Mag Lab MacGyvers

User support scientists use creativity to save the day

By Susan Ray

When you think of scientists at work, do you conjure up images of lab coats? Clean rooms? Microscopes, beakers, test tubes and Bunsen burners?

Well, if that's the case, you better clear your brain's cache, because here at the Mag Lab, inside our magnet "cells" and beyond, science is messy, often unpredictable and very creative. Yes, creative.

This is the realm of experimental physicists. Their job is to make observations and gather data about different physical phenomena, whereas theoretical physicists focus on predicting or explaining physical phenomena.

In experimental physics, getting the data is job 1, and it's why scientists travel hundreds and even thousands of miles to the Mag Lab for just one week of magnet time. Magnet time is like the day before a final exam in terms of pressure. Scientists come in early and stay late, subsisting on a steady diet of convenience foods and caffeine. Much is at stake (beyond the travel expense): Graduate students who accompany the scientists may need the data to complete their Ph.D. thesis. Publications, the lifeblood of basic research, hang in the balance. So when things go wrong or threaten to interfere with an experiment, as they often do, Mag Lab MacGyvers (user support scientists) stand at the ready.

For the uninitiated, "MacGyver" was a staple of mid-1980s prime-time television. The title character used practical application of scientific know-how and clever use of common household items – in particular a Swiss Army knife – to beat the bad guys.

While Mag Lab MacGyvers aren't dealing with life and death, they are dealing with stressed and often jet-lagged scientists, who have traveled many miles for magnet time. So when the going gets rough, they spring into action armed with only their wits – and tape.

Tape: A science staple

A layer of graphite one atom thick holds great promise for the future of microelectronics. It's called graphene – but how exactly does a person slice one atom's thickness off what is essentially a pencil trace?

Paul Cadden-Zimansky, a Columbia University-Magnet Lab postdoctoral fellow who studies graphene, said scientists tried several different methods to get very thin pieces of graphite. A group at Cornell University put pieces of graphite in a liquid solution, then subjected the liquid to sonic vibrations to break up the graphite into thinner sheets.

Cadden-Zimansky's boss at Columbia, Philip Kim, tried to attach graphite to a microscopic cantilever; the cantilever functioned as a sort of "nanopencil" that could be tapped on a surface, leaving pieces of thin graphite.

But as it turns out, the best method for capturing graphene is … cellophane tape (you may know it better by its brand name, Scotch tape).

A group of scientists at Manchester University in England placed a speck of graphite on a piece of tape, then folded it over and pulled it apart – and folded it over and pulled it apart, over and over again. With each folding and unfolding, the graphite became thinner and thinner, until eventually some of those specks were one atom thick. Voilà! We have graphene.

"Since the development of the tape method people have fabricated larger area graphene by using other methods," said Cadden-Zimansky. "However, for getting the highest quality graphene, the cellophane-tape method is still what's employed."

In a pinch, 3-D glasses will do

One day, a user was working in SCM3 (that's the name of a magnet, but for these purposes, you can think of it as a secret underground military installation). He was doing optics experiments on semiconductor nanocrystals that were going so well, he decided he wanted to take additional measurements. Doing so would require a thin-film circular polarizer, and that moment, there wasn't enough time to order it from a distributor. Data was on the line!

That's when Mag Lab physicist Steve McGill started thinking about 3-D movies.

Huh?

You see, McGill had recently seen a 3-D film and worn the Real-D glasses.

"In the past, I have not been a fan of 3-D films because experiencing the 3-D effect for long periods of time usually gave me a headache," said McGill. "However, I was pleasantly surprised to discover that I did not suffer these side effects with the newer technology that's being used in films today."

So like any self-professed science nerd would, he brought a pair of the Real-D glasses home to play with.

"I discovered that the lenses in these glasses are actually circular polarizers," said McGill. "Anyone can easily verify this by putting them on, closing one eye, and then looking at his/her reflection in a mirror. Since right and left circular polarization are exchanged upon reflection, the wearer will notice that the lens over the open eye looks dark in the mirror, while the lens over the closed eye appears clear."

As the user anxiously awaited word about his experiment's fate, McGill raced home (OK, he drove home) to retrieve the glasses.

Safely back at SCM3, McGill and the visiting scientist performed delicate surgery on the lenses (they cut one out), placed it in the probe, and the measurement was successful. No additional magnet time was required!

Let there be light

The 900 MHz superconducting magnet is one of a kind. With a magnetic field strength of 21.1 tesla, it pushes the limits of current magnet technology. You may have never heard of a thing such as a superconducting magnet, but if you've ever had an MRI scan, you've been in one. The 900 is like a supersized version of a hospital MRI, which is only about 2 tesla.

"Tesla" is the scientific unit of measure of magnetic field strength; to put the 900's power in perspective, the Earth's magnetic field is one twenty thousandth of a tesla. And while 21.1 tesla is plenty strong, what makes the 900 special is the size of its bore, the place in the middle of the magnet where the experiments go. At about 4 inches in diameter, the 900's bore is about as wide as an orange. Other magnets of comparable field have typical bore sizes of 2 inches. Because of its large bore size, the 900 can be used to study small living animals. So you could (and we do) call the 900 the strongest MRI scanner in the world.

Imagine the possibilities! An MRI scanner with that much resolution could be used to study all kinds of neurological and other diseases in animal models. But you can only do research if you can see what you're doing. And lighting the 900 pit – which is a "bottom loading" magnet, hence the pit – is not as easy as it sounds.

How in the world do you light a magnet whose very properties cause lights not to work properly? Clues and possible treatments for Parkinson's, Lou Gehrig's disease, muscular dystrophy and more are just waiting to be discovered! There has to be a way to light the pit so that scientists can see well when putting probes into the magnet.

"In the stray field of the magnet, most light bulbs don't work," said Bill Brey, a scholar scientist and probe engineer in the lab's Nuclear Magnetic Resonance user program. "The filaments in incandescent bulbs will shake due the field and quickly break; the electrons in fluorescent tubes will veer off into the wall of the tube – so the tubes don't light."

Brey's team thought they had the answer with the new low energy light emitting diode (LED) bulbs. But as it turned out, the LED bulbs worked for a few months, then quit.

"There are magnetic parts in the voltage converters that allow the bulbs to run off the 110 V lab wiring," said Brey. No matter how tiny they may be, magnetic parts in a magnetic field present problems. So Brey turned to low-voltage LED landscape lights.

"They have aluminum or plastic housings to avoid rust, so we can use them in our stray field zone," said Brey. "And they don't have the voltage converters of the old lights."

And just like that, Mag Lab MacGyvers helped push the frontiers of science while saving researchers unnecessary eyestrain. "We are not above using everyday products in our research," said Brey. Even in his grad school days, Brey tinkered. "My wife saw me making a radio frequency shield for an animal MRI coil out of a file folder and aluminum foil, and of course Scotch tape, back in grad school," said Brey. "That shield worked well, too."

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