Exploring caves for climate clues pAGE 14
Neil deGrasse tyson visits the lab pAGE 22
FLUX MAGAZINE Issue 10 editor’s note
Welcome to a brand new flux! Inside this issue, you’ll find stories of scientific discovery we hope inspire you to consider a career in science.
The lab’s intern program gives college students like Lorena Sanchez the opportunity to conduct research at the MagLab.
If you’re still in school — be it middle, high school or college — your biggest exposure to science may be your science classes. If so, you probably haven’t a clue what it’s like to work as a laboratory scientist. But guess what? There are plenty of ways you can discover what that’s like right here in the world-class Magnet Lab. All you have to do is a little detective work to learn what opportunities are here and how you can apply. You can start your investigation in this issue. If you’re in college, head to page 24. There you can read about the MagLab’s cool internships for college students and learn what two former interns had to say about the lab’s prestigious Research Experiences for Undergraduates program — which pays you to come learn and work here. One of the interns in “MagLab 101,” Lorena Sanchez, enjoyed the experience so much, she even returned to work part-time at the lab. If you’re a middle-school girl already daydreaming about summer, don’t miss the story on page 2. The SciGirls program is just the place for girls who want to discover new aspects of the world they live in. If that sounds like you, the 2014 program starts on July 14 — and the deadline to apply is March 28. More SciGirls stories, blogs and the necessary application forms can all be found on the MagLab’s website, www.magnet.fsu.edu. In between writing about the adventures of the SciGirls and this issue’s cover-story scientist, Darrel Tremaine, some of us in the MagLab’s Public Affairs Department also enjoyed an extra winter’s treat: a visit with astrophysicist Neil deGrasse Tyson. He dropped by the lab for a tour, and you don’t want to miss what he had to say — especially his insight on office chairs! Check out that story on page 22. Things change every day at the MagLab, so it shouldn’t surprise you to learn that we’re planning some changes for flux, too. You can stay in touch with all the things happening with flux and here at the MagLab, by liking our Facebook page and checking us out on Twitter.
— Editor-in-Chief, Kathleen Laufenberg
Contents Cover FeAtUre
14 Darrel and the Caves A MagLab researcher looks for clues about the Earth’s climate history inside cave formations.
07 Science Show & Tell Six MagLab scientists each share one object that represents what science means to them.
edUCAtion + oUtreACH
Behind the Scenes with the SciGirls SciGirls campers sit-in on an operation at the animal shelter.
MagLab’s Spider-Man Follows Nature’s Lead A MagLab scientist explores the potential of spidersilk.
Sodium Science Sodium MRI techniques point to better cancer treatments.
Q & A with Dr. Likai Song This MagLab biophysicist is working on an HIV vaccine.
24 Lab Life 101 What’s it like to be a MagLab intern?
At the Lab: Celebrity Scientist
Astrophysicist Neil deGrasse Tyson drops by the MagLab.
Last Look: HiPER Magnet It’s the Magnet Lab’s “Witches Hat” machine.
CONNECT WITH US Find us on Facebook, Twitter & YouTube or visit magnet.fsu.edu
26 Bubble Trouble A problem that stumped scientists for months finds a simple solution after reframing the issue.
FLUX MAGAZINE Issue 10 FLUX MAGAZINE
Issue 10 / WINTER 2014
education + outreach
Magnet Lab Director Gregory S. Boebinger Magnet Lab Deputy Director Eric Palm Director of Public Affairs Kristin Roberts Flux Editor Kathleen Laufenberg Graphic Designer Lizette Vernon Photographers Dave Barfield Kathleen Laufenberg
Flux is a publication dedicated to exploring the research, magnet technology and science outreach conducted at the National High Magnetic Field Laboratory’s three campuses in Florida and New Mexico. The Magnet Lab is a national user facility that provides state of the art research resources for magnet-related research in all areas of science and engineering. The Magnet Lab is supported by the National Science Foundation and the state of Florida. It is operated by Florida State University, the University of Florida and Los Alamos National Laboratory.
Behind the scenes with SciGirls
A visit to the Tallahassee animal shelter
Kristin Roberts at: u Contact
BY KATHLEEN LAUFENBERG
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mma Macedo is only 11, but she learned some grown-up lessons when her SciGirls group visited the Tallahassee animal shelter in July. “This place is so big,” Emma said, as she stood in the shelter’s bustling lobby beside a caged rabbit. “I thought they just would have a couple of kennels, but they have a lot of pets here, and a lot of them still need homes.”
SciGirls is a two-week, hands-on summer camp for girls in middle school run by the MagLab and WFSU. The program, launched in 2006, gets girls excited about careers in science. All of the 35 girls in the 2013 program toured most of the 12,500-square-foot animal shelter and saw some of the nearly 400 animals housed there. They learned that nearly half of the animals that came into the shelter the year
FLUX MAGAZINE Issue 10
“You get to do stuff with SciGirls that you don’t ever normally get to do, like see this surgery.” — DAKOTA POITEVINT, SCIGIRLS COUNSELOR
before were euthanized, many because no one wanted them. But while the SciGirls learned some hard truths during their visit, they also learned what they could do to make a difference, particularly spaying and neutering their own pets. The girls were excited to go behind the scenes at the shelter, too. They got to watch veterinarian Rachel Barton spay a puppy — and two girls even volunteered to help. One girl shaved the little female pup’s belly/spay area. After the surgery — which went very well — was completed, another volunteered to clean the area. “I was a little shaky at first,” Caroline Kynoch, 11, said of watching the surgery. She was pleased, she added, that all of her family’s three cats have already been either spayed or neutered, so they would not be adding to Tallahassee’s unwanted pet crisis. In addition to going behind the scenes at the animal shelter, the SciGirls visited a forensics lab at the Tallahassee Police Department, a wolf sanctuary in Chipley, a marine quarry, local sinkholes and Wakulla Springs State Park. Because she had so much fun the first time, SciGirls counselor Dakota Poitevint
A SciGirls camper and an animal shelter worker shave a female puppy’s belly to prepare her for surgery.
returned for a second year as a counselor. She also attended as a camper twice. “You get to do stuff with SciGirls that you don’t ever normally get to do, like see this surgery,” Dakota, 17, said. “The animal shelter is always one of my most favorites. It really shows you how many animals don’t have owners and how many animals are here, and how low the adoption rate is.” Working with SciGirls is also a favorite experience for the teachers who accompany them. “It’s every teacher’s dream position,” said Susan Goracke, a fifth-grade teacher at Leon County’s Canopy Oaks Elementary. “These girls are thirsty and hungry for learning. They don’t complain about writing — they ask for more paper for their journals. This is just so refreshing, it really gets me ready to go back to school.” The animal shelter deserves special credit for making the day a success, said Roxanne Hughes, director of the MagLab’s educational outreach.
“Kim Kelling-Engstrom (WFSU’s education director) and I can’t thank Rachel Barton enough for the work she does for this program,” she said. “Every year, she plans this day with her staff, and it’s always a favorite. She does a wonderful job, as do all our scientist volunteers, explaining to the girls how to prepare for a career in science, technology, engineering and math.”
STEM PROGRAMS FOR GIRLS
• The MagLab & WFSU hold SciGirls camps in Tallahassee every summer. For more info please visit: www.wfsu.org/scigirls. • Search for other SciGirls camps and similar programs for girls across the U.S. by visiting: www.ngcproject.org/programs.
FLUX MAGAZINE Issue 10
Eden Steven uses spider silk found around the MagLab to create a new, superstrong material.
