaborators, both institutionally and individual people?

Harkay:

What’s interesting about photocathode research is that there was a lot of research going on decades ago, like the ’70s, for cathode ray tubes, they’re called. In the accelerator business, when we were interested in designing better photocathodes, we could not get any interest in the experts in solid-state physics, for example, because they said, “Oh, everything’s been done.” You know? They basically came back and said, “Everything’s understood. It’s all been done in the ’70s.” Well, that didn’t help us, because we needed photocathodes and electron sources that didn’t exist. So, what I ended up doing is, I started collaborating, again with a chemist. His name is Karoly Németh. He’s Hungarian, it turns out. [laugh] And he’s a computational chemist. He knows quantum mechanical computational physics for molecules. And so, I had an idea that, well, maybe you could design a material — from first principles. I know what property I want. I want a high-density, low-energy spread, electron source. Maybe you could design a molecular structure that would have that property on photo emission, basically. So, he combined his knowledge of chemical systems that he knew of from his experience in other areas, and then working together, we developed a number of ideas for potential new photocathodes. And so, we published a number of papers, and then I started working with a former Fermilab graduate student friend of mine. She was now a professor at IIT, Illinois Institute of Technology. Her name is Linda Spentzouris. She had a number of students, and another professor, Jeff Terry, who took one of the ideas, and they fabricated the material and started measuring the properties and see if the properties agreed with the theory. So, it led to — at that point, I got pulled off in other directions, but it led to a rich area of research, both with the collaborators at Illinois Institute of Technology, but basically, I believe that it opened the door in the field of other researches at Cornell and SLAC who were doing some photocathode development. They were looking more at making the cathodes that existed better. You know, making cathodes that had already been discovered, make them work better, understand how to fabricate them and make them work better. But my research with Karoly opened the door to design. You know, I called it “photocathodes by design,” designing them from first principles. It’s not something that you would have, like a solution a year from now. It’s a longer development, because you’re sort of starting from scratch. So, there is this sort of — in development, they have this — you know, you have an idea, develop it, and then you have to try to get a product at the end. You can have this valley of death. I don’t know if you’ve heard about that. [laugh]

Zierler:

Yes. Of course, yes.

Harkay:

So, that valley of death is a real big problem in our field, because I would say accelerator development in the future, a lot of it has to do with materials. You know, improved materials, improved superconducting materials, improved photocathode materials. And you always end up with this support for basic fundamental research, but then how do you get that into a final product? You have to show that it works. You have to go through prototypes. You have to show that it can be a production quality. Right? Because the Department of Energy is going to say: “Yes, build this machine for me, and base it on this technology.” They’re going to want it based on known technology. They’re not going to say: “Oh, take 10 years, and tell me if this is going to work.” So, that’s tricky. That’s tricky to get the support for that kind of work in the lab system, I’d say. And if we could improve that process, I think it would — and many people are working on that, and NSF and DOE have built these centers for photocathode research, and they are supporting that effort. So, I believe that I played a role in that, and it makes me very happy that a lot of people that picked up on a more sophisticated look at using fundamental principles of photoemission, you know, understanding photoemission and designing materials to have certain properties. I look back at that, and it makes me very happy that I contributed to that.

Zierler:

To go back to this theme of basic versus applied research, I know it’s beyond your purview, but in what ways have advances in cathode R&D led to advances in the industrial or commercial applications of cathodes?

Harkay:

My collaborator, Karoly, went off — built his own company, [laugh] and he got interested in battery research. So, the idea of going beyond lithium — you know, batteries, building your rechargeable batteries and long-lasting batteries, higher energy density batteries, is a big deal. Right? And a lot of the batteries in your laptop and cell phone are based on lithium. So, going beyond lithium is probably going to be a big deal. A lot of people are working on batteries and cathode development in batteries. A cathode is a cathode. You can use electric fields. You can use chemistry. You can use photoemission — different ways to pull the electrons out, but ultimately, the material properties of the cathode is going to determine the performance of that cathode. So, I don’t know [laugh] if any other researchers at these other laboratories that I mentioned are applying their cathode research to industry. I’m not sure, but this is one example that I can think of, where the expertise developed within the photocathodes is now being ported to battery cathode research.

Zierler:

On the administrative side of things, how much did your day-to-day change when you were named accelerator physics group leader in 2003?

