Dave Sullivan
Northern News Services

Inuvik (Apr 29/02) - While cosmic rays bombard this Delta town at double the rate many other places receive, Inuvik residents needn't break out the lead protective suits for protection.

Cosmic rays are invisible particles composed mainly of protons and helium nuclei, speeding towards Earth from the sun. Rare and more powerful ones come from far reaches of space, possibly from black holes and exploding stars.

After colliding with air in our atmosphere, cosmic rays break into cascading showers.

"The ones we detect in Inuvik have a typical energy of 10 billion electron volts," says John Bieber, a researcher with Delaware's Bartol Research Institute.

"It sounds like a big number but the total amount of energy deposited in your body is quite small. There still can be an effect. If you're at a high altitude there are health issues."

In Inuvik, each person gets hit with cosmic rays an average 100 times an hour, Bieber estimates. He says that's about twice the amount of rays reaching Southerners living at sea level.

Bieber does not believe the health of Inuvik residents is more at risk than others.

"I don't think it has serious implications. Man evolved. Cosmic rays have always been part of the natural environment."

The NWT's chief medical officer, Dr. Andre Corriveau agrees, although he admits not knowing much about cosmic rays. With all the more visible Northern health issues, they are not a priority. After thinking a moment he adds "there's not much you can do about it.

Earth's magnetic field deflects cosmic rays toward polar regions. The field, converging at the North and South poles, bulges out at the equator. Because incoming cosmic rays are charged, they tend to ride along the magnetic lines to the poles.

That's why the University of Delaware, where Bieber works, takes an interest in Inuvik.

His school looks after special equipment in Inuvik lined with 20,000 kilograms of lead. For 38 years the gear has been counting cosmic rays. Called neutron detectors, 18 were installed by the federal government.

Before being rescued from closure in 1995 by the Bartol Research Institute, the site was funded by the Inuvik Research Centre and the National Research Council of Canada.

The Bartol Institute has similar detectors in Antarctica, Labrador and six other places.

The latest one, costing $1.2 million US opened in October 2000 at Aurora College in Fort Smith.

Collected information will be used to predict solar flares, which cause, among other things, power blackouts and satellite damage.

The flares travel slower than the accompanying cosmic rays. Bieber says equipment is being developed to take advantage of the rays' near-light speed, providing a few hours notice.

Airlines are very interested. Fear is mounting that high up, cosmic radiation can harm pilots and even frequent fliers, Bieber and others say. That's where concern lies about the rays causing mutations and cancer, especially in male reproductive organs.

A European cosmic ray study focusing on pilots should finish collecting data next year.

According to the online magazine Physics Web, the European Union recently labelled cosmic rays an occupational hazard for high-altitude pilots.

Bieber says they're exposed to a hundred times the normal amount of cosmic ray radiation.

Two Canadian radiation scientists at University of Sherbrooke propose that cosmic rays contribute to ozone depletion by interacting with man-made chlorofluorocarbons.

Their conclusions are controversial, according to New Scientist.