MagLab’s Spider-Man Follows Nature’s Lead By coating a spider’s silk threads with special nanoparticles, physicist Eden Steven discovers a promising material — and draws the scientific world into its web. BY KATHLEEN LAUFENBERG
arvel Comics, move over. Physicist Eden Steven — aka, the MagLab’s Spider-Man — is coming through. Steven’s innovative experiments with spider silk and a high-tech material sparked a perfect storm of interest in the fall of 2013 — as well as talk of a potential super material. Steven, 29, was caught in the international spotlight after Nature Communications published the results of his unique research experiments. He coated strands of spider silk — carefully removed from spider webs right outside his lab — with carbon nanotubes, or microscopic rolled-up sheets of an extremely lightweight yet tougher-thansteel form of carbon called graphene. After Nature
Communications broke the news, Steven’s research recipe triggered headlines around the world, from Los Angeles to India.
A Simple Idea
While his spider-silk experiments were clearly inventive and original, they were also environmentally friendly and surprisingly simple — so simple, in fact, that it had never occurred to anyone that such a method might work. “We started out with a simple idea: Can we use spider silk as a wire?” Steven says. “If we understand basic science and how nature works, all we need to do is find a way to harness it. If we can find a smart way to harness it,
FLUX MAGAZINE Issue 10 then we can use it to create a new, cleaner technology.” Steven — the lead investigator on the Nature paper “Carbon nanotubes on a spider silk scaffold” — collaborated with six other scientists, including Florida State University Physics Department Chair James Brooks and Fulbright scholar and Iraqi physicist Wasan Saleh. Saleh worked with Steven and Brooks at the MagLab in the summer of 2011; she was one of 10 Iraqi Fulbright scholars visiting Florida State University, and the only woman in the group. The scientists’ eco-friendly recipe revolved around three main ingredients. Two are quite familiar — spider silk and water — while the third, carbon nanotubes, is hi-tech. A one-atom thick nanotube is an infinitesimally tiny tube: Its diameter is at least 10,000 times smaller than a strand of human hair! And when things get that microscopically minute, physicists know that they act very strangely. Researchers worldwide are intrigued by the properties of carbon nanotubes, particularly their amazing strength and ability to conduct electricity and heat.
MagLab physicist Eden Steven.
Keeping with his theme of simplicity, Steven gathered the spider silk himself, hiking around the MagLab and using a stick to gather a small part of a spider’s web. He respects the spiders and is careful not to destroy their webs or hurt the insects. “I don’t want to get too much: that would destroy it,” he says of the arachnid’s web. “It is a creature that inspires me a lot. How can such a creature make such a special fiber that no one up to now can recreate? So many issues.” Once he has some spider’s silk, the
FLUX MAGAZINE Issue 10
A container holds the ingredients of Steven’s special spider wire recipe.
next step is to adhere the powdery carbon nanotubes to it. Steven discovered that just a drop of water worked best. His unassuming recipe and dazzling results drew the attention of media that included Discovery News, New Scientist, Nature Middle East, Global Post, Materials 360, The Economic Times, Z News, Los Angeles Times, The Hindu and more. “It turns out that this high-grade, remarkable material has many functions,” Steven says of the carbon nanotube-coated silk. “It can be used as a humidity sensor, a strain sensor, an actuator (a device that acts as an artificial muscle, for lifting weights etc.) and as an electrical wire.” His “spider wire” is stretchy, super strong and can shrink and grow with humidity, too — just as spider’s web does. To determine if the high-tech wire would also conduct electricity when bent, Steven
formed it into the acronym FSU — and it worked! The actual letters were small enough to fit on a man’s wedding band. Steven was especially interested in experimenting with the possibilities of spider wire because it’s an eco-friendly material. Many of today’s electronic devices contain toxic elements and complex, non-biodegradable plastics that end up as pollution in our environment. But his spider wire is able to handle changes in humidity without complicated treatments and chemical additives.
partment of Chemistry and Biochemistry; Rufina G. Alamo, with the FAMU-FSU Department of Chemical and Biomedical Engineering; Victor Lebedev, with the Institute of Materials Science of Barcelona; and Vladimir Laukhin, with the Catalan Institution for Research and Advanced Studies (ICREA) in Barcelona. Fostering such diverse scientific alliances is actually a big part of what makes the MagLab such a dynamic workplace. “The Magnet Lab and its sister materials centers at FSU provide an interdisciplinary environment that attracts the expertise of scientists from across the entire university and around the world to come here to do collaborative science,” says MagLab physicist Brooks. “In such an environment the scientific imagination can run wild in unexpected directions. “ Steven’s work was supported by the National Science Foundation, the Department of Energy and the State of Florida. MagLab scientist Yi-Feng Su and Xixi Jia assisted with the transmission electron microscopy study; MagLab postdoctoral associate Jin Gyu Park assisted in the tensile measurement and Raman spectroscopy study; and spectroscopy facilities were provided by FSU’s High-Performance Materials Institute.
Steven worked with a variety of scientists across the globe to test his spider wire. In addition to Saleh, who teaches at the University of Baghdad, the other research collaborators on the paper were: Steve F.A. Acquah, with the FSU’s De-
Using his spider wire, Eden Steven spelled out the acronym FSU to see if the wires would still conduct electricity when bent. They did!
FLUX MAGAZINE Issue 10 PHoto essAY
Six MagLab staffers share a treasured object that embodies their passion for science. BY KRISTEN COYNE with PHOTOS BY DAVE BARFIELD
cience is everywhere, from your coffee cup to your computer, from your car to your sunglasses. In every object, there’s a story — about physics, chemistry, biology or other science. For the curious mind, these everyday items can inspire wonder, passion and endless questions about how the world works. For the researchers and technicians in the stories that follow, those questions paved a unique path to science and, ultimately, to the MagLab.
1. 2. 3. 4. 5. 6.
David Graf’s experimental sample Steve McGill’s smart phone Hans van Tol’s bicycle wheel Nicole Walsh’s superconducting cable Shermane Benjamin’s world globe James Brooks’ harmonic oscillator
FLUX MAGAZINE Issue 10
“It’s like opening a present on Christmas morning.”
Science is a surprise David Graf
David Graf came to the MagLab 14 years ago as a student and never left. As a staff scientist, he helps visiting scientists prepare and conduct experiments in the lab’s powerful magnets. He enjoyed many white Christmases as a kid in upstate New York. But these days, as an avid runner, he much prefers Tallahassee’s gentler climes.
“People want to protect their samples when they ship them to us, so we end up with two or three cardboard boxes within boxes with Styrofoam and packing material. In the center, we end up with a little, maybe 1-inch-square box with samples inside. And once you open that box, you’ll have even smaller samples, which are sometimes the size of a head of a pin. “It’s like opening a present on Christmas morning. You see new samples and your first thought is: What am I going to see with these samples? Will my techniques show new science in these materials? Or am I going to have to try something new? “In our case, the samples are usually
single crystals of material. We’re interested in understanding the properties of it better. Measuring the sample is the experiment. The first thing we do is cool down the sample, usually to just a little bit above absolute zero, to see what happens. Then we ramp up the magnetic field. “It’s like when you’re watching a good, suspenseful movie and you want to know what happens at the end, but the process of getting to the end is also interesting. There are hours of work in preparing the sample. And then there is that initial five, 10, 20 minutes of ramping the field where you see if the work pays off. It’s exciting the first time you see something. Then you think: Well, what can I do next?”
FLUX MAGAZINE Issue 10
“It’s been an inspiration to see the advances this piece of technology has gone through as a result of scientists.”
