STUDY OF COSMIC RAYS

Press, Volume LXXXVI, Issue 26128, 2 June 1950, Page 10

STUDY OF COSMIC RAYS

EXPERIMENTS NEAR NORTH POLE

CANADIAN AND BRITISH SCIENTISTS

(From CHARLES B. LYNCH, a Reuter Correspondent)

Canadian and British scientists, conducting experiments in the region of the northern magnetic pole, and in aircraft flying high above the Atlantic, are breaking new ground in the study of cosmic rays. These experiments are believed to parallel similar ones going on in Russia. The study of cosmic rays forms part of one of the most exciting and one of the most difficult to understand sections of the vast field of nuclear physics. The scientists themselves do not know what cosmic rays are, but they feel that solution of the mystery may open the door to undreamed-of stores of energy. The experiments are under the auspices of the National Research Council of Canada, and are directed from Ottawa Laboratories, so filled with |iuge bits of mysterious equipment that they look like the setting for a horror movie. The walls are covered with multi-coloured charts dealing with isotopes, atoms, electrons, mesons, protons and photons. Scientists produce micro-photo-graphs that look like ink-spattered blotters and long rolls of paper that look like records for a player piano, and they tell you that each minute, hundreds of cosmic particles are hurtling through your body—six particles a square inch a minute. They are travelling at 186,000 miles a second, and after passing through the body they continue thousands of feet into the earth. They aren’t just waves, but particles of matter —and they have been detected in the deepest mines in the world.

This enormqus velocity, in what to scientists is quite a heavy particle, is the “come on” that has lea scientists in many nations to study the mysterious visitors that come whizzing in out of space. Not even the hugest cyclotron imaginable to-day can set projectiles moving at the speed of the cosmic particles and scientists believe .that these bits of matter may be invaluable in future years in the field of atomic fission. The cosmic particles can pass through 18 feet of lead. No means has yet been found of measuring their energy—scientists merely place it at “several thousand millions of volts.” The new experiments fall into two classes. The first, under Dr. D. C. Rose, involves counting cosmic particles by using Geiger counters, which record the bombardment from outer space. The counters are set up in groups of feur, shielded by 18| inches of lead to weed out less virile electrons and rays that are flying about in the atmosphere. . . One of these installations, weighing more than a ton and a half, was taken to the Arctic last summer by Dr. Rose, and set up at the joint United States-Canadian weather station at Resolute Bay, Cornwallis Island. The station is 200 miles north-east of the. magnetic pole. The equipment was carried on ships of a United States Navy Task Force carrying supplies to the Arctic weather stations. After Dr. Rose had it in working order, it was left in the charge of the weather station staff, who send Dr. Rose the recording rolls by airmail. Jagged lines on the paner show some particles passing through the equipment at a rate of 16 a minute, and others going through at a rate of more than 200 a minute. First Continuous Recording Dr Rose’s experiments represent the first'attempt at continuous recording of cosmic rays in the Far North, and should provide valuable data on now cosmic intensity is affected by changes in barometric pressure. electrical storms, seasons of the year and sunspots. A similar installation is in operation in Ottawa, to determine the difference in intensity of cosmic rays at 85 degrees latitude, where <he magnetic pole exerts a strong pull, and at 45 degrees latitude, at Ottawa. The other project is being conducted by Dr. E. Pickup, a native of Rochdale, England, who came to Canada (three years ago after working as a 1 “back room boy,” on radar at the Telecommunications Research Establishment, ' Dr. Pickup is now on the staff of the National Research Council of Canada. Where Dr. Rose uses Geiger coun-

ters to measure cosmic particles, Dr. Pickup uses photographic plates. This method was originated in the physics department of Bristol University. Bristol. England, and has since been taken up by the Bartol Research Foundation, at Swarthmore. Pennsylvania. Dr. Pickup went to Churchill. Manitoba, last winter to test special photographic plates, which were sent into Che stratosphere attached to balloons. The experiments were not too successful, however, as recovering the balloons turned out to be more of a job for an Arctic explorei- than a nuclear scientist. Further work will be done at Churchill this winter. More successful have been Dr.

Pickup’s experiments aboard com--1 mercial aircraft flying the Atlantic. , These experiments were started on airI craft of British Overseas Airways, and are being continued on pressurised, high-altitude aircraft of Trans-Canada Air Lines. 1 Each T.C.A. aircraft carried a seal- ; ed parcel containing a number of Dr. 1 Pickup’s specially-emulsified plates, which are under the care of the navi- ! gator. After 200 air hours, the plates ! are brought to Ottawa, developed and I studied through , a microscope. Dr. Pickup has hundreds of enlargements I showing what happens when a cosmic particle strikes and disintegrates ’ a particle of sliver in the emulsion. I They look like children’s cut-outs. 1 and Dr. Pickup is filled with youthi ful enthusiasm as he explains what ' they mean. “It’s not fission. It’s actual, complete disintegration. That’s I because the cosmic particles travel so 1 fast.” He-calls these events “peculiar occurrences," and the photographs that result he calls “cosmic stars.” Pointing to one series of dots on a photograph. he said: “That one pleased us very much. Nobody had ever seen lhat type of electron before.” Then he explained how he knew it was an electron. The cosmic particles that bombard the earth are not actually visitors from outer space. They are really a sec-ond-hand commodity. What "happens i is that the primary cosmic rays crack 1 into tile outer reaches of the earth’s I atmosphere, about 100,000 feet up. ; There, they hit other particles that 'are floating about in that section of I the atmosphere. It is these secondary i particles, suddenly propelled at the speed of light, that hurtle into the earth. They actually are particles—infinitesimal bits of iron or carbon. Scientists call them mesons—and in size thev come between the atom and the electron. They are charged particles, which explains that they make a bee-line for the north (and south) magnetic poles. To get a line on the primary particles. which hold the secret of the origin of the cosmic rays, scientists have to get above the 100.000-foot level. The lead in this work has so far been taken by the United States, using post-war versions of the German V-2 rockets, equipped with cosmic ray detectors.