The Canadian Light Source

Given that the Canadian Light Source in Saskatoon produces light a million times brighter than the sun, you might well expect to be able to see it at night even from Regina. Or, upon visiting it in winter, you might think you would find thousands of sun-starved Saskatchewanians lying all around it on beach-towels in the snow, trying to soak up a few of those extra-powerful rays.

Alas, all you will see, if you visit the Light Source, as I did this week, is an impressively large open space filled with cables pipes, and more pipes, and more cables, laid out in a large circle–or two circles, really, one inside the other.

Out of sight down in the basement an electron gun injects electrons at a relatively low energy into a stainless steel tube that contains…well, nothing; it’s full (if that’s the right word) of a vacuum emptier than the space around the International Space Station. Those electrons are accelerated by microwaves down a linear accelerator into the inner “booster ring,” where they’re accelerated even more, to almost the speed of light (approximately 300,000 kilometres per second). Finally they’re sent into the outer “storage ring,” where they will circulate for hours.

Devices that spin electrons at high speed like this are called “synchrotrons.” Just as a car taking a corner too fast emits a chirp of tire-squeal and maybe a little puff of rubber smoke, electrons forced around a curve at high speed emit photons, particles of light, over a wide range of wavelengths, from infrared all the way up to hard X-rays.

(A little energy, in the form of radio-frequency waves, is constantly fed into the storage ring to replace that which is radiated away as light. As a result, at lower energy levels, electrons can keep circulating in the storage ring for up to 50 hours–by which time they have traveled a distance further than that from here to Pluto.)

As the photons leave the synchrotron, they immediately begin traveling in a straight line, so they can be drawn off in “beamlines” and then put to work by researchers needing a powerful beam of light for their studies.

Bright light, as I am beginning to appreciate more and more as I age, can help you see small objects more clearly. But you can only see extremely small structures if the light striking them has a wavelength smaller than they are. Visible light, for example, can illuminate bacteria, but to see things smaller than that, you need to move into shorter wavelengths–soft X-rays and hard X-rays.

Each beamline, then, is first sent through an “optics hutch,” where the wavelengths that aren’t required are filtered out. The beam of the desired wavelength is then passed on to an “experimental hutch,” where it illuminates the sample being studied. Data that takes only seconds to collect may then take weeks or months to analyze.

The Canadian Light Source’s brilliant light can be used to examine the ways living cells interact with drugs, to learn more about (and possibly treat) cancer, to discover better ways to clean up pollutants, to improve materials (from motor oils to plastics), and even to make nanodevices (nano- meaning “extremely small”–just a few atoms in size). Some of the most exciting work is in the field of protein analysis. Proteins, from which all life is made, have enormously complex structures, and very few have been analyzed in detail. Understanding the structure of certain key proteins may help us develop new drugs, understand diseases, improve crops and more.

The Canadian Light Source is one of only about 17 “third-generation” synchrotrons in existence anywhere. It’s barely opened, and it’s already on the verge of expansion. It has won both provincial and national engineering awards. And best of all, a large majority of the people on the teams that built and operate it are from right here in Saskatchewan.

All that, and light a million times brighter than the sun. What else can you call it but a brilliant achievement?

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