Steve McGill uses optical methods to study condensed matter systems. He specializes in using pulsed lasers to measure magnetic and electronic properties of materials. Originally from suburban Philadelphia, McGill enjoys swimming and is an Eagle Scout.
Science pushes boundaries “This item has been on the journey with me all the way from high school to the present day. I’ve seen it change as I myself have changed. “After I started driving, I was spending a lot of time on the road and my parents were concerned. It turned out you could get one of these things you could put in your car, and as you were driving along you could make calls. Actually, it was a huge bag, a full-size handset, a big coax cable and big antenna: This thing was a monster! As time went on, I got one that was about the size of a brick, but — again — all you could do with it was make calls.
“It’s been an inspiration to see the advances this piece of technology has gone through as a result of scientists who have been able to make materials and miniaturize things, make data storage smaller, make new, more power-efficient materials, longer-lasting batteries. The imagination is the limit. “There are different manifestations of the same story. Something’s always changing. That fuels the interest within me to do science, to always see what’s around the next corner. The phone is an example of engineering pushing our capabilities for gadgetry. In science we try to do the same thing — by pushing the boundaries of the unknown.”
FLUX MAGAZINE Issue 10
“Physics and science give you a way to solve the puzzle of nature and what is around you.”
HANS VAN TOL
Originally from the Netherlands, Johan “Hans” van Tol studied and worked in chemistry and physics in Europe for many years before coming to the MagLab in 1998. He is interested in the role of electron spins in the magnetic and optical properties of various materials, and in how they impact bioreactions like photosynthesis. A bike commuter, he covers about 4,000 miles a year.
Science solves puzzles “I am not only a scientist, I am also a cyclist. So the bicycle wheel is symbolic for me, as well as something that made me interested in science. If you spin the wheel, the wheel will stay in kind of the same position. As a kid I was intrigued why this was, why you have these funny forces. You can see that if you spin the wheel and try to hold it and change the position, it resists. By understanding something like this, you can start to understand a lot of other complicated things.” “For me science is a question of solving this puzzle — understanding
why the wheel is not falling to the floor, and how you can use this. In this case it’s kind of an angular momentum; these kinds of things play a role on the quantum scale of molecules and atoms, and that is the subject of what I’m looking for at the moment. “Physics and science give you a way to solve the puzzle of nature and what is around you, and why materials behave like they behave. And this is one of the reasons I went into science — just to try to understand the world around you and perhaps improve it also a little bit.”
FLUX MAGAZINE Issue 10
“It’s really interesting to actually do, to be active in something that could potentially make a difference.”
Nicole started out at the MagLab as a receptionist, but soon talked her way into a job in the lab’s resistive magnet shop, where she spent her days painstakingly stacking magnet parts called Bitter plates and learning about magnet technology. She also discovered a love for science and engineering, and now studies mechanical engineering while working at the lab part-time, building superconducting magnets out of materials like niobium tin and niobium titanium.
Science is hands-on “This cable-in-conduit is a superconducting cable that has no resistance when you pass current through it. With resistance you lose energy; with this you’re not losing any energy. “This demonstrates what I do on a daily basis. This might seem like it’s just a piece of tube with cable in it, but it started off with knowing what kind of material you wanted to have, what shape of tube you want. This is the end product of a whole bunch of collaboration, a whole bunch of work. This is our pride and joy. “Starting out with a drawing, magnet technicians make the parts and make
sure they fit. They have to know how stuff moves and works and pulls against each other, and that comes with experience. I love the theory, but it’s also really interesting to actually do, to be active in something that could potentially make a difference. “At the MagLab, I fell in love with this engineering thing — this collaboration between minds, this ability to have a concept all the way down to a design, and then being able to fabricate the design, being able to grab it and be a part of it. It’s amazing, it really is.”
FLUX MAGAZINE Issue 10
“Just like art and music are considered universal languages, I think science in its own right is a universal language.”
Shermane Benjamin was preparing for a career as a pianist before his love of math and science steered him toward physics. Now a Ph.D. candidate at Florida State University and a graduate research assistant at the MagLab, Benjamin still steals a little time for music on his pennywhistle.
Science is global “This globe has two meanings — one a more personal meaning, one a wider meaning. When I was in high school, my teacher asked us, if someone was at the equator and the other person was at one of the poles, are they moving at different speeds? And my naïve answer was: They’re moving at the same speed. But then she made clear to us that there was a distinction between angular velocity and linear velocity. She went on the board, proved it mathematically. That really caught my attention — like, Wow, this is real! “That right there really pushed me into the science route. I liked it because it was these different things coming
together and now making sense, bringing light to something that I thought was one way, but which was really the other way. “And also I think it has a global meaning. Just like art and music are considered universal languages, I think science in its own right is a universal language. Science basically touches everyone. Everyone experiences the sun shining, everyone is on the globe rotating, everyone experiences these scientific things. Everyone is curious. So we may not all speak exactly the same perfect language and understand each other in that sense, but scientifically we all have that commonality between us.”
FLUX MAGAZINE Issue 10
“It makes our world stable; it keeps it from falling apart.”
Over the decades, James Brooks has worked in many areas of experimental, low-temperature and high magnetic field physics. A fellow of the American Physical Society, he pioneered the use of dilution refrigerators in high-field resistive magnets and holds the record for doing an experiment in the largest steady state magnetic field (47.8 tesla). Brooks also devotes time to educational outreach and eschews golf in favor of cast netting for mullet near his Gulf Coast home.
Science is about coming home “My object is a fishing weight attached to a rubber band: It’s a harmonic oscillator, which can pretty much model most of the natural world. It’s something that has inertia and mass, and is connected to some kind of a force. It represents something that has what’s called a restoring force, and this keeps this object from moving too far from its home.” “If I pull the weight out a little and let it go, it goes back and forth like a pendulum; the mass is always trying to get back to the center. This simple model can explain mechanics, light, atomic physics, music and many other things in the natural world. It can explain how mat-
ter stores energy, and is responsible for how matter can emit or absorb energy, as well. Due to its beautiful simplicity, it allows us to understand how the universe works and hopefully how to exploit this knowledge for the benefit of society. “When I was a freshman in a mechanics class, it’s something that just occurred to me — or perhaps my professor mentioned it — and I thought that was really cool. Maybe it’s not beautiful; maybe it’s magic that things work the way they do. When the wind blows the tree, the tree will bend; when the wind stops, the tree goes back and it’s straight again. It makes our world stable; it keeps it from falling apart.”
FLUX MAGAZINE Issue 10
See that smile? That will disappear when MagLab scientist Darrel Tremaine begins his descent into Dragonâ€™s Tooth cave, where passageways are so tight he has had to remove his helmet and turn his head sideways just to squeeze through.
FLUX MAGAZINE Issue 10 Cover Feature
Darrel and the Caves To learn about our planet’s paleoclimate, a MagLab scientist goes underground BY KATHLEEN LAUFENBERG
t’s spooky inside the Dragon’s Tooth, an ancient cave in Marianna, Fla. It’s so dark you can’t see your own hands, and the air is ripe with earthy decay. It’s eerily quiet, too — except for the breathing of 33-year-old Darrel Tremaine. Tremaine, a MagLab scientist, wants to understand what the climate was like in North Florida thousands of years ago. He’s especially interested in prehistoric rain patterns — info that could help predict future rainfall. So for more than two years, he and several other Florida State University graduate students have regularly visited the Tooth, collecting data from natu-
ral earth formations called stalagmites that grow on the cave’s floor. Inside them is a treasure chest of climate information. “We want to be able to predict what the rainfall patterns are going to look like in North Florida over the next 10, 50 or 100 years,” he says. “Our work with these stalagmites is really just one small piece of a much larger climate puzzle.”