Harkay:

Being a group leader meant that I had less time for my own research, so definitely it transitioned more to providing ideas for my colleagues to carry out. So I would say that I had a bigger picture of what we would need — you know, priorities of what, as a group, we should be working on. And then encouraging — finding the right colleagues in my group and outside of my group to work on certain projects and then supporting them in that role. So that changed. I also had an opportunity to mentor postdocs during that period, which I had played a role in hiring, and then mentoring them, so that was a very satisfying experience as well. One of them, Yine Sun, was a postdoc during that period, and then she went off to Fermilab, and then she came back, and now she’s a very successful scientist at APS. So, it’s great to see how her career started at APS, and then she became successful. And also, I think — and I know this — that APS has a very good reputation in our field. So, when I had a postdoc, and they were ready to look for a regular job, they were sort of grabbed by other laboratories, because they knew that the work that they did at APS was high-quality, significant, and all that. And so, they became very marketable when it was time for them to look for another job.

Zierler:

Now, as group leader, would you have direct contact at the DOE, or that’s still above your level?

Harkay:

That would have been above my level. Yeah.

Zierler:

So who — just to give a sense of the org chart, who do you report to as group leader?

Harkay:

I was within the accelerator systems division, and I’m still in the accelerator systems division. And the Advanced Photon Source as a whole has three different divisions. So, accelerator systems, APS engineering support, and X-ray science. So, this is — a division director above me, and then there would be the overall head of the APS above that, and then the lab director.

Zierler:

Right. Of course. Back to the science, Kathy. What is a superconducting undulator, and how does it relate to the overall mission of the APS?

Harkay:

I was talking before about synchrotron radiation. I think I called it synchrotron radiation — this property of accelerated electrons producing — you know, converting their energy to radiation. We call that synchrotron radiation. Now, you can do this with a simple dipole bending magnet. It just makes one arc. Right? And then, you have X-rays coming off at a tangent along that track. An undulator — I don’t know where this term comes from, but an undulator is an array of short-period magnets, dipoles. You know, it’s an array of dipoles, with alternating field. And so now, when the electrons go through, they execute sort of a wiggle. That’s why they call it an undulator. So, it executes small bends throughout the entire length, and that ends up producing synchrotron radiation that’s directed in a straight line. Forward directed is more intense. Now, a superconducted undulator is able to create a higher magnetic field in those short periods. The traditional, conventional undulators are made from permanent magnets. The superconducted undulator can produce higher magnetic field with that same period, so you end up with the possibility of much higher brightness photons, higher brightness synchrotron radiation produced in a superconducting undulator. It was Bob Kustom, one of my biggest mentors at APS, who got me involved in this project at APS. I was responsible for calculating the heat loads on the SCU by the beam. This lead to a PhD thesis by my student Laura Boon, from Purdue.

Zierler:

What are some of the intellectual and academic considerations when you have an idea that might be worth a patent? What goes through your mind? What are your motivations? What are you seeking to protect in going through that process?

Harkay:

In my case, the patents have been in photocathode technology, photocathode concepts. This particular development happened under support — a lot of work was supported by Argonne. So, Argonne — let’s say you have this idea, and you want to — you think it’s a good idea for a product, you know, that goes beyond the accelerator field. So, I mentioned, for example, battery research. That would be a case where you went to Argonne and said, “Argonne, would you be interested in sponsoring this patent?” Argonne’s interest would be — well, if the idea is marketable to industry, then Argonne could get royalties for that. Right? So, the idea is, this is a concept and idea that has applications. We’re not going to be the ones necessarily that develop those applications, because those applications go beyond our mission, but there could be people out there, companies, other entities, that could benefit from that technology, and they might be interested in picking that up and developing it further. Then Argonne could get benefit through royalties.

Zierler:

Kathy, on the service side of things, I’m curious about your work on committees that focus on women in science. What have you learned from the vantage point of the committee world that has that sort of bird’s eye view of the field? What have you learned? In what ways has the field changed for the better, and in what ways is there not nearly as much progress as there should be?

Harkay:

That’s a big question, like a huge question. [laugh] Let me start by talking about WIST, Women In Science and Technology, at Argonne. WIST has visibility at the lab director level. It’s probably been 20 years now that it was first started at Argonne. So, WIST has a specific managerial structure, but it also has sort of an informal structure as a collection of all the women in science and engineering at the laboratory. So, I never had a role at the lab director WIST steering committee level, but it was WIST that let me meet and become friends with other women scientists at the lab. There aren’t many women scientists and engineers at Argonne and most of the DOE laboratories. I think it’s about — maybe it’s better now. Maybe it’s 15 percent now of the scientific staff, engineering staff, are women. Back then, it was 10 percent, few and far between. We’re kind of scattered across the lab — don't work with each other on a regular basis, but it was through the various activities sponsored by WIST that I got to meet these other women at my level. And that was huge, because we would then share information about what’s going on in different parts of the lab, in a way that — I was not getting that information. All the anecdote information about how things are done, how decisions are being made, what’s happening at this level and that level, and this department and that level of the laboratory. Those conversations happened with me and my other women science colleagues in a way that — I didn’t get that information flowing to me, you know, through my other channels, through my male [laugh] hierarchy.

