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New Accelerator Makes Food Safer, Combats Acid Rain

March 17, 1985|United Press International

LIVERMORE, Calif. — On the bottom of a blue-tiled pool sits a compact, silver machine that physicists say has such wide-ranging applications as making food safer to eat and harder to spoil and eliminating acid rain.

The new electrical device is the culmination of 27 years of research at the Lawrence Livermore National Laboratory, and it's called the magnetically switched induction linear accelerator.

This latest technological wonder--a miniature cousin of a long line of linear accelerators, some of which stretch for miles--serves as a radiation source that, unlike any in practical use today, can be turned on and off.

Ready in 2 Years

Its creators say it should be ready for commercial use within two years.

"It can be readily reproduced and for under $1 million," Richard Briggs, deputy associate director for beam research at the lab, said in an interview.

Designed by a team led by Daniel Birx, the 2-million electron-volt machine is being tested in a series of food-preservation experiments.

Scientists from the lab, which has pioneered the development of linear induction accelerators since 1958, and the University of California, Davis, are studying insect deinfestation and effects of electron beams on flavor and texture.

The Beauty of It

"The beauty of this little fellow, 6 feet long and some 4 feet across, is that when it's turned on, it emits an intense electron beam, and when it's turned off, it's perfectly safe, unlike a traditional radiation source that presents a constant danger of radioactivity," Steven Matthews, senior physicist at Livermore, said in an interview.

"One of its many practical applications--food processing and preservation--may reduce the need for carcinogenic fumigants used on produce in this country and curtail the 20% to 30% of food destruction due to spoilage every year in Third World countries."

Some 30 countries use ionizing radiation to eliminate certain bacteria and sterilize certain components within food, Matthews said.

Although no irradiated food is consumed in America, this country uses its radiation-processing facilities to do the job for others.

Solving Problems

"Europe, which lacks adequate facilities, sends us its fresh fish to be irradiated, and more and more countries want the same process. With huge amounts of food to be processed, I believe we will need dangerously high levels of the radioactive isotope, the current radiation source," Matthews said.

"The isotope is constantly radioactive and has to be kept enclosed in a lead container. Transporting it by air or truck can have deadly consequences. The accelerator can solve these problems."

The researchers also will look at fumigating produce with electron beams instead of chemicals, some of which have been shown to leave cancerous residues in food.

Some foods may not be tolerant of radiation, Matthews said, and "we're looking at this."

The machine also could help eliminate acid rain, he said.

Acid Rain Threat

Some environmentalists say growing industrial emissions of sulfur dioxide from smokestacks, along with oxides of nitrogen from motor vehicles and industrial smokestacks, are a major threat to forests, lakes and rivers.

Acid deposition forms when oxides of sulfur or nitrogen mix with atmospheric water to make sulfuric or nitric acid.

In California, there have been reports of precipitation falling in Los Angeles and San Jose with roughly 10 times the acidity of normal rain. Rain as acidic as vinegar was reported in Pasadena and San Bernardino, while fog almost as caustic as stomach acid was recorded in Corona el Mar in 1982.

"Gases are hard to remove from smokestacks. But if you shine an electron beam at the gases, the electron rearranges the molecule of gas and changes it, say, from sulfur dioxide to ammonium sulfate--a particulate that can be removed much easier than gas and, in addition, be used as fertilizer," Matthews said.

Could Fit Smokestack

"The machine sitting in our lab can do the job right now. It can easily be redesigned to fit into a smokestack."

In the lab, the water-tight accelerator is kept immersed in water to shield workers from radiation produced when the machine is in use.

The main cylinder is surrounded by four small canisters attached to black cables that carry the electrical power from generator equipment sitting in 6-foot-tall racks above the pool.

"In experiments, we load a canister with food, lower it into the pool with a small crane, pass it in front of the cylinder, turn the machine on, irradiate the food for a few moments, rotate the canister to get all sides of the food, then bring it up," Briggs said. "It's absolutely safe and non-radioactive."

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