The instruments he uses to decipher this climate puzzle are found at the MagLab, and they allow him to explore in a different way. By measuring the minute amounts of certain chemicals locked inside the stalagmites, he can discover what the environment was like.
While stalagmites grow up from the floor, similar formations called stalactites also form on the ceiling. Stalagmites and stalactites can resemble boney fingers poking into the cavern or assume much thicker forms. A famous stalagmite at Marianna Caverns State Park resembles a wedding cake. A towering, 8-foot-tall stalagmite in Dragon’s Tooth resembles a giant tooth (hence the cave’s name). No matter their shape, though, most of the cave’s rock-hard stalagmites are thousands of years old. And trapped inside them are trace elements and growth patterns that reveal what the weather was like in ancient times. “If you know how to read it, a stalagmite is just like a weather book,” says Tremaine, a doctoral student in chemical oceanography. “There’s all kinds of information in there, but you need to know how to retrieve it.” Rain creates these earth sculptures. As rainwater trickles through the earth, it dissolves the calcium carbonate in limestone. The calcium-rich water
FLUX MAGAZINE Issue 10 planet’s environmental history. And while the same climate information is found in both stalagmites and stalactites, researchers say stalagmites reliably contain more detailed data. That’s why Tremaine, like many scientists, focuses his research exclusively on stalagmites.
The cave breathes
“Once we have an idea of what’s going on inside the cave, how the cave breathes in and out and its water chemistry, then we have an idea of how to interpret the records that are locked up inside the stalagmites.” — DARREL TREMAINE, maglab grad student
drips into underground caves. The dissolved calcium builds up on the ceiling where it’s dripping from, and on the floor beneath the drip. Over eons, the stalagmites and stalactites grow, forming new rings (just as trees do) with each cycle of growth. Because they grow so slowly — adding perhaps a ring no thicker than a fingernail each year — they contain incredibly detailed chemical records of the
In order to explore these caves, though, Tremaine has to squirm through long, muddy passageways — called flatteners — that are barely a foot tall. It’s not for the faint of heart. “I’ve been through passages so tight I had to breathe out to squeeze through,” the 155-pound Tremaine says. “I’ve had to take off my helmet and turn my head sideways just to snake through … I’m definitely braver than I was before doing this.” But there’s beauty in caving, too. Once Tremaine slithers through the Tooth’s longest passage — a 20-foot flattener — he’s in the Dragon’s Belly. Inside this 20-foot tall, 100-foot wide room, he can stand up, stretch and use his bright, helmet-mounted lights to scan the Belly’s impressive gallery of stalagmites. In order to understand the weather clues locked inside these mineralized crystals, however, Tremaine also needs to understand the environment they grew in. “It’s sort of like, if you want to analyze a child, you have to go to the child’s house and figure out what kind of environment he grew up in,” he says. “Once we have an idea of what’s going on inside the cave, how the cave breathes in and out and its water chemistry, then we have an idea of how to interpret the records that are locked up inside the stalagmites.” So inside the Tooth, he’s set up several small, battery-powered machines to track how the cave breathes. He monitors the
cave’s carbon dioxide and radon levels, its temperature and humidity levels, and its barometric pressure and airflow velocity and direction. He also records the slow drip-drip-drip that forms the stalagmites. “You measure as many things as you can and try to understand the changing drip chemistry, and the changing stalagmite chemistry, in terms of changing rainfall and changing ventilation,” he says. “Eventually, you do start to see patterns develop.” Because the caves are pin-drop quiet, Tremaine sometimes calls his research “Zen science.” He’s even found a special meditation spot near an opening in one of the caves: At dusk, the light glows there in a mesmerizing way.
Back at the Lab
After more than a year of collecting cave data, Tremaine was ready to begin examining the stalagmites themselves. In order to do that, he had to remove them. It’s illegal to remove these prehistoric relics — which are beautiful eye candy in themselves — from public lands. Although scientists with legitimate goals can get permits to do so, Tremaine didn’t need any. The stalagmites he wanted were on privately owned land, and the owner gave him the necessary permission. Tremaine chose to examine two: One is about 4,000 years old and 5 inches tall; the other, 50,000 years old and 10 inches tall. Once removed, he examined them in special labs in the MagLab’s geochemistry department. He uses the geochem “clean labs,” which require you to take off your shoes or don special booties, wear a lab coat and even a hair net. The hypersensitive spectrometer machines inside these labs can detect barely-there traces of chemicals, and you don’t want to contami-
FLUX MAGAZINE Issue 10 libraries of North Florida’s climate history. Preliminary data from one of the stalagmites also indicates that 2,200 years ago, something drastically changed, either in the weather, in the cave itself or on the land directly above the cave. Exactly what happened, though, remains a mystery until more data can be collected. “To learn what our past was, we must look into nature’s archives, such as these stalagmites,” Misra says. “It’s very important work because we need a continental climate record.”
back at the lab, Darrel uses a spectrometer to analyze the trace elements present in his stalagmite samples.
nate your samples with dust from your shoes, hair, hands or elsewhere. Tremaine carefully drills into places along each stalagmite and removes powdery samples. He analyzes these samples for infinitesimally tiny amounts of carbon and oxygen, as well as magnesium, calcium, barium, strontium, lithium and uranium. These trace elements are clues to the temperature inside the cave when the growth ring formed. Using this data, he can determine whether the weather was cold, warm or hot when the ring formed. And he can deduce what type of vegetation was growing on the earth above the stalagmite. But teasing out the trace elements is also an art. He’s looking for a trace of, say, lithium in the range of one part per billion. “That’s a very tricky measurement,” says Sambuddha Misra, a former MagLab scientist doing his postdoctoral work in
chemical oceanography at the University of Cambridge in England. Misra helped Tremaine learn how to use the MagLab spectrometers, and he also explained to him why even talking to another scientist while working with some of the spectrometers can alter the readings. “Your spit has a lot of sodium in it, and when you blink you give off potassium, and these machines are sensitive to one part per trillion,” Misra says. To take such precise measurements, he adds, demands a special type of attention. “You work on a flow bench, and you work with your hands away from your body. It’s essentially a ritual, and you try to make every step as perfect as possible.” Two years into his data collection, Tremaine discovered that both of his stalagmites grew continuously during the last 4,000 years — which makes them perfect
This bisected stalagmite is made of crystalized rings of calcium that were formed over a period of 50,000 years.
FLUX MAGAZINE Issue 10
MagLab scientist Victor Schepkin points to a sodium MRI scan of a brain tumor in a rat (the white mass beind the eyes). Tumors are easy to spot because of their higher concentrations of sodium. Sodium MRI gives scientists lots of useful information about cancer, including how it forms and if it is drug-resistant.