Zierler:

Kathy, specifically what — I’m sorry to interject — but what kind of information are you referring to?

Harkay:

Well, like — you can become isolated and pigeonholed working on your research. You know, you work on your research, you do this, but you may not know that there are things happening on a bigger scale that affect your career. You may not find out about these things, and then you can’t make decisions based on that other information. It’s hard. I’m not sure that I can give a specific example. Just like, knowledge is power, just knowing that decisions are being made. I mean, I don’t know that I have a specific example.

Zierler:

I guess an example where it’s specifically relevant and useful that women at the laboratory are sharing information. Like, what specifically about it is that that makes this useful and important?

Harkay:

I’m trying to think of an example. Oh, you know, David, this is hard to define, like specific examples. I mean, just —

Zierler:

Is it always scientific and substantive, or is there sort of a — like a support network in some ways?

Harkay:

Not — no, no. It’s not — it’s more than support. It’s not scientific information, but it’s decisions that are being made at the laboratory level. Like, let’s say the laboratory is creating a leadership institution, and the leadership institute is starting a leadership training program. Well, unless my division director comes to me and says, “Kathy, are you interested in a program under leadership training at the laboratory?” he may or may not tell me, but then, my women colleagues said: “Oh, here’s this opportunity. Go talk to your division director about this opportunity”. And then it happens. You know? This is maybe an example. Anyway, so it’s understanding and learning how we, as women, can take part in opportunities that the lab is offering that we’re not getting the information about otherwise. Those opportunities are going to other people and not — and we don’t even know about them. [laugh] Now, this might be just one example of, you know, a leadership institute with — a leadership opportunity that you may not have heard about otherwise. Things are getting better. I mean, those communication networks are getting better now that the laboratory is much more attuned to diversity, equity, and inclusion, and so there are committees at all the different divisions at the laboratory. And we meet, and they talk to each other, and we communicate with the employees. It’s a lot better now than it was in the early stages of my career. So, I think it’s all about communication, telling your employees about things that they might be interested in. I got the impression that sometimes management would hold that information, just hold the information, and not disseminate information. So, it’s just — you know, from a professional point of view, if you don’t know that an upgrade is being discussed, then you don’t know that you can let them know that you’re interested in getting involved. Your management may not know, or they may not think of you, when they parceled out the important jobs. You know, if you don’t have the visibility for whatever reason, then this can affect you from your career point of view. If you don’t have the visibility because, let’s say, your management is not aware or considering the women, which happens sometimes, they might give the jobs to a network that doesn’t include the women. And that can be detrimental to the women’s careers. Right? It’s either the unconscious — you know, all these things that we’ve learned about in the last five, eight years about unconscious bias. It happens in search committees. Right? It happens in hiring decisions. It happens in getting employees visibility. In each one of those areas, there’s a bias toward white males, then you multiply all those factors, and you end up with the women and unrepresented minorities not having the opportunities. Right? So, things are getting better. Things are definitely getting better, but those networks, search committees — there’s much more awareness of how to be aware of unconscious bias, which is very difficult. [laugh] Very difficult to do. But also increasing equity, basically.

Zierler:

Kathy, to what extent is this at least resolved, in large part, by having more women in leadership positions? And alternatively, even if that were the case, how might these challenges be more structurally embedded in the system, where even that might not be a balm to solve all these things?

Harkay:

I agree 100 percent with what you said about having women in leadership positions. I would say that solves a lot of problems. I can remember where I was asked to be on a search committee for a division director at the APS. I was the only woman in the search committee. And we had an in-person meeting where we were talking about possible candidates, and all the candidates that were discussed [laugh] till that point were men, and then I remember one person looked at me, and all of a sudden, he said, “We have to think of some women.” That’s all it took. So, the fact that I was there just opens the horizons of the other members. And I wasn’t even really [laugh] a senior scientist at that point. So, it can be something as simple as that. It’s also true that I have a network of colleagues in my field, around the world, and I probably have a stronger network of women scientists and engineers. So, I can then identify possible candidates for particular positions that the search committee may not know. They may not know these people. And I think — I’ve come to understand that there’s a sociology behind hiring decisions that we think that scientists — or scientists, I think, would like to think of themselves as being objective. All our decisions are based on data. We’re objective in every way. But it’s not true. [laugh]

Zierler:

Not even a little.

