ΜΑΒΟΗ, 1948. Chalk River Radioactive Isotopes Qpen New Horizons In Scientific Research Tae work being done inside the National Research Council’s 20,000, ooo dollar atomic energy plant at Chalk River, Ontario, Canada, is “opening vast new vistas in the realms of physi- cal, chemical and biological research. The door to the Atomic Future has been opened. What lies ahead no one cin know. With research going for- ward in many. directions from the suientific crossroads at Chalk. River, atomic energy is hammering its way i1to more and more spheres of human activity. Scientists themselves can- not tell what the outcome will be— they cannot say at this. stage what ultimate effect new discoveries will have on the life of mankind, but many a scientific and industrial revolution is bound to take place. Scientists have had to devise a whole new technique for the handling of radio- active materials of which, because of the dangers involved, only infinitesi- mal quantities can be used. The controlled, slow-motion atomic explo- sion which occurs in the “ pile” is shielded by hundreds of tons of lead and concrete, but the amounts of radioactive materials produced in most cases are minute. Instruments used vary enormously in size and complexity from huge hoists to the delicate micro-balance. The latter, invented and built by the men of Chalk River, and_so delicate in its action that it can weigh accurately as little as one ten-millionth of a gram, depends on the torsion (twisting) of pure thread spun finer than the silk of a spider’s web. Two years of experimentation with a low-energy pile have been followed, after exhaustive tests, by the successful operation of a big heavy-water pile which now produces radioactive iso- topes of incalculable yesearch value. An isotope is simply one form of an element. In order to obtain radioactive iso- topes, a definite element or one of its compounds is chosen as a “ target” to be irradiated. When the target. is subjected to bombardment by neu- trons generated in the pile, radio- isotopes of some other element are formed. In this way, phosphorus isotopes are produced from sulphur. The samples thus obtained, which cannot be converted to military use, are kept in lead-protected bins avail- able to qualified workers in various fields, not only in Canada, but also abroad. Isotopes are especially useful in the 55 fields of tracer chemistry and tracer biology. An example of the former is found in agricultural research now in progress at Saskatoon, Saskatche- wan, Canada, with the object of determining what proportions of pho- sphorus plants obtain from the soil, and from fertilizer supplied by man. An isotope (radio-phosphorus) is mixed with the fertilizer. As the (Photo by Chris Lund) Workers of the Chalk River plant relax in the staff lounge at Deep River, eleven miles away by road. Recreational activities range from skiing, boating, archery and square kniting to art, chess and music apprectation. plant takes its nourishment from the ground, it gives off radiations in proportion to the amount of phospho- rus assimilated from the fertilizer. These radiations are measured by a Geiger counter. This is only one of the countless uses to which isotopes can be put in the unrelenting process of pushing back the frontiers of scientific knowledge. ene EEE EEE SLES SS AAO DSS OATS SONS OCS ORONO AES AEE ON