Transcript

Working with the Synchrotron

Peter Kappen
Email: p.kappen@latrobe.edu.au

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Matt de Neef:

Hello and welcome to another La Trobe University podcast. My name is Matt de Neef and today I'm speaking with Dr. Peter Kappen. He is a Synchrotron Science research fellow in the Department of Physics here at La Trobe University. Thanks for your time Peter.

Peter Kappen:

Great to be here, thank you.

Matt de Neef:

I wonder if we could start today with a bit of a look at the Synchrotron itself and the basic question and I'm sure we are going to ask plenty of times, and that is what is a Synchrotron for listeners that might not be aware of what Synchrotrons are.

Peter Kappen:

In a nutshell, a Synchrotron is a great big machine that produces very intense beams of light. That is why we call it Synchrotron and sometimes I would say Synchrotron light sources. And this Synchrotron light has some special properties really, and one of the most striking properties and most special property is about Synchrotron light is that it comprises all sorts of colours or wavelengths ranging from infrared, which is heat radiation or heat rays through visible light, through ultraviolet light all the way into the x-ray region.

And x-rays are cool because with x-rays you can shine through materials and matter. Imagine, for example, if you have got a broken bone or broken wrist, you go to the doctors and get an x-ray taken. You can do similar things at a Synchrotron for medical purposes but also for all sorts of other purposes such as studying chemistry or the structure or the make up of materials in very fine detail. You can look at environmental problems, you can look at protein crystals and develop new pharmaceuticals and drugs, you can look at archaeological problems and materials to look at how things were made a few thousand years ago, and these sorts of things. So there is a whole raft of opportunities to use Synchrotrons as research tools.

Matt de Neef:

Of course, the Australian Synchrotron was built a few years ago down the Monash University in Clayton. What is La Trobe's relationship with the Synchrotron and how does your role fit into that?

Peter Kappen:

La Trobe University is part of the South Australia-La Trobe University Foundation Investor Consortium of the Australian Synchrotron. That makes La Trobe University the third largest university investor into the Australian Synchrotron. What that means is we get, apart from access that we can apply for through merits regimes, we also get preferred access or we call that often foundation investor access where we have certain amounts of time guaranteed per year that we can spend at the Synchrotron.

We share this time with South Australia on a 50-50 basis. We have got a very amicable relationship there with the South Australian group. Overall, it means that we get, on top of whatever we do, we get some preferred guaranteed access. In this sense, La Trobe fosters a very strong relationship with the Australian Synchrotron. So we are running the La Trobe University Synchrotron program and my role here as a Synchrotron community liaison is to develop our user community, to foster our user community, to talk to people about how Synchrotrons can benefit their research, boost their research, what they can do in various fields.

So this program is university wide, it is primarily based in the Science Faculty at the moment but it also reaches out in the Humanities Faculty. It is primarily based at the moment in the Bundoora, Melbourne Campus but it also reaches out to the other campuses in Wodonga and Bendigo. So from that point of view, we are a university wide activity -- university wide program. And my role within this program is as I said, to foster the community, to develop the community, to make sure that we are always using not only our Foundation Investor Access time properly and fully but we are also using merit-based time at the Synchrotron.

And we use the time for all sorts of purposes; primarily for research or feasibility studies, to enable research, but also for teaching and outreach projects.

Matt de Neef:

Now, I believe you completed your PhD in Hamburg where there is a similar Synchrotron facility. How similar is the facility there to what we have got here in Australia or is it a case of all Synchrotrons are relatively the same or are there massive differences between them?

Peter Kappen:

We have got about 40 to 50 Synchrotrons around the globe and they come pretty much in three sizes or three categories. We have got whopping big great machines. There are only four Synchrotrons around the world. One in Chicago, that is the Advanced Photon Source, one is called SPring-8 is in Japan, and two in Europe; one in Grenoble, European Synchrotron Radiation Facility and just very recently opened, one in Hamburg. So these are the four very large machines. And then the majority of Synchrotrons are sizeable fairly large machines and the Australian Synchrotron is pretty much at the top-end of that range.

