A couple of years ago I wrote a column about one of the biggest scientific projects of our time, the Superconducting Super Collider, currently under construction in Texas. I didn’t know at the time that a Regina man is one of the scientists working on it.
Dr. Torre Wenaus is a staff physicist at the Lawrence Livermore National Laboratory in Livermore, Calif., just outside San Francisco. He (along with many others, of course) is working on one of the most crucial elements of the SSC, one of its two large detectors, the devices that scientists hope will give them a new understanding into both how the universe works and how it began.
I was showing Dr. Wenaus around the Saskatchewan Science Centre last week (it seemed only appropriate that a scientists from the SSC should be touring the SSC) and I took the opportunity to talk to him about his project.
The Superconducting Super Collider, Dr. Wenaus said, is the next step in a course of inquiry that’s one of the oldest there is: What is the nature of matter?
This century, that inquiry has been pursued with a series of particle accelerators, each more powerful than the last, each designed to smash subatomic particles together or into a target to create new particles that can only exist at higher energies. Along the way, each new device has spawned not only a better understanding of the nature of matter, but new technologies. One early particle accelerator, for example, was the cathode ray tube, or electron accelerator. You probably have one of these particle accelerators in your living room, currently presenting you with an infomercial for hair restorative.
Particle accelerators have also moved from the realm of the physicist to that of the physician: they provide the precise beams of radiation needed to treat cancer.
The latest generation of particle accelerators are huge, ring-shaped colliders, so called because they accelerate two beams of particles in opposite directions, then run them head-on into each other. And calling these colliders huge is far more than a figure of speech: the Large Electron-Positron Collider outside Geneva where Dr. Wenaus has also conducted research is 27 kilometres in circumference, and the Superconducting Super Collider dwarfs that, at 87 kilometres in circumference.
It’s the size that enables these huge colliders to obtain the incredible energies needed to find new particles. Basically, the Superconducting Super Collider is two vacuum tubes surrounded by magnets (superconducting magnets, chilled by liquid helium, in this case, because of the enormously strong magnetic fields required). Two beams of protons (in the case of the SSC) are injected into these tubes and begin to go around and around the ring in opposite directions, the magnets serving to curve the beams around the ring’s bends. Periodically, the beams pass through accelerators that make them travel just a little bit faster, until they approach the speed of light. Travelling that fast, the beams release radiation as they go around curves, scrubbing off energy just as a car scrubs off speed as it screeches its tires around a corner. The huge size of the SSC flattens out the curve as much as possible, minimizing that loss of energy.
Eventually, the two beams of protons (although they’re not continuous beams, but more like pulses, each pulse a few centimetres long and about the width of a human hair) are brought together. The two beams are travelling at exactly the same speed, so when a proton from one hits a proton from another, both protons come to a dead stop and all the energy stored up in them from their trips around the ring is released as “a whole menagerie of particles,” in Dr. WenausÕs words. At which point the detector he’s working on comes into play, and (he hopes) picks up evidence of particles nobody has seen before.
One of the particles the SSC is designed to detect (if it exists) is something called the Higgs boson, a particle suggested in response to one of the big unanswered questions of physics, “Why does matter have mass?” In general, the basic attributes of matter arise from various subatomic particles. The basic particle of light, for instance, is the photon; the basic particle of electricity is the electron; atomic nuclei are held together by particles called “gluons” (who says physicists don’t have a sense of humor?), and so on. The best theories as to why matter has mass predicts the existence of a particle called the Higgs boson, but it doesn’t predict at what energy level that particle will be found—and so far, no-one has found it.
But scientists have good reason to believe that the Higgs boson has to be in the energy range between 800 million electron volts and one trillion electron volts, and it’s that region that the Superconducting Super Collider will allow scientists to probe effectively for the first time.
Like its predecessors among particle accelerators, the SSC will have enormous technological spin-offs, Dr. Wenaus said. It has already resulted in improvements in superconducting technology that could have implications in the fields of power transmission and communications. And like other accelerators, it may spawn whole new technologies. Whether the Higgs boson turns up or not, he said, he’s certain that “whatever it is that shows up will rewrite all the textbooks. It’s impossible to say what technologies that will provide.”
But while all the spin-offs are great, they’re not what motivates Dr. Wenaus or the other scientists on the project. “The motivation,” he said, “is the continuing pursuit of the nature of matter.”