Book Title: Microcosmology Atom in Jain Philosophy and Modern Science
Author(s): Jethalal S Zaveri, Mahendramuni
Publisher: Jain Vishva Bharati
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Atom in Modern Science
55
As we have already seen, the discovery of radio-activity proved the complexity of nuclear structure beyond any doubt and paved the way for artificial nuclear transformations. Earlier, bombardment of the nuclei by artificially accelerated charged particles such as alpha, protons, etc. was the method employed for nuclear transformations. But the electric charges carried by such particles caused them to lose much of its kinetic energy while passing through the atomic bodies and prevented them from coming sufficiently close to nuclei of the bombarded material. Thc bullcis to be used for more efficient bombardment are neutrons which, because, they do not have an electric charge, can penctrate the heavily fortified electrical wall surrounding the positively charged nuclei. Just as coal fire needs oxygen to keep it going, a nuclear fire needs the neutrons to maintain it. but uncharged projectiles viz., neutrons are not easily available in free form as they are tightly locked up within the nuclei of atoms recaptured as soon as they are kicked out. There is only one way to sustain the nuclear reaction and that is to create a self-multiplication process i.c. each bombarding neutron must liberate more than one other neutron which in their turn would act as bullets.
Late in 1938, Rahn and Strass man discovered that atomic energy can be released through the fission process of uranium nuclei. Like the two pieces of a broken spring, the two halves of a broken heavy nucleus begin their existence in a state of violent vibrations. Before coming to rest, each of the fragments emits a neutron.
It must be remembered that, although the neutrons are much more effective nuclear projectiles than the charged particles, their effectiveness in producing the fission is, however, not cent percent. The important condition for a sustained nuclear transformation is progressive neutron-production or a chainreaction for which it is necessary that a hundred neutrons entering the substance must release many more than a hundred neutrons.
There are two types of chain reactions : controlled and uncontrolled. The controlled rcaction is analogous to the burning of petrol in automobile engine. The atom-splitting bullets - the neutrons - are first slowed down from speeds of more than ten