Sodium Science: Worth its Salt for Cancer Research BY KRISTIN ROBERTS
We all know that cancer is serious, but did you know that cancer is responsible for more than 7.6 million deaths a year worldwide and 1,500 a day in the U.S.? New drugs and treatment strategies are helping transform cancer victims into cancer survivors, but more than 1.6 million new cancer cases are expected to be diagnosed in the U.S. this year alone. Cancer cells are different from normal, healthy cells in your body. In a normal cell, if DNA is damaged, the cell repairs itself or dies. In cancer cells, though, damaged DNA is not repaired and the cell doesn’t die as it should. Instead, these damaged cells grow uncontrollably into abnormal cells that then can also attack other tissues. Magnetic Resonance Imaging, or MRI, is a key tool in cancer detection and treatment planning. With the help of strong magnets, MRI scanners take pictures of your insides by mapping the water in your tissues. These scans help doctors locate abnormal growths in the body that could be cancer. MRI scans can also help doctors determine if a tumor is benign or malignant and can even show physicians whether cancer cells have spread to a different part of the body.
he MagLab’s Sodium Sleuth, scholarscientist Victor Schepkin, has explored World’s Strongest MRI Scientists measure magnetic field sodium in crystals, hearts and now strength in units called tesla. A refrigbrains, trying to solve some of our world’s big- erator magnet that holds your appointreminder card is about 0.03 tesla. gest medical mysteries. This time, his work ment Most MRI machines used by physicians to understand how sodium relates to tumor or in hospitals are between 1 and 3 tesla. the National High Magnetic resistance could lead to new, more effective FieldAtLaboratory, however, a 21.1 tesla cancer treatments. MRI magnet produces images that
FLUX MAGAZINE Issue 10 are much more detailed than those you could get with a standard MRI. Known as the world’s strongest MRI machine, this magnet allows researchers to isolate atoms other than water, such as sodium, in the body of small living animals such as birds, rats, hamsters or insects.
Sodium: So what?
Why would scientists want to look at sodium in the body, and what does sodium have to do with cancer research? Sodium is actually a critical component of your body’s health. Acting as both an electrolyte and a mineral, sodium helps maintain a balance between water and electrolytes in the body. Sodium is also important in nerve and muscle functions and helps in transporting chemicals to and from cells. But sodium, as it turns out, may also hold the key to cracking cancer cells’ strength, says Schepkin, who has conducted numerous experiments in this area. His recent work with co-collaborator and neuroscience expert Cathy Levenson, from Florida State University’s College of Medicine, offers powerful new information on cancer that may someday lead to new, more effective and successful cancer treatment strategies. Cancer cells aren’t just deadly, they are also quite clever, able to divide, mutate and evolve to stay alive. “After chemotherapy,” Levenson says, “cancer cells learn how to evade the drugs and create a resistance, not just to the original chemotherapy, but to other treatment options as well.” This drug-dodging can leave patients feeling helpless and doctors scrambling to find new treatment solutions. What doctors really need, Levenson says, is a non-invasive way to see whether a tumor is resistant to different chemotherapy op-
tions before they treat the cancer. Enter the world’s strongest MRI machine, the MagLab’s 21.1 tesla. With the high magnetic fields available at the MagLab — approximately 50 times more sensitive than a traditional MRI — Schepkin and Levenson were able to visualize sodium in cancer cells from a rat’s brain to see when a tumor has become resistant to chemotherapy. They discovered that cancerous brain cells with low sodium levels indicate stronger, more resistant tumors, while cells comprised of more sodium are less resistant and could be treated efficiently and with the use of fewer drugs.
Scientists Victor Schepkin and Cathy Levenson stand in front of the lab’s 21.1 tesla, 900 megahertz magnet, a key tool in their MRI research.
Diffusing the cancer situation
Schepkin also uses a special technique called diffusion MRI to learn more about cancer cells. Diffusion MRI doesn’t just track where water is in the body, but also looks at the movement of that water. When combined with sodium imaging, diffusion MRI is able to show researchers whether chemotherapy is working in a rat with brain cancer much sooner than is currently possible for human cancer patients. Patients must typically wait weeks or months to see if cancer treatment is having an effect on their tumors. The MagLab’s powerful MRI, though, can reveal if a tumor cell is shrinking in just hours by identifying the change in sodium levels in the cancer cell. “Before cancer cells die, we can see on the MRI scans that these cells first lose sodium and then, more water flows into the tumor cell,” Schepkin says. These two MRI processes — sodium MRI and diffusion MRI — could one day work in concert to offer two unique ways for physicians to analyze a tumor and decide how to best treat that specific case of cancer. And perhaps even more importantly, this research could be the key to an entirely new way of killing cancer cells. “This is exciting,” says Schepkin, “because it means we may be able to destroy cancer cells in a different way than we did before.” By forcing a sodium imbalance in a cancerous cell, scientists may be able to destroy cancer cells without the use of any chemotherapy at all. Cancer treatment without the chemotherapy side effects? Now that would really be worth its salt!
FLUX MAGAZINE Issue 10 Scientist spotlight
Q & A with Dr. Likai Song BY KATHLEEN LAUFENBERG Dr. Likai Song is a physicist as well as a medical doctor who aptly describes himself as a biophysicist, i.e., a scientist who uses methods of physics to discover how biological systems work. He was born in China and grew up in Beijing. He received his training in internal medicine and cardiology at the Beijing 301 Hospital and studied biophysics at Florida State University. After completing his doctorate at FSU in 2005, he worked as a research scientist at the Dana Farber Cancer Institute, an affiliate of the Harvard Medical School, in Boston. In 2010, he and his wife and daughter moved back to Florida. It was the magnets that drew him to Tallahassee. At the Boston cancer center, he’d begun collaboratively working with a pioneering group of doctors and researchers whose goal is to develop a vaccine for HIV (Human Immunodeficiency Virus). HIV infects the cells of a person’s immune system and destroys or impairs their function. According to World Health Organization estimates, more than 35 million people were living with HIV at the end of 2012. That same year, about 2.3 million people also became newly infected and 1.6 million died of AIDS-related causes.
In order to create a vaccine or drug for this virus, Dr. Song uses the lab’s magnets to probe a surface protein of the HIV virus called “gp41.” His studies focus on how the virus, with the help of this protein, enters through a healthy cell’s membrane to infect it. His goal is to learn how to prevent an HIV infection by targeting the gp41 protein using a vaccine or drug. Since moving to Tallahassee, Dr. Song and his wife have also had another daughter. How do you describe your work? “As a biophysicist, I work in an interdisciplinary area that allows me to use both my knowledge of physics and biology. I use physical tools like EPR (Electron Paramagnetic Resonance) to study the structure of molecules in the human body. “The basic nature of science is solving problems, so as a scientist, I am a problem solver. Some days, you have to figure out if you prepared your sample correctly, or if the machine is behaving as it should. That’s not unusual.” Did you always want to be a doctor? “I didn’t actually know what I wanted to do when I was kid — but I knew what I was interested in. In high school, I was
“Follow your true interests and try to find out what you are really good at. Then use this information to decide your path.”