Then you have got a number of smaller Synchrotrons around the place. For example in Singapore, you would find a small Synchrotron, one in Sweden, one in Thailand and so forth. Overall, the Australian Synchrotron compares really well and competes really well in the international and global Synchrotron network. I will not want to say it is a market, it is really more a network where we do research and share results with one another and I think it is going really, really well.

Matt de Neef:

You touched before on the links that Synchrotron has not just in the faculty science, technology and engineering but also in humanities and specifically in archaeology and Dr. Mark Eccleston from the Archaeology Department is a good friend of the La Trobe Podcast series, and I believe the two of you have been doing some interesting research together. Would you mind telling us a little bit about what that research is and how you have been working together?

Peter Kappen:

Sure. This research that Mark and I are doing is looking at ancient Egyptian faiences or glazes. These materials were produced about 3,000 - 3,500 years ago in various parts of Egypt and the region and we are looking at specific materials from the side of Amarna which is in middle Egypt. The site was active only for a very short period of time so we know exactly that these particular faiences were produced in this space of time, and we are particularly interested in the source materials and the make up of these faiences, these glazes.

And I should say faiences or glazes are glass-like materials. They are not exactly like a fully fledged translucent glass but they have this glazy character to them and we are interested in how these materials were made. A lot is known about that and these glazes are usually made predominantly of silica, so picked up a little bit of sand somewhere in the deserts there is plenty of that then use a little bit of a flux, nitron or soda or part of a plant that is quite readily available. And then usually these glazes are beautifully blue or green or have other colours like reds and purples and the like. We are interested in the blues and greens. And the blues and greens are usually containing copper, which is widely accepted as to be the responsible colorant and what we want to know is what are the source materials -- what was the source material for the copper that was put into the glazes in the production and the making of the glazes.

There are various possibilities. The Egyptians could have used some minerals from known sources. They could have dug up a little bit of Malachite or Azurite or of minerals as such, put that into -- ground that into the fine powder and put that into the glaze. They could also have used something like corroded bronze or bronze scrap, after all we are talking about the Egyptian Bronze Age. So bronze which is an alloy of copper with a little bit of tin was readily available in Egypt.

So that could have been a source material or perhaps there were other sources that we are not quite aware of at this moment. So we are particularly interested in what are the copper sources that went into these Egyptian faiences and we are trying to answer these questions with the help of Synchrotron technology.

Matt de Neef:

So it seems like there is a lot of unanswered questions still in terms of this research. Has there been anything that you have been able to discover in the time that you have been doing the research with Dr. Eccleston?

Peter Kappen:

Yes. We have come a few steps closer to finding some answers. The Synchrotron technology has helped us to look at the faiences in their present state today. And what we can see from that is that the copper is not present as mineral in the faience as they are today. The copper has a structure which is very much disordered.

If you imagine atoms clinging together and these atoms are making up the faience and somewhere in this mix of atoms, silicon atoms, and oxygen atoms and lots of copper atoms which are responsible for the colour. We know that the atoms around the copper are not neatly arranged like Lego blocks when you pack them together, but they are much more disordered like grains of rice in a bag of rice. These grains are all over the place, they are just disordered. So we know that the copper is sitting in environment that are very much disordered.

So the atoms around the copper are not neatly stacked together we found that using different Synchrotron methods. It does not really exactly answer for us today whether minerals can be excluded as a source of copper but what we are doing at the moment is we are cooking some faience ourselves, that is we have made up some mixes from suspected recipes as they could have done it, we have made these faiences with -- heated these mixes up to 800 or 900 degrees C as you would do when you make faience.

And we have taken some of these materials with us to the Synchrotron in Hamburg as we have recorded the data on those faiences. I'm actually analyzing the data as we speak so at this moment in time today I do not have a fully fledged answer for you whether we can include or exclude certain production techniques or source materials, but we are getting closer to some answers.