Harkay:

[laugh]

Zierler:

I’m very well positioned to appreciate that. I talk to scientists every day.

Harkay:

Yeah. Yeah. So, this is definitely a sociology behind hiring decisions. And you were asking earlier about structural difficulties. If there’s a system where hiring that manager — you get a position — here, hire someone, and hire someone quickly, because otherwise, I’m not going to have the position anymore. Well, that formula is detrimental to equity and inclusion, because it would rely on…

Zierler:

A network.

Harkay:

…the network in your head, and it’s not the network — it’s not a broad network. So, anything where you have a pressure of “hire, and hire fast,” you have to have a person come in and, off the bat, off and away they go. A person would want to hire someone they know: someone they know, someone who knows someone who knows. I remember being in a hiring situation, and I mentioned some people — the question I got: well, who do they work for? Do I know someone that knows them? And they didn’t, and so they felt uncomfortable. They didn’t want — they were uncomfortable with that candidate, because they didn’t know the person. They didn’t know anyone the person worked for. They didn’t know the institution. They didn’t have women in that network. So, the more structurally — if you structure it so that you give hiring managers support and resources, so that they have the support — you know, recruiters that do have those networks to find the best person. Because ultimately, you always want to find the best person for the candidate — the best candidate for the role. Right? And it could very easily be outside your own private networks.

Zierler:

To what extent do you see last year — and hopefully, it’s an ongoing conversation — where STEM focused so much on a racial reckoning? To what extent do you see that in parallel with the issues of inclusivity of women in general?

Harkay:

That is such a deep, deep question. I’m not an expert in these things. I think we’re all trying to understand what’s happening and how to make it better. The fact that women — I mean, people of color have these barriers to overcome, from the get-go, it goes so far beyond my experience as a woman. I think I have some understanding about it because of being a woman scientist, because I’m underrepresented in a male-dominated field. So, I feel that I have some understanding of what unconscious bias means and how it manifests itself, as I follow my career trajectory. But for people of color, it’s an order of magnitude harder. And so, I would like to believe that I could be an advocate, but understanding exactly what someone would need is — none of us can do that alone. It really has to come from discussions and conversations. And if you think of the talent pool among our Black and brown brothers and sisters, it’s enormous. Enormous talent pool out there. I was just thinking about athletes. I was browsing through, looking at athletes. Like, in track and field — now, in gymnastics, the top gymnast woman in the world is Simone Biles, who is Black. It’s just an enormous talent pool out there, and even in the last year, there’s just so much more — you know, I’m hearing so many more interviews and reading books from Black and brown people, and it’s tremendous. I mean, there’s so much talent out there. So, if you think of talent in science and engineering, it’s out there. What have you lost by not including this talent? For years and years, we’ve been trying to increase the participation of women in science and go back and forth between reaching out at the high school level. [laugh] You know, K through 12. When do you do that, and then how do you measure how well you’ve done? It’s very difficult. So, I’m just not sure how — I certainly don’t have the answers. [laugh] Personally, what I’ve tried to do is be a mentor and role model to women a little bit more downstage. I think it’s because I can see a direct connection between — it’s easier for me to see a direct connection between — I can watch that person grow in their knowledge and expertise and give them the guidance they need to succeed in a career in physics, for example. You don’t have that direct feedback if you go to a high school and give a talk, although surprisingly, you could find out years later that that student will come to you and say, you know, “I heard your presentation, and that’s what inspired me to go into physics.” That’s really important to do. That’s really critical to do. You as an individual don’t get feedback in that case, so you don’t know how effective that is in attracting and keeping the women in science, and ultimately, we want to do the same for underrepresented minorities. This is a big goal, but it goes through all of society, not just STEM.

Zierler:

No, but the point is, is that STEM is not aloof from the rest of society — that what happens in society is happening in STEM, and vice versa.

Harkay:

Right. Right. And we need help in STEM, because in STEM, you’re not trained [laugh] in sociology. You’re not trained in unconscious bias — the training you get in STEM does not lend itself to overcoming societal issues. How should I say — you know, scientists solve societal problems, yes, but they’re — I don’t know how to — that’s a good thing to think about. I think scientists and engineers, in physics at least, are not — they’re not experts [laugh] in human behavior. I think a lot of these big societal questions come down to education and the ability — the open-mindedness, and scientists certainly have that. You know, the scientist has to be open-minded to discover, for discovery. You have all the skills. You have the open-mindedness, you have the education, your curiosity.