FLUX MAGAZINE Issue 10 really good at math and physics, and I was also exposed to some very good Chinese role models who were physicists. So I always knew I was interested in physics and science, but also in biology and medicine.” When he went to college though, he had to decide on a direction. He chose medicine. How did you make the jump from medicine to physics? “People always ask me that question! People don’t understand how I can make such a jump, and I know it does seem like a big jump from there to what I do now. But actually for me, it seems all-natural, because I was always interested in both. Even after I finished my medical degree and I became a doctor, I still had that interest in basic science such as biology and physics. Being a biophysicist to solve biomedical problems seems to be a good fit for me. “As a doctor, to treat diseases, you do that in a clinic. You see actual patients, and you help individuals. But if you really want to cure a disease that affects many people, then you have to do basic research.” What happened to bring you to the MagLab? “In Boston, at Harvard, I developed my interests and my projects in HIV research. What I was using to do my research, my main tool and method of inquiry, is actually EPR (Electron Paramagnetic Resonance). And the EPR facility in Boston is not comparable to the EPR facility here at the MagLab. This is the best place. We have world-class magnets and instruments at the Maglab. This year, we built a new EPR machine, the HiPER machine, a powerful instrument that will benefit my research and the research of
scientists who visit the lab.” (See more about HiPER on page 29.) What kind of research are you doing? “I am interested in using EPR and other methods to study the structure and functions of proteins in the human body. This area of research is also called structural biology. Structural biology captures the images of life at molecular and atomic levels. Structural biologists use various physical tools to determine the molecular details of proteins and DNAs, such as x-ray, magnetic resonance, electron microscopy, etc. “One of my current projects is to determine the structure and role of an HIV surface protein, gp41, in virus infection. It has been widely accepted that HIV viruses enter into human T cells (white blood cells that play various important roles in the human immune system) via cell-to-cell membrane fusion. Gp41 plays a key role during this process. Interestingly, antiHIV antibodies can inhibit gp41 function, and thereby prevent HIV infection. A better understanding of gp41 function, and how antibodies disrupt its function, would help scientists to design a vaccine or treatment for HIV.” Can you explain your group’s approach to creating an HIV vaccine? “Scientists have been trying to make an HIV vaccine for the last 20 to 30 years, and they’ve tried all kinds of different methods, including using HIV proteins, peptides, genes, etc. So far, no successful vaccine strategy has been found. “I am working on a collaborative project, along with several other research groups within the U.S. My collaborators include immunologists, clinicians and structural biologists with a common goal
to study the structural details of HIV surface protein gp41, and develop a vaccine based on the structural information. My group is using EPR to study the structure of gp41 sitting on the viral membrane surface, and how anti-HIV antibodies interact with gp41, inhibit gp41 function and prevent virus infection.” As with other vaccines, Dr. Song’s group is creating a vaccine that “mimics part of the virus or bacteria so that the human immune system can recognize the vaccine and develop some antibodies against it. Hopefully, those generated antibodies can also cure the virus. “We are trying to study the basic structure of the surface protein of HIV, and then develop an optimized immune agent so the human body recognizes it as a native HIV virus and develops antibodies to cure HIV.” How close are you to creating an HIV vaccine? “We’re in the middle of the journey, I would say, because some of our results are very promising. A study published in the New England Journal of Medicine in 2012 also showed some promising data of clinical trials conducted in Thailand. But it is still a long way to go to develop a safe and effective vaccine. I think we are getting closer and closer.” Do you have any advice for young people who are still trying to determine their future careers? “Follow your true interests and try to find out what you are really good at. Then use this information to decide your path.”
FLUX MAGAZINE Issue 10 AT THE LAB
At the Lab: Celebrity Scientist Neil deGrasse Tyson When the New York astrophysicist visited the lab, his tour included stops at the magnet shop, DC control room, 45 tesla and 900 megahertz — as well as an impromptu furniture critique and a suggestion for a MagLab sound bite. BY KATHLEEN LAUFENBERG
Q: When is a chair more than a chair? A: When astrophysicist Neil deGrasse Tyson is in the house. One of the most recognized physicists on the planet, Tyson visited Florida State University in November and toured the MagLab, where he learned about magnet making, surveyed the Direct Current wing, held court on what constitutes a good office chair and offered tips for talking to the general public about what the lab does. “You do cool stuff with matter,” said Tyson, the director of the Hayden Planetarium in New York City. “That’s your sound clip.” Acting as his tour guide was MagLab director Greg Boebinger, who took Tyson to the top of the world-record 45 tesla (T) magnet, the overlook of the 900 megahertz (MHz) magnet, and into the Magnet Shop to show the astrophysicist how some of the world’s most powerful magnets are created. “He wanted to see a few of our most amazing tools and talk about the kind of research that we have going on,” Boebinger said. “It was a great opportunity to share some of our work with one of the nation’s best-known physicists.” The 55-year-old Tyson — who wanted to keep his lab visit low-key, small-scale and free of reporters — often surprised lab staff with his playful demeanor. During the tour, he stopped and knocked on the door of an office cubby usually occupied by postdoc Jackie Jarvis. She wasn’t there, but a startled graduate student was sitting in her chair. The interaction went something like this: Hi there, Tyson said, you don’t mind if we all pile in your office, do you? Too late, we were in. Can I see your chair? He pushed on the top of the empty, gray office chair, near the seat.
FLUX MAGAZINE Issue 10
“It was a great opportunity to share some of our work with one of the nation’s best known physicists.” — GREG BOEBINGER, maglab DIRECTOR
See how this chair actually gives when you sink back in it? he said. This chair was designed to conform to your body, not make your body conform to it. I had a chair like this when I was working on my doctoral thesis, and I never had any back problems from sitting in it for hours and hours because it was so well engineered. Later that day, when Tyson gave his
PowerPoint presentation — “Science as a Way of Knowing: A Cosmic Perspective” — to a packed house of nearly 1,200 people in FSU’s Ruby Diamond Concert Hall, he would talk more about good engineering vs. bad engineering. It was part of a point he wanted to drive home to his mostly student audience: The U.S. is falling behind in science, technology and engineering — but it doesn’t have to. The MagLab, of course, is living proof of how innovative and pioneering America’s scientists and engineers can be. During Tyson’s tour, Boebinger showcased some of the lab’s most cutting-edge engineering projects, including the 45 T, the Split Coil 25 T and the 900 MHz. Tyson noted how many important discoveries, such as Magnetic Resonance Imaging (MRI) machines, grew out of basic research like that under-
MagLab staff and other visitors in the lab’s atrium. From left to right: Kathleen Laufenberg (flux editor); Kristin Roberts (public affairs director); Greg Boebinger (lab director); Roxanne Hughes (educational outreach director); Neil deGrasse Tyson; Rosie Contreras (FSU student president); Harrison Prosper (FSU physics professor); and Diana DeBoer (administrator).
way at the MagLab. “In a hospital, every machine with an on/off switch that’s brought into the service of diagnosing the condition of your body without cutting you open is based on a principle of physics — and it was discovered by a physicist who had no interest in medicine at the time they made the discovery.” Although Tyson cautioned his FSU lecture audience repeatedly about the need to keep pace with the world’s best scientists and engineers (particularly those in Europe, China, Japan and Brazil), his two-hour lecture was generally laughout-loud entertaining. He included several playful references to Pluto, the planet he’s credited with demoting from official planet status. (Now deemed an icy object, Pluto is often gently referred to as a “dwarf planet.”) Tyson displayed an angry letter from a pro-Pluto third-grader upset about the demotion. It read: “Some people like Pluto. If it doesn’t exist then they don’t have a favorite planet. Please write back, but not in cursive because I can’t read in cursive.” For the third-grader, Tyson had this soft answer: “I was an accessory. I did not pull the trigger.” But for any disgruntled adults who still can’t accept Pluto’s planetary demise, he had another retort: “Get over it,” he said with good humor, “and move on!” As a reminder of the MagLab’s toptier work in engineering and science, Tyson received a package of goodies that included a Florida Bitter disk, a magnet part invented at the Tallahassee lab’s headquarters. If you missed Tyson’s Tallahassee visit, you’ll soon be able to see him as the new host for a retooled version of Carl Sagan’s “Cosmos” show. The first episode in the 13-part series is slated to air this spring on the FOX network.
FLUX MAGAZINE Issue 10 education + outreach
Lab Life 101:
Being a MagLab intern BY KATHLEEN LAUFENBERG
ach summer, the MagLab welcomes more than a dozen college interns from around the nation. They arrive eager to work in a world-class lab and full of questions: What will it be like? Will they have fun? Will they like their co-workers?