And as always in research, really as you get closer to one answer you open up questions. For example, questions we want to investigate next relating to the firing temperatures of these faiences. Faiences are usually fired in something like a little kiln or some setup where you light a fire and you put your faience base mix into there, your little objects that you formed from a wet paste and then you fire them in there for a couple of hours.

And these fires that the Egyptians would have lit would have gone probably up to 750 - 800 - 900 degrees possibly and up to 1,000 degrees. We would have to ask Mark on the specifics there but what may be an interesting point may be that the exact temperature at which you fire these faiences may have an influence on the structure of the copper as we see it today. So we want to investigate faiences fired at different temperatures to see if we can see some subtle structural changes in the copper as we can observe it today.

We are also interested in the coloration of those faiences. Most of the faiences that we have produced in the lab turned out blue. Now, we know that there are a lot of green faiences out there as well and they are dedicated green that have not just aged over the millennia but they were made to be green.

In the literature you would find some suggestions about how they were made green and we want to investigate that a little bit further too to understand really better how blues and greens are made and whether the firing temperature has a distinct effect on either the coloration or perhaps the structure of the copper. So it is a little bit of a challenging task to unlock these ancient secrets because if you put it in a different fashion we can see the cake and we can sample the cake and now we try to reverse engineer the recipe.

Matt de Neef:

You will find the ingredients.

Peter Kappen:

Yes.

Matt de Neef:

A few weeks ago I spoke to a colleague of yours in physics, Dr. Andrew Peele, about the research he has been doing with Leann Tilley from biochemistry and he talked about the interesting challenges that come up when you are working with people from different disciplines. And now as you are being talking your physicist working with someone from archaeology, how have you found that process and what are the challenges working with someone from a completely different discipline?

Peter Kappen:

Whether it is archaeology or agriculture or ecology or anywhere, the general challenge is always a communication challenge, really. For example, I might meet with someone in archaeology with Mark and we start talking about the challenges that Mark would have had. So Mark says, "Yes, I'm working on Egyptian faiences and we are doing this and this and we are interested in all of that" and then there are some archaeological terms and how he describes the challenges and I might not be familiar with these terms then I will answer usually and say, "OK, I understand that you are doing this and this" and if I get it wrong then I get corrected.

And so after a few minutes, five to 10 minutes, we start to speak the same language. And once we are on the same level, we can actually confidently talk about how can a Synchrotron assist in answering some questions or addressing some challenges.

So overall, Synchrotron is a really tool to enable research or enable analysis that cannot be done in a laboratory setting. So this is really what we are usually looking for. We are trying to identify how a Synchrotron can benefit the laboratory-based research.

Matt de Neef:

Early in the year we saw a couple of students from St. Helena High School win the "Sleek Geeks" Eureka prize for Science Communication and as I understand you acted as a mentor for these students. How did you find that process?

Peter Kappen:

That was a great experience. I believe it was a great experience for the students but it was such a great experience from a mentor's point of view because these kids are really switched on. When we met for the first time it only took about a couple of hours for them to reach a first year physics level. We were talking about electromagnetic waves and they were coming up with ideas like photons, which are the particles of light, and these sorts of things. So it was really impressive how quickly they grasped the concepts that we are going to talk about and we are going to talk about x-rays, what you can do with x-rays, what x-rays are, and how x-rays were discovered and all of that.

So the students from St. Helena did a great job in grasping the core concepts of this project and coming up with a really clever way of illustrating how x-rays were actually discovered and that won them the Eureka Science Prize in the "Sleek Geeks" Category, so good on them, congratulations.

Matt de Neef:

And if you would like to leave a message about this or any other podcast in this series or suggest a possible podcast topic, you can get in touch with us at podcast@latrobe.edu.au. Dr. Peter Kappen, thanks so much for your time today.

Peter Kappen:

A pleasure to meet you. Thanks for the invitation.

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