Zierler:

There’s also — I mean, just to state the obvious — the scientific value of different perspectives…

Harkay:

Right. Right.

Zierler:

…that have a national, gender, sexual, religious, cultural orientation.

Harkay:

Right. Right.

Zierler:

That different ways of seeing the world actually leads to better scientific outcomes, because different perspectives are needed. That’s not a controversial statement, I don’t think.

Harkay:

It’s not controversial to me. But I know that that was not accepted. That was not a foregone conclusion early in my career, for sure.

Zierler:

Of course.

Harkay:

Yeah.

Zierler:

That’s why the question I asked was big, that got to the larger idea about — over the course of your career, what’s changed and what has not?

Harkay:

Yeah. Yeah. You know, I knew all of that going in. I knew that perception, that women just weren’t as capable. I knew that perception. I didn’t get that perception directly from people that supported me, as I mentioned earlier. But my view of success was always not to try to — was to, through my direct interaction with a given person, to show them what I was about, what I could do, that I had it, to convince people [laugh] one by one. One by one. I couldn’t tackle the whole world. There’s no way I could have tackled the whole world. I think ultimately, that’s what it is: individual relationships. If you know the person, and you’ve talked to them, and you know what they know, and you share, you work together, and you share the love of science, and you bring skills to the table, and they complement the skills of the other person, that’s what ultimately — that will convince anybody that, hey, this is a good thing. You know? I benefited from this relationship. So, it’s been a push. I feel I have succeeded, after these years, that I have a different skillset than some of my male colleagues. There’s no question that I have a different skillset. It’s recognized now. It’s been recognized now that the skillset that I have is benefiting the lab as a whole. I always knew that, but it was not always [laugh] a foregone conclusion. And so, did some of my energy have to go into convincing people? Yes. Could that energy have gone into doing science instead? Yes. Wouldn’t that have been better? Yes. That would have been better for everybody. But I’m very stubborn, and I wouldn’t let anyone derail me. So, I just kept at it. But anyway, how many people have you lost, that — where the barriers were too high?

Zierler:

People that were on great trajectories, but they just couldn’t stay in the field.

Harkay:

Right. Right. Right, because of some egregious behavior that I didn’t experience, but that I know people have experienced. Yeah.

Zierler:

Kathy, back to the science, how about?

Harkay:

Yeah.

Zierler:

I’m curious about the upgrade. I have in mind the planned shutdown schedule of the LHC, where it’s baked into the overall enterprise. Right? They know when it’s going to be on. They know when it’s going to be shut down. To what extent was the upgrade, the decision for an APS upgrade, a foregone conclusion early on? And to what extent was it about real-time assertations of what the APS was and was not able to do over the course of its time in being?

Harkay:

Precisely the definition of what the upgrade was going to be went through a couple of iterations. One of the early iterations was just an evolutionary upgrade that did not involve a major shutdown. The concern was that our particular users, the X-ray scientists, would not accept the shutdown. You would lose them. If you shut down, they would migrate to other synchrotrons, and they would never come back. So, this was an idea that the X-ray users would not find any kind of shutdown acceptable. What that means is that the only kind of upgrade you could envision was what I’m going to call evolutionary. It’s just incrementally better than what you have now, you know, 50 percent kind of stuff. And is that really worth it? [laugh] No. In the end, that was not worth it. So basically, [laugh] the door was opened to, well, what could you do if the shutdown was not a concern? Then, it opened the door to this fourth-generation synchrotron that we’re building, and it’s ultimately the right thing to do. It’s orders of magnitude better. That makes it completely worthwhile from a user facility point of view. And it took socializing on the users’ side to demonstrate what this source can do for you, what science it will enable, and then it got the X-ray scientists excited. So, they are on board. That was a harder sell, because it’s not a mode the X-ray users are used to. That’s very different from a high-energy physics facility. So, that’s what I would say, that the different synchrotrons are synchronizing their downtime. This is a trend now. The major synchrotrons are upgrading to these fourth-generation synchrotrons with the extended downtime, but now we’re coordinating our downtime so that the users from one synchrotron can go to — you know, have a place to go while they’re waiting for their machine to get upgraded. And so, this is working well. There’s been enough time for our users to come up with how they’ll make use of that downtime: analyzing data, upgrading their beam lines, upgrading their data handling capabilities, that sort of thing, or migrate their experiments to another facility temporarily.