ENGAGING YOUNG SCIENTISTS
Lorena Sanchez, a 2012 REU alumna, remarks that “It’s nice to be in the lab with people who have similar interests.” Undergraduates from all over the U.S. (and sometimes the world) come to the MagLab for summer internships.
The undergraduates discover their answers as they work through their paid, eight-week internships. Depending on their interests, they may work with scientists at the MagLab’s Applied Superconductivity Center, the Magnets and Materials shop, the Ion Cyclotron Resonance program, the lab’s Geochemistry department and other research labs. Engineering student Lorena Sanchez, one of 14 interns at the lab in the summer of 2012, worked in physicist James Brooks’ lab with scientists Theo Siegrist, Eden Steven (see story page 4) and others, crafting tiny transistors using exotic materials such as gold and cocoon silk. She learned how to troubleshoot the problems that popped up during her experiments and — perhaps more importantly — learned that she en-
joyed working with other researchers. “You can laugh and talk about transistors, or get real excited about something — you’re not the only geek in the room!” she laughed. “It’s nice to be in the lab with people who have similar interests.” But be ready for a big challenge, added engineering major Daniel Escobedo. “This summer has been rewarding but hard earned,” he said during his internship. Right up to the last day, he was “struggling, trying to finish the fourth version of my poster.” The prestigious internship program, Research Experiences for Undergraduates (REU), is run by the lab’s Center for Integrating Research + Learning. Each intern receives a $3,600 stipend and, if needed, free housing.
FLUX MAGAZINE Issue 10 Students can intern at any of the MagLab’s three campuses: the main Tallahassee campus near Florida State University; the lab’s University of Florida campus in Gainesville; or at Los Alamos National Laboratory in New Mexico. No matter where an intern is placed, however, each undergrad spends two months on a project determined by the student and her mentor(s). At the end of the REU program, interns present their projects at a MagLab poster show. Sanchez’s poster, “Organic Field Effect Transistor with Silk Dielectric Layer,” showed how she used a layer of cocoon silk to build a transistor. Escobedo’s poster, “Analysis of Filament Fractures in Bronze Processed Nb3Sn Strands,” showed what happened to special high-tech wires during heat treatment and other processes.
She had another “aha!” moment, too: She discovered that she liked puzzling through the findings of her experiments, revising them and trying again. She credits Steven with inspiring her. “I would say that I didn’t have too much drive before coming here, but seeing Eden’s enthusiasm, and just being able to input my own ideas, that’s really nice. It’s more than just having a job and being told what to do and reporting the results. It’s more like … you want to be here instead of you have to be here. That’s the atmosphere of this lab.” Soon afterward, she sometimes found herself staying late at the lab “just because I want my ideas to work. It’s more like a drive now. And that’s really nice.”
Escobedo’s training included using a microscope to search for tiny fractures in superconducting wires, programming ovens used to heat-treat high-tech materials and — perhaps the most exciting — learning to use a lab torch. “Fun stuff,” he said as lab manager Bill Starch showed him how to use the torch. Escobedo had been discouraged by the lack of hands-on projects in his engineering classes. Fortunately, that changed with his internship. “Honestly, this is definitely the most satisfying experience I’ve had as far as using some of the knowledge that I’ve gained from mechanical engineering,” he said. “Because up to this point, I really haven’t been able to use any of the knowledge I’ve learned from all my classes. It’s really cool to see it in action.” But he also learned (as many of the interns do) that lab projects can take much longer than originally supposed. During the final week of his internship, he was still
Before Sanchez succeeded in making a working transistor, though, she encountered plenty of challenges. At first, none of the transistor chips she made worked properly. When power was applied to one, it took a couple of minutes to see the effect. Essentially, it was like making a light switch that, when flipped on, took a few minutes to turn the light on. And she couldn’t figure out what was causing the delay. Steven, however, reasoned that the humidity in the air might be affecting the cocoon silk in the transistor. They decided to test that theory by exposing the cocoon silk to humidity for a few hours, then see what, if anything, happened to the transistor’s response when voltage was applied. “So we did that, and we retested it — and it basically turned on almost instantly!” Sanchez said. “So that was the breakthrough: If you humidity-treat it beforehand, and make the cocoon silk no longer water soluble, you get a faster turn-on time.”
Lorena Sanchez and one of her mentors, Eden Steven, prepare to run an experiment.
working on his experiments and trying to complete his presentation poster. “It’s been awesome. I feel like I’ve gotten so much more insight into what the field is like. I really didn’t have much of a clue because I really hadn’t gotten work experience like this before. I’m definitely grateful for everything.”
RESEARCH EXPERIENCES FOR UNDERGRADS For more info about the REU program, including deadlines and application requirements, contact Jose Sanchez at email@example.com or (850) 645-0033 or go online: www.magnet.fsu.edu/education/reu
FLUX MAGAZINE Issue 10
After a series of frustrating failures, a team of MagLab scientists realized they were tackling the wrong problem.
HEAT LIQUID HELIUM 0.02° K
BY KRISTEN COYNE
t was 1997, and an ambitious, expensive and incredibly complex project — the design and construction of the National High Magnetic Field Lab’s new 45-tesla hybrid magnet — was just months from its scheduled debut. Part resistive magnet, part superconducting magnet, this new tool would be leaps and bounds stronger than any other magnet on the planet. Scientists across the world were eager to put a wide range of materials into the instrument to see what would happen to them at such high fields. Low-temperature physicists were particularly keen to combine those high magnetic fields with super cold temperatures. Such a unique experimental environment could help them learn more about the fractional quantum Hall effect, an exciting discovery that earned the 1998 Nobel Prize in physics. There was, however, a problem. A trio of scientists and engineers at the MagLab was wrestling with an ornery piece of equipment — the very tool those physicists needed to make their experiments cold.
VACUUM (4.2° K Shield)
LIQUID HELIUM 4.2° K
VACUUM (77° K Shield)
3 CM MAGNET 300° K (Room Temp.)
This bi-section of a dil fridge shows heat waves entering an experimental space through an air bubble. This tiny bubble presented a big problem for scientists because the slight heat increase would throw off experimental sample conditions and affect the results of all experiments done in the magnet.
FLUX MAGAZINE Issue 10 For more than a year, Eric Palm, Tim Murphy and Mark Jackson had tackled every puzzle the Portable Dilution Refrigerator (dubbed the “PDF” or dil fridge for short) had thrown at them. But each solution was followed by yet another problem. The men were under immense pressure: If they couldn’t make the new $250,000 contraption work, some of the cutting-edge science the hybrid magnet was designed to enable just wouldn’t happen. It was man against machine. And the machine was winning.
