GAMMA RAYS

Evening Post, Volume CXIII, Issue 29, 4 February 1932, Page 3

GAMMA RAYS

SEEKING THEIR ORIGIN

A NEW THEORY

(From "The Post's" Representative^ ' '■''.;);'- LONDON, 3rtl December,-:: ■ : ; Lord Rutherford and his -helpers;hayt'-'.. been making what he called a cbncea-' trated attach on the origin of the Gam- . ma.Rays,. and.a.new..theory has bW elucidated. Lord; Rutherford was.open- ' ing. the annual congress of the-BrltisH ! Institute of Radiology when he-made this announcement. • The discovery of the-X-Tays by R<mt. gen in 1895, he said, marked a veritable epoch inthe^hisWryofsc^ only because- of the,disc O very' itself but because ■if brought in its 'train two other great discoveries—that of radioactivity by Becque'rel in i 896, . which opened up a new science/and had had an enormous -influence on the development of our ideas'on' the structure of matter, and "the -discovery of 'the' eleci trpn in the' following year; by Sir" 'J J. Thomson. ; The discovery of X-ra'yi was, a dividing • line between" what might, be called the older and the newer physics. It provided us with a weapon, of great flexibility and power for throwing light' on: the internal structure 'of matter,- and its utility was asyet by no means exhausted. ; ■' •■ ■ ■ ' - • • . Lord Eutherf ord proceeded to. speak of the difficult-problem of the origin of the gamma- rays; from radium and the other radib:-a«th*e- bodies. •■ For a , lon<r time it had been known' that the gamma rays were a very penetrative type/of X-rays, but the question of: how they were produced was very difficulftoans■wer. -It was at first natural to suppose that, as the gamma rays appeared -to come from bodies,, that produced -4tae '" swift beta rays or electrons; they wove connected with:a sudden' escape of th,e electrons, expelled from a; nucleus; "Tv recent years,, however, .opinion had -hardened that the gamma rays inuEt be duo to the.motions of heavier particles/like the protons or alpha particles,'-making up the nucleus. In the last year—and. hq might say, in.the last fewVweeks-^----there had been a concentrated attack: oa this question in the speaker's laboratory ■at ■■ Cambridge;' and '.he -was, liow sure .that the gammarays arose. from; jthe alphas rays, and had. nothing whatever to do -with the .electrons' from" the nucleus. ■ ■ ■ ' ~"■"■"■"•.' :-■ ■: ■■: The idea they now envisaged vraa this'niinute'nucleus probably coilsisted:'mainly .of aiptia particles—that ■was, of helium nuclei. Th ere was every ' reason to believe .that vnormally these alpha particles were all in the* same quantum - state,. but that wienya; beta particle was shot' out from1' the..'atom itihad'a remarkable power of disturbing. 'the alpha, particles^ While: some of the alpha particles ; mightbe shoV'up to/a higher, level of energy,and might rest there for an .. infinitesimal time, they felt back, and'in falling* back gaite out their energy in the form of a gainma'ray." It.looked to/Him as-if virtually 'all the -gamma rays' 'which they, observed—at any rate, all those of higher frequency-^were derived fromvthe motions of aiptia particles in the nucleus. '. The recognition of : this, h« thought, would;throw lighloh the structure of I: ,-, -:/.:-:\{.3wyAiOTiX)P; JraorpNS^; ■■, l ":-l;''.': •^Sir James: Jeans, in an.address :to*the institute, .endeavoured; to: answer . tEe.. question; ''What is 'Eadiatibn? *' ••'•.;.; ■) ;.■ : .He said: *'Eadiation is made-of bullets ..of: .electrical energy, hurtling through empty Space.' .They are spiit-; nihg round as if fired, from,a rifle, but are also, capable of : wav«;iike motionSj'',-„. . 'These bullet^like ■■p'^ticles1 '■ Sir: janiesi' termed f'phptons.^''"-.: ";■:;; 'l:v; ."When we' pay ' our ./electric;liglit bills,''he said,"we are in;effect buy*' * ing. photons. The electric 'light; company may tell us we are' paying 6d a unit for our energy. What they really mean is that we are paying £17,000,000 an.ounce for our photons'. • '■'Yet, the sun is distributing photon j' free of charge throughout space at the rate of over 4,000,000 tons 'a second. This gives us some idea of the amazing prodigality and generosity of Nature as compared -with similar qualities in the electric light companies!" '(Laughter.) ; v "If we could learn the secret of annihilating matter," Sir James added, "we could turn an ounce of base matter of * any kind into an ounce of photons, and we should have energy of which the present value is about £17,000,000. "Doubtless prices would be lower then!"