Zierler:

To what extent were diminishing returns in the data a part of these considerations, that the APS, at a certain point, was doing all that it could do in its current formulation?

Harkay:

Are you asking whether APS has sort of hit a limit?

Zierler:

Or a wall, I mean, in terms of its value, absent an upgrade. Is there still all of the optimism for what it could do, that was there even from 1995? Or, my question is: were those returns diminishing at some point?

Harkay:

Well, we are definitely upgrading before we hit that diminishing return wall.

Zierler:

Okay. Good. So, there is a sense that that would be coming, absent a proactive upgrade?

Harkay:

Yes.

Zierler:

Got it. Got it. So what might be some examples? What justifies this massive project? What could be done, best case, as a result of the upgrade being implemented?

Harkay:

It’s always about the science. It’s always about the science, and I’m not an expert in the science. [laugh] So, I leave that expertise to the experts. It goes back to what I was saying about — you know, understanding the properties of materials, biological systems, chemical processes, under real conditions. “Real conditions” means that the extreme environments, higher pressure, low density with the nanoparticles — and in order to probe those systems, you need a higher brightness probe, which is — the synchrotron X-rays that we’ll produce with the upgrade. You’re opening a world that we don’t even know. I mean, we have inklings of this world. [laugh] You know, inklings of what’s possible. I’ve seen images of a system, and it’s like this hazy, low-resolution system, and then someone will have done a simulation that — if that system had this property, I modeled it. This is what I could see if I had an X-ray upgrade. So then the question is: well, now we build the upgrade, and we see if that’s true. [laugh] You see if that theory really fits, or if you discover something brand new. We’re really going into a new world with this. You’re opening up a whole new world with this APS upgrade.

Zierler:

“Upgrade” suggests singular, but obviously there’s many parts of the upgrade. I wonder if you can address that both on the hardware side and the software side.

Harkay:

Well, one of the things on the software side that is definitely going to be needed is more sophisticated data reduction. You know, we’re already generating terabytes of data. Every photon interaction with some sample is generating raw data — all kinds of raw data. You have to analyze and process that data. Right? Otherwise, it’s not useful. What we’d like to do for this machine more, and certainly in the APS upgrade era, is to provide users with easier access in that you bring your sample, you do your experiment, and we give you processed data that you can then draw your conclusions from and apply to your theory, compare to your theory, etcetera. It’s not useful to give them [laugh] terabytes of raw data. So, what will it take to process the data? Handling massive datasets. You need supercomputers. And people are also talking about machine learning and artificial intelligence to process data. Machine learning, artificial intelligence. This is like the buzzword [laugh] of the 21st century. Right? Artificial intelligence has been used very extensively by Google and Facebook to do social engineering of various kinds. In the sciences, it’s much more than just image recognition. It’s much more than just recognizing a bunch of — you know, a cat in an image. It’s going to involve understanding and processing datasets, where it will definitely involve pattern recognition in data. We’re bringing in AI and machine learning experts to come and work at the APS, for example, and it’s happening at other accelerator facilities as well, so that we can apply these techniques in a practical way to make accelerator operation smoother and understand how to apply it in the data reduction that I need. The APS upgrade accelerator is going to be much more difficult to operate than the present one. The present APS is very forgiving. You know, you could be a little bit more sloppy with how you set up the magnets and set up the diagnostics and trajectory. It basically works in a pretty broad range of these parameters. But the new machine will have a much smaller, [laugh] smaller area of smooth and stable operation, so we’ll have to control all the magnets, the diagnostics, the trajectory control, the energy control. All of these things will have to be controlled to a much higher level. And so, we’re all thinking that machine learning in particular will play a much bigger role in controlling this machine. A machine like this, in the future to make bright and stable beams and analyzing these massive data sets.

Zierler:

Kathy, I know it’s a bit far afield, but operating in a national laboratory environment, I’m curious if anybody is starting to talk about the potential value of quantum computing in all of this data analysis.

Harkay:

So, I’m not an expert. We have an advanced computing center at Argonne, and we have workshops on quantum computing. I just haven’t had the bandwidth to get connected into that field. I’m just not going to be able to say anything [laugh] intelligent about it. Sorry.

Zierler:

What about trends in terms of who’s coming up in this field? Because when you’re talking about as much data as you have to deal with, computational power only gets you so far. You still need brains to understand what the data says.