Helium is tricky
Dil fridges have been used with magnets for decades. They are special vessels of frigid liquid helium, with a section designed to fit inside a magnet and create an environment much colder than temperatures found in deep space. Part of the dil fridge sits atop the magnet, while a long, cylindrical “tail” extends down into the bore, or center, of the magnet. A series of vacuum-insulated layers around the dil fridge, separated by stainless steel walls, keeps the temperature in the central “mixing chamber” of the dil fridge at just a fraction of a degree above absolute zero. (See illustration.) Helium, that lighter-than-air gas that fills our party balloons, is even more useful as a liquid – at least to scientists. When it liquefies, helium dips to negative 269 degrees Celsius (negative 452 degrees Fahrenheit) – colder than the far reaches of our solar system. Because some materials behave in interesting ways when they are that cold, scientists love liquid helium. Thing is, it’s tricky to turn helium into a liquid, and tricky to keep it from reverting to a gas. Particularly if it’s in the center of a magnet. Years ago, when resistive magnets first
started reaching fields higher than 18 tesla, scientists using liquid helium noticed that something kept heating up their low-temperature experiments. They finally figured out that bubbles of helium gas were forming around those experiments, which were submerged in liquid helium. Rather than rising to the surface, the bubbles were being trapped at the center of the magnetic field, which was unfortunate because that is exactly where the experiment is located. Helium is diamagnetic – repelled by magnetic fields. And liquid helium is repelled more than helium gas because it’s more dense. So when an experiment is placed in liquid helium, in a very strong magnet, the liquid helium is repelled from the center of the magnetic field with more force than the helium gas is, leading to the creation of an unwelcome, warm helium gas bubble near the experiment. Luckily, scientists found a way around this problem by reducing the pressure above the liquid helium so it could get even colder. This produces a “superfluid,” an exotic liquid that has no resistance to flow and creates no gas bubbles.
Try, try again ... and again ... and again
However, the dil fridge built by Oxford Instruments for the MagLab’s new hybrid magnet was a unique design. It required a custom solution. The helium bubble was the last in a yearlong series of dil fridge problems that the team of Murphy, Palm and Jackson tackled. By the time they approached this final hurdle, the “D” in PDF had come to stand not for dilution, but for a four-letter word that more firmly expressed the team’s frustration. “The amazing thing was how many times we took that thing apart and put it back together,” said Palm, who then head-
MagLab staff scientists Eric Palm and Tim Murphy stand in front of the portable dilution fridge (PDF) that is a part of the 45-tesla magnet system. This important piece of equipment keeps experimental samples cold enough for researchers to study them inside the magnet. The colder the sample, the slower its molecules vibrate, and the easier it is to observe what happens in an experiment.
ed the lab’s Millikelvin Facility and is now deputy director of the MagLab. “It makes me ill just to think about it … we started hating that thing. At one point we seriously thought it was haunted.” The helium bubble stumping the team was forming in one of the insulating layers surrounding the dil fridge, transferring enough heat toward the central chamber to cause problems. Week after week, the trio brainstormed about the bubble. They considered sucking it out with a kind of straw. They considered
FLUX MAGAZINE Issue 10 By adding a heat-absorbing copper layer to the dil fridge, the scientists had effectively blocked the heat from traveling to the sample.
FindinG tHe riGHt ProbLeM LIQUID HELIUM 0.02° K
VACUUM (4.2° K Shield)
LIQUID HELIUM 4.2° K
VACUUM (77° K Shield)
3 CM MAGNET 300° K (Room Temp.)
adding a special refrigerator to the helium bath that would cool only the lower part to superfluid temperatures. They threw idea after idea at the cold, pitiless, stainless steel canister, only to have each one strike it with a dull thud and fall dead to the floor. “We were pretty worn out from problem solving,” recalled Murphy, who then worked in the Millikelvin Facility. Murphy now directs that facility and serves as interim director of the MagLab’s DC Field Facility, which houses the hybrid. “It becomes your nemesis. You solve one problem, you move forward a little, but you encounter another problem. … You just have to keep at it.” Keep at it they did. If at first you don’t succeed, and all that. Problem was, they were a bit too tenacious: They were persistently, valiantly, tirelessly trying to solve the wrong problem. Mercifully, the day came when Palm, Murphy and Jackson, an Oxford Instruments engineer assigned to debug the dil fridge, stopped thinking about the helium bubble. It was as if a camera zoomed out from the closeup they had long fixated on, revealing a wider, more telling view of the problem. Murphy recalled the magical moment. “One of us suggested, Well, why couldn’t we just short it out with copper?’ And all of us just looked at each other and said, Yeah, why couldn’t we?” You could almost see, Murphy said, the proverbial bulbs illuminate over their heads, little halos shining the light of reason on a central fact that their bubble fixation had for weeks obscured: They didn’t necessarily need to get rid of the helium bubble. They just needed to get rid of the increased heat load it placed on the central chamber. The walls between the insulating layers of the dil fridge were made of stainless steel, a material that doesn’t transport heat well. But if
they put copper between the offending helium bubble and the central chamber, that highly conductive material just might carry the heat into the liquid above the bubble and shield the dil fridge from the increased heat load. To test their idea, they bought a few sheets of very thin copper for less than $100, somewhat crudely wrapped the copper on the stainless steel tail between the liquid helium layer and the adjacent vacuum layer of the dil fridge, and secured it with yellow Mylar tape. If the test showed promise, they would remove the copper, design and build a new part properly and reinstall it. Turned out they didn’t need to. The test worked so well, they left the jerry-built copper part as is. It (and the bubble) remains there to this day, effectively transferring heat up and away from the tail of the dil fridge. “We solved the bubble problem by not solving the bubble problem,” said Murphy. “We essentially sidestepped it by looking at what was important … the real important parameter was, Can we take the heat out?’ ” For some 15 years now, the dil fridge has been performing a mind-boggling feat: Inside its central chamber — just a fraction of an inch away from room temperature — it is about as cold as it is possible to get. Stunningly, that temperature difference, achieved across so small a distance, is 500 times greater than the temperature difference between the Earth and the surface of the Sun. Looking back, Palm said, a lab culture that encourages ideas from every corner was key to solving the dil fridge problem. Some organizations may prefer a more hierarchical approach, said Palm, but that can get in the way of creative solutions. “Everybody’s throwing out stuff, whether it’s stupid or smart. Nobody takes it personally,” he said. “You bounce stuff around until you find something that works.”
FLUX MAGAZINE Issue 10
WITCHES HAT MACHINE
The HiPER 9 Tesla Magnet Stroll by physicist Steve Hill’s lab on the MagLab’s first floor, and you’re likely to stop short and stare. That’s how most folks react when they first see HiPER. HiPER is a 9-tesla magnet, and only the second one of its kind. The first is in Scotland; its Scottish builders came to the lab in 2012 to help put the MagLab’s new HiPER together. The Scots nicknamed HiPER — a scientific tool so large it would fill an average living room — their “witches hat” machine because of the 29 black, hat-sized cones that cover parts of it. You won’t find such cones on other MagLab
HiPER is actually an acronym-like scientific reference to this wild-looking machine’s ability to use High-Performance electron resonance to search for free electrons in a material. Technical adjustments are still being made to HiPER, but researchers should be able to use it in late 2014. Until then, Dr. Likai Song, who is both a medical doctor and a physicist, is experimenting with the magnet for his research. Dr. Song is part of a large, multigroup collaborative effort to create a vaccine for the Human Immunodeficiency Virus. (See Q & A on page 20.)
instruments. This unique magnet has these strange cones to absorb pulses of radiation. Essentially, the cones are the scientific equivalent of soundproof insulation in a music studio: They absorb echoes from microwaves that would otherwise skew the test data. The wild-looking HiPER is a type of Electron Paramagnetic Resonance (EPR) machine. EPR instruments detect the presence of unpaired (or free) electrons in a material. While free electrons are often short lived, they play critical roles in many processes, including photosynthesis and oxidation.
Issue 10 1800 E. Paul Dirac Drive Tallahassee, FL 32310-3706 (850) 644-0311 (850) 644-8350
on the cover A MagLab scientist dons a hardhat and headlight to explore Florida’s cave formations for clues about the earth’s paleoclimate. Check out “Darrel and the Caves,” on page 14 to read all about it.
Flux is supported by the National Science Foundation and the state of Florida
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