Harkay:

Exactly. Yes. I just don’t know what those brain — yeah. The machine learning part is sort of the pattern recognition part, pulling signals out of noise. Right? I just don’t know enough personally about quantum computing that I could tell you that this is what’s going to be great about quantum computing in this application. I think quantum computing speeds things up. Yeah. I’m sorry. [laugh] I just really don’t know. We’ll have to be smarter. Definitely smarter computing, not just — it’s not the brute force. Right?

Zierler:

Yes.

Harkay:

It’s not just cranking, cranking, cranking. It’s being smarter about how you compute. In the parallel —

Zierler:

Well, of course Kathy, you’re in good company, because even people who do nothing but think about quantum computers, they don’t even agree on what quantum computers will be good for.

Harkay:

Oh, right. [laugh]

Zierler:

So, it’s very much an open question. [laugh]

Harkay:

Yeah. We have several physicists that I work with that lean towards computing, so they understand how to make better use of the computing resources that we have by, for example — how do you parallelize the problem that you’re working on? You need an understanding of physics to do that. Instead of just serial calculations, just from start — this is where you start, this is where you end — but then you could think of speeding it up by doing several things in parallel, where you know in physics that those don’t — this one doesn’t depend on that one. They’re independent, so you can run them in parallel until you get to the end. But you have to have an understanding of physics to know how to do that. So, even with the computing, you need the two sides working together. Right? You need the big minds working on what a quantum computer can do, and you need the people that have — you know, what’s my computer limitation now, and how do I make use of that? So, there has to be big learning on both sides. I think in accelerator physics, the accelerator science side, we’re picking up and trying to learn the machine learning part, so that we can then apply it. But you have to understand it first in order to apply it. So, I really truly think — you know, my overall philosophy has always been that we make progress when you bring two disciplines or many disciplines together, and then you make something new. You know, I’ve seen this in my own career, and it really opens the horizon. I think it’s great. [laugh]

Zierler:

Just to bring the conversation right up to the present: what are some of your responsibilities as machine manager of the particle accumulator ring?

Harkay:

John Galayda, who we spoke of earlier, set up this construct where he had a physicist act as machine manager, but of different parts of APS. So, we have a linear accelerator, a particle accumulator ring, a booster, and a storage ring. So, we have a physicist who is the machine manager, and then we have a deputy. So, my job is PAR machine manager. The machine manager is just a role. I don’t have a group behind me. I’m watching and looking at the physics of the particle accelerator, the PAR, and also the operations of the PAR. And now, since we’re doing an upgrade, I’m also looking at the upgrade of the PAR. So what does this mean? It means that if someone wants to — if I decide that we need to improve the function of a diagnostic in the PAR, for example, then I find other physicists, I find other engineers, that will look at this and tell me how — I will define how it needs to function, and then they will work on: how do we make this happen? Right? So, the machine manager’s role is to identify what improvements need to happen in the machine, and then you work with other people to get that done. So, if in the operation of the machine — let’s say we’re running the APS, X-rays, and something happens in the PAR. Something breaks. We have the operators, and we have the operations specialist, that can solve a lot of those problems. If it happens to be equipment that fails, you know, they’ll know how to get the person to fix it. But it might be an unstable beam. It might be a beam dynamics question. Then I get a call: “Hey, the beam is oscillating. It’s not making it through the PAR.” [laugh] “It’s getting lost before it makes it to the end of the cycle — what’s wrong?” And so that would be a physics question that I would address. Given that this PAR has been working very well for 25 years, there’s very few [laugh] physics problems left. So, what we’re focusing on is: we’re pushing it so that it performs five times more charge than what it’s doing now. So, that’s where the physics question comes in, and so now I look at the physics limitations, you know, going back to my true love, [laugh] my first love intensity limits and then how do we overcome them and build a project — build a program from there. It works very well because you have a physicist who has a corporate memory, you could call it. If I don’t know something, I’ll ask the previous machine manager. That person is retired, [laugh] but he’s still around. And so, we understand these machines very well, so we remember: “Oh, that happened eight years ago.” [laugh] “This is how I solved it.” So, it’s a bit of a way for — to have expert eyes on the different machines, someone that knows the machine very well and can resolve issues and make sure that the performance is up to snuff.

Zierler:

Kathy, for the last part of our talk, I’ll ask a broadly retrospective question about your career, and then we’ll end looking to the future.

Harkay:

Okay.

Zierler:

So, I asked you at the beginning really big, broad questions about the APS, and I did so because your tenure with the APS is so unique, I knew that your answers would have an institutional imprimatur about them, even though, of course, you’re only speaking from your own perspective. But for you personally, what has been most satisfying in all of your work on the APS, either in terms of a collaboration that was really special to you? A particular person that was so important for you to work with, an engineering hurdle that you overcame, or just something in basic discovery that was really cool to be a part of? What really sticks out in your mind as things that have been most fulfilling to you as a scientist?

Harkay:

Well, many of them are what we already talked about. So, Richard Rosenberg just retired, and we were sharing some memories together, and both of us feel that the work we did on electron cloud was one of the highlights of our careers. The detector that he designed, you know, we installed it, we did experiments together, and then I was the one giving talks at [laugh] all the workshops, at all the conferences, on our work in the accelerator field. That detector has been picked up and used and developed further, and I don’t even know that everyone even remembers where it came from. But it’s so satisfying to see that this is now the standard diagnostic. You know, it was never designed for this purpose before, and it came from someone with a surface science background. So, it really enhanced our understanding of how to even measure these things. So, this gives me tremendous pleasure — you know, it’s led to student work, thesis work. I have a colleague who did his thesis work on electron clouds at Cornell, and now he’s at APS. He’s the booster manager now, and he’s doing great stuff. That just makes me feel very, very happy and proud. The photo cathode work is also something I’m very proud of, because it’s not traditional accelerator physics. You know? I took — solving a problem, and it wasn’t even for us. It was for someone building a free electron laser. But I was interested in the ideas of it. I’m interested in the physics of it. So, bringing together a team, it was an LDRD project: a lab directed research and development project that I was able to do this. And now, the idea of designing materials from first principle is to get a photoemission property. This is now an accepted technique in the research field, and that is basically — you know, I was very proud and very happy it’s led to, again, student’s papers — you know, a number of papers with students, led to launching their careers. It’s very, very satisfying, and ultimately what I can’t wait for is for the APS upgrade to be built, because I think there, I will see the ideas that I had, the ideas in collaboration with my colleagues to accomplish this upgrade and see it happen and see if — I’m sure it will be successful. That will be the ultimate satisfaction. [laugh] So, I’m really looking forward to that.

Zierler:

Kathy, that’s a great segue to my last question. Based on that optimism, based on what the APS could do in the future, of course with every major scientific project, there are binary choices. There are mutually exclusive choices about what projects to fund and what not to fund. To the extent that all of these projects rely on tax dollars, what are some of the most efficacious ideas to convey to the broader scientific community, to the federal policy scientific community, that really underscore why this upgrade and why the future of APS is so important?

Harkay:

Yeah. You know, communicating science to the general public is extremely, extremely important, and it’s something that I think we have to do better. Specifically, in APS’s case — so, with SARS-CoV-2, APS played a huge role in the past year in X-ray sciences imaging the protein related to the virus, the spike protein. The development of the vaccine was dependent on knowing how this protein looks. But it’s not just how it looks. It turns out that this research started back in 2013. That was not at the synchrotron, I don’t think, but research into understanding how respiratory viruses infect human cells started with a respiratory virus — I don’t remember what it’s called — back in 2013, where they did develop — they imaged the structure of the protein, similar — it’s corollary to the spike protein — and they developed a vaccine. It didn’t work. What they discovered was, it was because that protein had two forms: one form was the way it looked on the virus. The other form was how it changed when it infected the cell. So, you had to develop a vaccine by freezing the protein or stabilizing the protein in the right form. That was what you had to do. And when they understood that, they — and MERS came along. MERS is also a coronavirus — 2015 and 2017. They took this understanding. They imaged the protein. They calculated the two forms, and then they produced a vaccine against the correct form of the protein, and they developed a vaccine that worked. That one works. It didn’t gain much traction, because MERS didn’t become a pandemic. It didn’t affect everybody. However — okay, now CoV-2 comes along, same thing. It’s a coronavirus. The same thing. You need to do this trick of the protein — freeze the spike protein in the correct form. Then you have the information that can go into the development of that vaccine, and APS played a huge role in developing that database. You know, doing the measurements of the molecular structure of those proteins. So, that basically went into the development of the vaccines, and it looks like from the outside, the vaccine was developed — there wasn’t enough time. [laugh] You know, how do you do that? But there’s this whole history behind it. And you know, we have to do a better job in communicating this to the public, because this is like probably the best example I can — I could think of other examples too, but this is probably the best example.

Zierler:

It’s certainly one that hits home right now.

Harkay:

[laugh] It totally hits home.

Zierler:

Kathy, it’s been so fun and important spending this time with you. I’m so glad we were able to do this. Thank you so much.

Harkay:

Well, thank you for your probing questions. [laugh] And yeah, thank you very much.